Network node, method, and non-transitory computer-readable storage medium for receiving data from external network node

Abstract

This network node may comprise: a first port connected to a first external network node; a second port connected to a second external network node; a memory storing instructions; and at least one processor comprising processing circuitry. The instructions, when individually or collectively executed by the at least one processor, may cause the network node to: determine whether a connection state of the first port is a normal state or an abnormal state, on the basis of at least one of a first state message acquired from the first external network node and a second state message acquired from the second external network node; receive downlink traffic from the first external network node according to the determination that the connection state of the first port is the normal state; and receive the downlink traffic from the second external network node according to the determination that the connection state of the first port is the abnormal state.

Description

Network node for receiving data from an external network node, method, and non-transient computer-readable storage medium

[0001] The present disclosure relates to a network node for receiving data from an external network node, a method, and a non-transient computer-readable storage medium.

[0002] As transmission capacity increases in wireless communication systems, function splitting, which functionally separates base stations, is being applied. Due to function splitting, base stations can be separated into a distributed unit (DU) and a radio unit (RU).

[0003] The information described above may be provided as related art for the purpose of aiding understanding of the present disclosure. No claim or determination is made as to whether any of the foregoing may be applied as prior art related to the present disclosure.

[0004] A network node is provided. The network node may include a first port connected to a first external network node. The network node may include a second port connected to a second external network node and configured to transmit traffic received from the first external network through the first port to the second external network node. The network node may include a memory comprising one or more storage media for storing instructions. The network node may include at least one processor comprising processing circuitry. The instructions may cause the network node to determine whether the connection status of the first port is normal or abnormal based on at least one of a first status message obtained from the first external network node or a second status message obtained from the second external network node, when executed individually or collectively by the at least one processor. When the above instructions are executed individually or collectively by the at least one processor, they may cause the network node to receive downlink traffic containing address information of the network node from the first external network node through the first port, depending on the determination that the connection state of the first port is the normal state. When the above instructions are executed individually or collectively by the at least one processor, they may cause the network node to receive downlink traffic from the second external network node through the second port, depending on the determination that the connection state of the first port is the abnormal state.

[0005] A method is provided. The method may be performed at a network node having a first port connected to a first external network node and a second port connected to a second external network node, configured to transmit traffic received from the first external network through the first port to the second external network node. The method may include an operation of determining whether the connection state of the first port is normal or abnormal based on at least one of a first status message obtained from the first external network node or a second status message obtained from the second external network node. The method may include an operation of receiving downlink traffic containing address information of the network node from the first external network node through the first port, based on the determination that the connection state of the first port is normal. The method may include an operation of receiving downlink traffic from the second external network node through the second port, based on the determination that the connection state of the first port is abnormal.

[0006] A non-transient computer-readable storage medium is provided. The non-transient computer-readable storage medium may store one or more programs. The one or more programs may include instructions that cause the network node to determine whether the connection state of the first port is normal or abnormal based on at least one of a first status message obtained from the first external network node or a second status message obtained from the second external network node, when executed by the network node having a second port connected to a first external network node and a second port configured to transmit traffic received from the first external network through the first port to the second external network node. The one or more programs may include instructions that cause the network node to receive downlink traffic containing address information of the network node from the first external network node through the first port, depending on the determination that the connection state of the first port is normal when executed by the network node. The above one or more programs may include instructions that cause the network node to receive the downlink traffic from the second external network node through the second port, upon determining that the connection state of the first port is abnormal when executed by the network node.

[0007] Figure 1 illustrates an example of a wireless communication system.

[0008] Figure 2 illustrates an example of an interface between an upper network node and a lower network node.

[0009] Figure 3 illustrates an example of the functional configuration of a network node.

[0010] Figure 4 illustrates an example of network nodes connected in series.

[0011] FIGS. 5a and 5b illustrate examples of network nodes with redundant connections implemented.

[0012] FIGS. 6a through 6f illustrate examples of the operations of network nodes following a communication failure in a link.

[0013] FIG. 7a illustrates examples of operations in which a network node receives downlink traffic.

[0014] FIG. 7b illustrates examples of operations in which a network node transmits uplink traffic.

[0015] Throughout the drawings, the same reference numerals will be understood to refer to the same parts, components, and structures.

[0016] The terms used in this disclosure are used merely to describe specific embodiments and are not intended to limit the scope of other embodiments. A singular expression may include a plural expression unless the context clearly indicates otherwise. Terms used herein, including technical or scientific terms, may have the same meaning as generally understood by those skilled in the art described in this disclosure. Terms used in this disclosure that are defined in a general dictionary may be interpreted as having the same or similar meaning as they have in the context of the relevant technology, and are not to be interpreted in an ideal or overly formal sense unless explicitly defined in this disclosure. In some cases, even terms defined in this disclosure are not to be interpreted to exclude the embodiments of this disclosure.

[0017] In the various embodiments of the present disclosure described below, a hardware-based approach is described as an example. However, since the various embodiments of the present disclosure include techniques using both hardware and software, the various embodiments of the present disclosure do not exclude a software-based approach.

[0018] Terms used in the following description to refer to data (e.g., data, traffic, uplink traffic, downlink traffic, status message, response message), terms to refer to values, terms for operation states (e.g., operation, process), terms to refer to objects, terms to refer to network entities (e.g., router, switch, server, network node, upper network node, lower network node, base station, DU (distributed unit), RU (radio unit)), terms to refer to device components, etc., are examples provided for the convenience of explanation. Accordingly, the present disclosure is not limited to the terms described below, and other terms having equivalent technical meanings may be used. Additionally, terms such as '...part', '...device', '...object', '...body' used below may refer to at least one shape structure or a unit that processes a function.

[0019] Additionally, in this disclosure, expressions of "greater than" or "less than" may be used to determine whether a specific condition is satisfied or fulfilled; however, this is merely for the purpose of expressing an example and does not exclude descriptions of "greater than" or "less than." Conditions described as "greater than" may be replaced with "greater than," conditions described as "less than" may be replaced with "less than," and conditions described as "greater than and less than" may be replaced with "greater than and less than." Furthermore, "A" to "B" below refer to at least one of elements from A (including A) to B (including B). Below, "C" and / or "D" refers to including at least one of "C" or "D," i.e., {"C", "D", "C" and "D"}.

[0020] This disclosure describes various embodiments using terms used in some communication standards (e.g., 3GPP (3rd Generation Partnership Project), ETSI (European Telecommunications Standards Institute), xRAN (extensible radio access network), O-RAN (open-radio access network), but these are merely illustrative examples. Various embodiments of this disclosure can be easily modified and applied to other communication systems.

[0021] Figure 1 illustrates an example of a wireless communication system.

[0022] Referring to FIG. 1, FIG. 1 illustrates a base station (110) and a terminal (120) as part of nodes using a wireless channel in a wireless communication system. FIG. 1 illustrates only one base station, but the wireless communication system may include other base stations identical or similar to the base station (110).

[0023] A base station (110) is a network infrastructure that provides wireless access to a terminal (120). The base station (110) has coverage defined based on the distance over which it can transmit signals. In addition to being a base station, the base station (110) may be referred to as an 'access point (AP)', 'eNodeB (eNB)', '5G node (5th generation node)', 'next generation nodeB (gNB)', 'wireless point', 'transmission / reception point (TRP)', or other terms having an equivalent technical meaning.

[0024] A terminal (120) is a device used by a user and communicates with a base station (110) via a wireless channel. The link from the base station (110) to the terminal (120) is referred to as a downlink (DL), and the link from the terminal (120) to the base station (110) is referred to as an uplink (UL). Additionally, although not shown in FIG. 1, the terminal (120) and another terminal can communicate with each other via a wireless channel. In this case, the link between the terminal (120) and another terminal (device-to-device link, D2D) is referred to as a sidelink, and the sidelink may be used interchangeably with the PC5 interface. In some other embodiments, the terminal (120) may be operated without user involvement. According to one embodiment, the terminal (120) is a device that performs machine type communication (MTC) and may not be carried by the user. Additionally, according to one embodiment, the terminal (120) may be a narrowband (NB)-Internet of Things (IoT) device.

[0025] The terminal (120) may be referred to as 'user equipment (UE)', 'customer premises equipment (CPE)', 'mobile station', 'subscriber station', 'remote terminal', 'wireless terminal', 'electronic device', or 'user device' or other terms having an equivalent technical meaning.

[0026] The base station (110) can perform beamforming with the terminal (120). The base station (110) and the terminal (120) can transmit and receive wireless signals in a relatively low frequency band (e.g., FR 1 (frequency range 1) of NR). Additionally, the base station (110) and the terminal (120) can transmit and receive wireless signals in a relatively high frequency band (e.g., FR 2 (or FR 2-1, FR 2-2, FR 2-3), FR 3) of NR) and a millimeter wave (mmWave) band (e.g., 28 GHz, 30 GHz, 38 GHz, 60 GHz)). To improve channel gain, the base station (110) and the terminal (120) can perform beamforming. Here, beamforming may include transmit beamforming and receive beamforming. The base station (110) and the terminal (120) can impart directivity to the transmitted signal or the received signal. To this end, the base station (110) and the terminal (120) can select serving beams through a beam search or beam management procedure. After the serving beams are selected, subsequent communication can be performed through a resource that is in a quasi-co-located (QCL) relationship with the resource that transmitted the serving beams.

[0027] If large-scale characteristics of the channel that transmitted the symbol on the first antenna port can be inferred from the channel that transmitted the symbol on the second antenna port, the first antenna port and the second antenna port can be evaluated as being in a QCL relationship. For example, the large-scale characteristics may include at least one of a delay spread, a Doppler spread, a Doppler shift, an average gain, an average delay, and a spatial receiver parameter.

[0028] In FIG. 1, it is described that both the base station (110) and the terminal (120) perform beamforming, but the embodiments of the present disclosure are not necessarily limited thereto. In some embodiments, the terminal may or may not perform beamforming. Also, the base station may or may not perform beamforming. That is, either the base station or the terminal may perform beamforming, or neither the base station nor the terminal may perform beamforming.

[0029] In the present disclosure, a beam refers to a spatial flow of a signal in a wireless channel, formed by one or more antennas (or antenna elements), and this formation process may be referred to as beamforming. Beamforming may include at least one of analog beamforming or digital beamforming (e.g., precoding). A reference signal transmitted based on beamforming may include, for example, a demodulation-reference signal (DM-RS), a channel state information-reference signal (CSI-RS), a synchronization signal / physical broadcast channel (SS / PBCH), or a sounding reference signal (SRS). Additionally, an IE such as a CSI-RS resource or an SRS-resource may be used as a configuration for each reference signal, and such a configuration may include information associated with the beam. Information associated with a beam may refer to whether the configuration (e.g., CSI-RS resource) uses the same spatial domain filter as other configurations (e.g., other CSI-RS resources within the same CSI-RS resource set) or a different spatial domain filter, or which reference signal it is QCLed with, and if so, what type (e.g., QCL type A, B, C, D).

[0030] Conventionally, in communication systems with a relatively large cell radius of base stations, each base station was installed to include the functions of a digital processing unit (or DU (distributed unit)) and an RF (radio frequency) processing unit (RF processing unit, or RU (radio unit)). However, as high frequency bands are used in 4G (4th generation) and / or subsequent communication systems (e.g., 5G) and the cell coverage of base stations decreases, the number of base stations required to cover a specific area has increased. Consequently, the burden of installation costs for operators to install base stations has also increased. To minimize base station installation costs, a structure has been proposed in which the DU and RU of a base station are separated, with one or more RUs connected to a single DU via a wired network, and one or more geographically distributed RUs deployed to cover a specific area. Below, with reference to FIG. 2, deployment structures and extension examples of base stations according to various embodiments of the present disclosure are described.

[0031] Figure 2 illustrates an example of an interface between an upper network node and a lower network node.

[0032] FIG. 2 illustrates an interface between an upper network node and a lower network node. The interface between the upper network node and the lower network node may include a fronthaul interface. Fronthaul refers to the space between entities between a wireless LAN and a base station, unlike backhaul between a base station and a core network. FIG. 2 illustrates an example of a fronthaul structure between an upper network node (210) and one lower network node (220), but this is merely for convenience of explanation and the present disclosure is not limited thereto. In other words, an embodiment of the present disclosure may also be applied to a fronthaul structure between one upper network node and a plurality of lower network nodes. For example, an embodiment of the present disclosure may be applied to a fronthaul structure between one upper network node and two lower network nodes. Additionally, an embodiment of the present disclosure may also be applied to a fronthaul structure between one upper network node and three lower network nodes.

[0033] For example, an upper network node may include a DU (digital unit / distributed unit). An upper network node may be referred to as a DU. A lower network node may include a RU (radio unit) or an MMU (massive MIMO unit). A lower network node may be referred to as a RU or an MMU.

[0034] Referring to FIG. 2, the base station (110) may include an upper network node (210) and a lower network node (220). The fronthole (215) between the upper network node (210) and the lower network node (220) may be operated via an Fx interface. For the operation of the fronthole (215), an interface such as eCPRI (enhanced common public radio interface) or ROE (radio over ethernet) may be used.

[0035] As communication technology develops, mobile data traffic increases, and consequently, the bandwidth requirements for the fronthaul between the digital unit and the wireless unit have increased significantly. In a deployment such as a C-RAN (centralized / cloud radio access network), the upper network node (210) performs functions for PDCP (packet data convergence protocol), RLC (radio link control), MAC (media access control), and PHY (physical), and the lower network node (220) can be implemented to perform functions for the PHY layer in addition to RF (radio frequency) functions.

[0036] The upper network node (210) may be responsible for upper layer functions of the wireless network. For example, the upper network node (210) may perform functions of the MAC layer and parts of the PHY layer. Here, parts of the PHY layer are functions of the PHY layer that are performed at a higher level, and may include, for example, channel encoding (or channel decoding), scrambling (or descrambling), modulation (or demodulation), and layer mapping (or layer demapping). According to one embodiment, if the upper network node (210) conforms to the O-RAN standard, it may be referred to as an O-DU (O-RAN DU) (or DU). The upper network node (210) may be replaced and represented as a first network entity or DU for a base station (e.g., gNB) in the embodiments of the present disclosure as necessary.

[0037] The lower network node (220) can perform lower layer functions of the wireless network. For example, the lower network node (220) can perform RF functions, which are part of the PHY layer. Here, part of the PHY layer refers to functions of the PHY layer that are performed at a relatively lower level than the upper network node (210), and may include, for example, iFFT transformation (or FFT transformation), CP (cyclic prefix) insertion (CP removal), and digital beamforming. The lower network node (220) may be referred to as an 'access unit (AU)', 'access point (AP)', 'transmission / reception point (TRP)', 'remote radio head (RRH)', 'radio unit (RU)', or other terms having an equivalent technical meaning. According to one embodiment, if the sub-network node (220) conforms to the O-RAN standard, it may be referred to as an O-RU (O-RAN RU) (or RU). The sub-network node (220) may be replaced with a second network entity or RU for a base station (e.g., gNB) in the embodiments of the present disclosure as needed.

[0038] In the above example, it is described that the upper network node (210) includes a DU and the lower network node (220) includes an RU, but the embodiments of the present disclosure are not limited thereto. A base station according to the embodiments may be implemented in a distributed deployment according to a centralized unit (CU) configured to perform the functions of the upper layers of the access network (e.g., packet data convergence protocol (PDCP), radio resource control (RRC)) and a distributed unit (DU) configured to perform the functions of the lower layers. In this case, the distributed unit (DU) may include a digital unit (DU) and a radio unit (RU). Between a core network (e.g., 5G core or next generation core (NGC)) and a radio network (RAN), the base station may be implemented in a structure in which the CU, DU, and RU are arranged in that order. The interface between the CU and the distributed unit (DU) may be referred to as the F1 interface.

[0039] For example, a centralized unit (CU) can be connected to one or more DUs and perform functions at a higher layer than the DUs. For instance, the CU can perform functions at the radio resource control (RRC) and packet data convergence protocol (PDCP) layers, while the DU and RU can perform functions at lower layers. The DU can perform radio link control (RLC), media access control (MAC), and some functions of the physical (PHY) layer (high PHY), while the RU can perform the remaining functions of the PHY layer (low PHY). Additionally, as an example, a digital unit (DU) can be included in a distributed unit (DU) depending on the distributed deployment implementation of the base station. The following description describes the operations of DU and RU unless otherwise defined, but various embodiments of the present disclosure may be applied to both base station deployments including CU and deployments where DU is directly connected to the core network (i.e., implemented by integrating CU and DU into a single entity base station (e.g., NG-RAN node)).

[0040] Figure 3 illustrates an example of the functional configuration of a network node.

[0041] The configuration of the network node (301) exemplified in FIG. 3 can be understood as a configuration of a base station (110), a terminal (120), an upper network node (210), a lower network node (220), a server, a switch, a router, a gateway, a modem, a firewall, an access point, or a network element performing an equivalent function. However, the present disclosure is not limited thereto. Terms such as '...part', '...unit' used below refer to a unit that processes at least one function or operation, and this may be implemented in hardware or software, or a combination of hardware and software.

[0042] Referring to FIG. 3, the network node (301) may include a processor (300), memory (310), a first port (321), a second port (322), and / or a transceiver (330). However, the present disclosure is not limited thereto. For example, the network node (301) may not include at least some of the components shown in FIG. 3, or may further include components not shown in FIG. 3. For example, the network node (301) may further include one or more ports.

[0043] The processor (300) controls the overall operations of the network node (301). The processor (300) may be referred to as a control unit. The processor (300) may include control circuits and / or processing circuits. For example, the processor (300) transmits and receives signals through the transceiver (330) (or through the backhaul communication unit). Additionally, the processor (300) writes and reads data to and from memory (310). Furthermore, the processor (300) may perform the functions of a protocol stack required by the communication standard. Although only the processor (300) is shown in FIG. 3, according to other implementation examples, the network node (301) may include two or more processors.

[0044] For example, the processor (300) may include various processing circuits and / or multiple processors. For example, the term “processor” as used herein, including in the claims, may include various processing circuits including at least one processor, and one or more of said at least one processor may be configured to perform the various functions described below in a distributed manner, individually and / or collectively. As used below, where “processor,” “at least one processor,” and “one or more processors” are described as being configured to perform various functions, these terms encompass situations where one processor performs some of the cited functions and another processor(s) perform other parts of the cited functions, and / or situations where one processor can perform all of the cited functions. Additionally, said at least one processor may include a combination of processors that perform the enumerated / disclosed various functions, for example, in a distributed manner. At least one processor may execute program instructions to achieve or perform the various functions.

[0045] Memory (310) can store data such as basic programs, applications, and configuration information for the operation of the network node (301). Memory (310) may be referred to as a storage unit. Memory (310) can store instructions for the operations of the network node (301). Memory (310) may include hardware components for storing data and / or instructions that are input to or / or output from the processor (300). A set of one or more instructions may be referred to as a program, firmware, operating system, process, routine, sub-routine, and / or application. For example, instructions may represent operations and / or actions to be performed on the data by the processor (300) of the network node (301). And, memory (310) provides the stored data upon the request of the processor (300). Memory (310) may be composed of volatile memory, non-volatile memory, or a combination of volatile memory and non-volatile memory.

[0046] The first port (321) may be referred to as an interface for transmitting network traffic or receiving network traffic. For example, the first port (321) may be implemented as a physical interface or a logical interface. The first port (321) may be used to transmit data to an external network node (e.g., RU, DU, CU, switch, router, server) connected to the first port (321) or to receive data from an external network node connected to the first port (321).

[0047] The second port (322) may be referred to as an interface for transmitting network traffic or receiving network traffic. For example, the second port (322) may be implemented as a physical interface or a logical interface. The second port (322) may be used to transmit data to an external network node (e.g., RU, DU, CU, switch, router, server) connected to the second port (322) or to receive data from an external network node connected to the second port (322).

[0048] According to one embodiment, a network node (301) may be connected in series with a plurality of external network nodes. For example, the network node (301) may be connected to a first external network node through a first port (321) and to a second external network node through a second port (322). For example, the first network node may be included in or correspond to a higher layer than the network node (301). For example, the network node (301) may correspond to a DU and the first network node may correspond to a CU. For example, the second network node may be included in or correspond to a lower layer and / or the same layer as the network node (301). For example, the network node (301) may correspond to a DU and the second network node may correspond to a DU and / or RU. The network node (301) may obtain data (e.g., downlink traffic) from the first external network node through the first port (321). A network node (301) can transmit, provide, or send data obtained from a first external network node to a second external network node through a second port (322). For example, the first port (321) may be referred to as a primary port and / or a P port, and the second port (322) may be referred to as a reserved port and / or an R port.

[0049] The transceiver (330) can perform functions for transmitting and receiving signals in a wired communication environment. The transceiver (330) may include a wired interface for controlling a direct connection between devices through a transmission medium (e.g., copper wire, optical fiber). For example, the transceiver (330) may transmit an electrical signal to another device through a copper wire or perform conversion between an electrical signal and an optical signal. According to one embodiment, a network node (301) may communicate with a radio unit (RU) through the transceiver (330). In this respect, the transceiver (330) may be referred to as a fronthall transceiver. As an example, but not limited to, the network node (301) may be connected to a core network or a distributed CU through the transceiver (330).

[0050] The transceiver (330) may perform functions for transmitting and receiving signals in a wireless communication environment. For example, the transceiver (330) may perform a conversion function between a baseband signal and a bit sequence according to the physical layer specifications of the system. For example, when transmitting data, the transceiver (330) generates complex symbols by encoding and modulating the transmitted bit sequence. Also, when receiving data, the transceiver (330) restores the received bit sequence by demodulating and decoding the baseband signal. Additionally, the transceiver (330) may include a plurality of transmission and reception paths. Also, according to one embodiment, the transceiver (330) may be connected to a core network or to other nodes (e.g., an integrated access backhaul).

[0051] The transceiver (330) can transmit and receive signals. The transceiver (330) can function as a fronthole transceiver. For example, a network node (301) can transmit or receive management plane (M-plane) messages through the transceiver (330). For example, the network node (301) can transmit or receive synchronization plane (S-plane) messages through the transceiver (330). For example, the network node (301) can transmit or receive control plane (C-plane) messages through the transceiver (330). For example, the network node (301) can transmit or receive user plane (U-plane) messages through the transceiver (330). Although only a transceiver (330) is shown in FIG. 3, according to other implementation examples, the network node (301) may include two or more transceivers.

[0052] The transceiver (330) transmits and receives signals as described above. Accordingly, all or part of the transceiver (330) may be referred to as a 'communication unit', 'transmitter unit', 'receiver unit', or 'transmitter / receiver unit'. Furthermore, in the following description, transmission and reception performed via a wireless channel are used to mean that processing as described above is performed by the transceiver (330).

[0053] Although not illustrated in FIG. 3, the transceiver (330) may further include a backhaul transceiver for connecting to a core network or another base station. The backhaul transceiver provides an interface for communicating with other nodes within the network. That is, the backhaul transceiver converts a sequence of bits transmitted from a base station to another node, e.g., another access node, another base station, an upper node, a core network, etc., into a physical signal, and converts a physical signal received from another node into a sequence of bits.

[0054] The configuration of the network node (301) illustrated in FIG. 3 is merely an example, and the examples of network nodes (301) that perform embodiments of the present disclosure are not limited to the configuration illustrated in FIG. 3. In some embodiments, some configurations may be added, deleted, or changed.

[0055] In the present disclosure, techniques for a network node to receive traffic (or data) transmitted from a core network or to transmit traffic to a core network may be described. A network node may be connected to a plurality of external network nodes. According to embodiments of the present disclosure, a network node may determine or identify the connection status of a network node. For example, a network node may determine or identify the connection status of a port of a network node. Depending on the connection status of a network node, a network node may change the method for receiving or transmitting traffic. Such methods will be described and illustrated with reference to FIGS. 4 through 7b.

[0056] FIG. 4 illustrates an example of network nodes connected in series. A structure in which network nodes are connected in series may be referred to as a daisy-chain connection structure. A structure in which network nodes are connected in series may be referred to as, or correspond to, a structure in which each network node is configured to receive traffic (or data) from a previous network node and transmit traffic to the next node.

[0057] Referring to FIG. 4, the connection state of each of the network nodes (401, 402, 403) may be a normal state. For example, the connection state of each of the network nodes (401, 402, 403) being a normal state may include the connection state of each of the first ports (e.g., first port (411), first port (421), first port (431)) of the network nodes (401, 402, 403) being a normal state. In the present disclosure, a normal state may be referred to as, or correspond to, a connection state in which a network node (e.g., network node (301)) can receive downlink traffic transmitted from the core network through the first port among the first port (e.g., first port (321)) and the second port (e.g., second port (322)). Additionally, the normal state may be referenced as, or correspond to, a connection state in which a network node can transmit uplink traffic to the core network through the first port among the first port and the second port. For example, in FIG. 4, the connection state of the network node (401) may be a normal state because the network node (401) communicates with the network node (404) using the link (440) connected to the first port (411). For example, in FIG. 4, the connection state of the network node (402) (or the connection state of the first port (421)) may be a normal state because the network node (402) communicates with the network node (404) using the link (441) connected to the first port (421). For example, the link (441) may be connected to the link (440) through the network node (401).

[0058] In the present disclosure, an abnormal state may be referred to as, or correspond to, a connection state in which a network node (e.g., network node (301)) cannot receive downlink traffic transmitted from a core network through a first port (e.g., first port (321)) and a second port (e.g., second port (322)). Additionally, an abnormal state may be referred to as, or correspond to, a connection state in which a network node cannot transmit uplink traffic to a core network through a first port among a first port and a second port. In the present disclosure, the statement that the connection state of the network node (301) is an abnormal state may include the connection state of the first port (321) being an abnormal state. A network node (301) in an abnormal connection state will be illustrated and described in FIG. 5B.

[0059] A network node (301) may use a status message to identify or determine the connection status of a network. For example, the status message may be obtained from another network node (e.g., network node (301)) connected to the network node (301). For example, the status message may be obtained through the first port (321) of the network node (301) and / or the second port (322) of the network node (301). For example, each network node may obtain the status message of another network node connected to the network node through the port of the network node. In other words, the network node (301) may transmit or provide the status message of the network node (301) to another network node. For example, the status message of the network node (301) may indicate the connection status of the network node (301). For example, the status message may include the connection status of the first port (321) of the network node (301). For example, a status message may include information indicating the status of the second port (322) of the network node (301). For example, the network node (301) may transmit or provide the status message to another network node connected to the second port (322) only through the second port (322) among the first port (321) and the second port (322). The network node (301) may refrain from outputting the status message of the network node (301) through the first port (321). By refraining from outputting the status message of the network node (301) through the first port (321), the network node (301) may prevent a looping problem. For example, a looping problem may be referred to as causing performance degradation of the network by infinitely repeating the transmission of data (e.g., status message) along a circular path in the network.

[0060] Network nodes (401), network nodes (402), and / or network nodes (403) may be connected in series. The network nodes (401, 402, 403) illustrated in FIG. 4 are merely one embodiment and the present disclosure is not limited thereto. Network nodes not illustrated in FIG. 4 may be further connected after network node (403).

[0061] A network node (401) may be an example of a network node (301) of FIG. 3. A first port (411) of a network node (401) may be an example of a first port (321) of FIG. 3. A second port (412) of a network node (401) may be an example of a second port (322) of FIG. 3. A network node (401) may be connected to a network node (404) through a first port (411). For example, a first port (411) may be connected to a port of a network node (404). For example, a first port (411) and a network node (404) may be connected via a link (440). A network node (401) and a network node (404) may be physically or logically connected via a link (440) and may transmit or receive traffic (or data). For example, the link (440) may include a fronthaul and / or a backhaul. For example, the link (440) may be referred to as an external link and / or a hot link.

[0062] A network node (401) may be connected to a network node (402) through a second port (412). For example, the second port (412) may be connected to a first port (421) of the network node (402). For example, the second port (412) and the first port (421) of the network node (402) may be connected via a link (441). The network node (401) and the network node (402) may be physically or logically connected via the link (441) and may transmit or receive traffic (or data). For example, the link (441) may be referred to as a chained link.

[0063] According to one embodiment, a network node (401) can identify or determine that the connection status of the network node (401) (or the first port (411)) is normal. The network node (401) can receive or obtain downlink traffic from the network node (404) through the first port (411). For example, downlink traffic may be transmitted to the network node (401) through the link (440). For example, the network node (401) can receive downlink traffic for each of the network nodes (401, 402, 403). For example, downlink traffic for each of the network nodes (401, 402, 403) may include address information for each of the network nodes (401, 402, 403). The address information may represent or correspond to a unique identifier used to identify the network node on the network or to transmit data (e.g., uplink traffic, downlink traffic). For example, address information may include a MAC (media access control) address and / or an IP (internet protocol) address. For example, address information may be represented as the source address of data or the destination address of data. For example, for downlink traffic for each of the network nodes (401, 402, 403), the destination address of the downlink traffic may represent the address information of each of the network nodes (401, 402, 403). For example, for uplink traffic for each of the network nodes (401, 402, 403), the source address of the uplink traffic may represent the address information of each of the network nodes (401, 402, 403).

[0064] The network node (401) can identify or determine that the connection status of the network node (401) (or the first port (411)) is normal. The network node (401) can deliver, provide, or transmit downlink traffic for the network node (402) and downlink traffic for the network node (403) to the network node (402) through the second port (412). For example, the network node (401) can deliver, provide, or transmit downlink traffic for the network node (402) and / or downlink traffic for the network node (403) to the network node (402) through the second port (412) in response to receiving or acquiring downlink traffic for the network node (402) and / or downlink traffic for the network node (403). For example, downlink traffic for network node (402) and / or downlink traffic for network node (403) can be delivered to or transmitted to network node (402) through link (441).

[0065] According to one embodiment, the network node (401) can identify or determine that the connection status of the network node (401) (or the first port (411)) is normal. The network node (401) can transmit or provide uplink traffic to the network node (404) through the first port (411). For example, the uplink traffic can be transmitted to the network node (404) through the link (440). For example, the network node (401) can transmit uplink traffic for the network node (401) to the network node (404) through the first port (411). For example, the uplink traffic for the network node (401) may include address information of the network node (401).

[0066] The network node (401) can identify or determine that the connection status of the network node (401) (or the first port (411)) is normal. The network node (401) can receive uplink traffic for the network node (402) and / or uplink traffic for the network node (403) from the network node (402) through the second port (412). For example, the uplink traffic for the network node (402) may include address information of the network node (402). For example, the uplink traffic for the network node (403) may include address information of the network node (403). The network node (401) can deliver, provide, or transmit the uplink traffic for the network node (402) and the uplink traffic for the network node (403) to the network node (404) through the first port (411). For example, in response to receiving or acquiring uplink traffic for network node (402) and / or uplink traffic for network node (403) from network node (402), network node (401) may deliver, provide, or transmit uplink traffic for network node (402) and / or uplink traffic for network node (403) to network node (404) through the first port (411). For example, uplink traffic for network node (402) and / or uplink traffic for network node (403) may be delivered or transmitted to network node (404) through the link (440).

[0067] According to one embodiment, the network node (401) may transmit or provide a status message of the network node (401) to the network node (402) through the second port (412). For example, the status message of the network node (401) may indicate that the connection status of the network node (401) (or the first port (411)) is normal.

[0068] A network node (402) may be an example of a network node (301) of FIG. 3. A first port (421) of a network node (402) may be an example of a first port (321) of FIG. 3. A second port (422) of a network node (402) may be an example of a second port (322) of FIG. 3. A network node (402) may be connected to a network node (401) through a first port (421). For example, a first port (421) may be connected to a second port (412) of a network node (401). For example, a first port (421) and a second port (412) of a network node (401) may be connected via a link (441). A network node (402) may be connected to a network node (403) through a second port (422). For example, the second port (422) may be connected to the first port (431) of the network node (403). For example, the second port (422) and the first port (431) of the network node (403) may be connected via a link (442). The network node (402) and the network node (403) may be physically or logically connected via the link (442) and may transmit or receive traffic (or data). For example, the link (442) may be referred to as a chained link.

[0069] According to one embodiment, the network node (402) can identify or determine that the connection status of the network node (402) (or the first port (421)) is normal. The network node (402) can receive or obtain downlink traffic from the network node (401) through the first port (421). For example, the network node (402) can identify that the connection status of the network node (402) (or the first port (421)) is normal in response to receiving downlink traffic from the network node (404) through the first port (421) (or link (441)). For example, downlink traffic can be transmitted to the network node (402) through the link (441). For example, the network node (402) may receive or obtain downlink traffic for the network node (402) and downlink traffic for the network node (403) from the network node (401) through the first port (421). For example, the downlink traffic for the network node (402) may include address information of the network node (402). The downlink traffic for the network node (403) may include address information of the network node (403).

[0070] According to one embodiment, the network node (402) can identify or determine that the connection status of the network node (402) (or the first port (421)) is normal. The network node (402) can deliver, provide, or transmit downlink traffic for the network node (403) to the network node (403) through the second port (422). For example, the network node (402) can deliver, provide, or transmit downlink traffic for the network node (403) to the network node (403) through the second port (422) in response to receiving or acquiring downlink traffic for the network node (403). For example, downlink traffic for the network node (403) can be delivered or transmitted to the network node (403) through the link (442).

[0071] According to one embodiment, the network node (402) can identify or determine that the connection status of the network node (402) (or the first port (421)) is normal. The network node (402) can transmit or provide uplink traffic to the network node (401) through the first port (421). For example, the uplink traffic can be transmitted to the network node (401) through the link (441). For example, the network node (402) can transmit uplink traffic for the network node (402) to the network node (401) through the first port (421). For example, the uplink traffic for the network node (402) may include address information of the network node (402).

[0072] The network node (402) can identify or determine that the connection status of the network node (402) (or the first port (421)) is normal. The network node (402) can receive uplink traffic for the network node (403) from the network node (403) through the second port (422). For example, the uplink traffic for the network node (403) may include address information of the network node (403). The network node (402) can deliver, provide, or transmit uplink traffic for the network node (403) to the network node (401) through the first port (421). For example, the network node (402) can deliver, provide, or transmit uplink traffic for the network node (403) to the network node (401) through the first port (421) in response to receiving or obtaining uplink traffic for the network node (403) from the network node (403). For example, uplink traffic for network node (403) can be delivered or transmitted to network node (401) through link (441).

[0073] According to one embodiment, the network node (402) may transmit or provide a status message of the network node (402) to the network node (403) through the second port (422). For example, the status message of the network node (402) may indicate that the connection status of the network node (402) (or the first port (421)) is normal.

[0074] A network node (403) may be an example of a network node (301) of FIG. 3. A first port (431) of a network node (403) may be an example of a first port (321) of FIG. 3. A second port (432) of a network node (403) may be an example of a second port (322) of FIG. 3. A network node (403) may be connected to a network node (402) through a first port (431). For example, a first port (431) may be connected to a second port (422) of a network node (402). For example, a first port (431) and a second port (422) of a network node (402) may be connected via a link (442). Although not shown in FIG. 4, the network node (403) can be connected to another network node (e.g., network node (301)) through the second port (432). For example, the second port (432) can be connected to the first port (e.g., first port (321)) of another network node.

[0075] According to one embodiment, the network node (403) can identify or determine that the connection status of the network node (403) (or the first port (431)) is normal. The network node (403) can receive or obtain downlink traffic for the network node (403) from the network node (402) through the first port (431). For example, downlink traffic for the network node (403) can be transmitted to the network node (403) through the link (442). For example, downlink traffic for the network node (403) may include address information of the network node (403).

[0076] According to one embodiment, the network node (403) can identify or determine that the connection status of the network node (403) (or the first port (431)) is normal. The network node (403) can transmit or provide uplink traffic to the network node (402) through the first port (431). For example, the uplink traffic may be transmitted to the network node (402) through the link (442). For example, the network node (403) can transmit uplink traffic for the network node (403) to the network node (402) through the first port (431). For example, the uplink traffic for the network node (403) may include address information of the network node (403).

[0077] According to one embodiment, the network node (403) can output a status message of the network node (403) through the second port (432). For example, the status message of the network node (403) may indicate that the connection status of the network node (403) (or the first port (431)) is normal.

[0078] A network node (404) may be an example of a network node (301) of FIG. 3. For example, a network node (404) may be configured to transmit or forward downlink traffic (or data) transmitted from a core network to a network node corresponding to address information included in the downlink traffic. For example, a network node (404) may be included in a higher layer than network nodes (401, 402, 403). For example, network nodes (401, 402, 403) may correspond to a DU (or RU), and a network node (404) may correspond to a CU. As another example, a network node (404) may be connected to a CU. For example, a network node (404) may be used to transmit or forward downlink traffic transmitted from a CU to a network node corresponding to address information included in the traffic. For example, the network node (404) can identify a transmission path for transmitting to a network node according to address information included in the downlink traffic. For example, the network node (404) can transmit downlink traffic for the network node (402) to the network node (401) because the network node (402) is connected in series to the network node (401).

[0079] According to one embodiment, the length of the links (440, 441, 442) used in the serial connection structure illustrated in FIG. 4 may be shorter than the length of the links (440, 531, 541) used in the redundant connection structure of FIG. 5a and 5b to be described later. The cost for the serial connection structure illustrated in FIG. 4 may be less than the cost for the redundant connection structure of FIG. 5a and 5b to be described later.

[0080] FIGS. 5a and 5b illustrate examples of network nodes with redundant connections implemented. Each of network node (401) and network node (402) may have redundant connections implemented. Network node (401) may be connected to network node (404) through a first port (411). Network node (401) may communicate with network node (404) through the first port (411). If network node (401) cannot communicate with network node (404) through the first port (411), it may communicate with network node (404) through a second port (412). Network node (402) may be connected to network node (404) through a first port (421). Network node (402) may communicate with network node (404) through the first port (421). If the network node (402) cannot communicate with the network node (404) through the first port (421), it can communicate with the network node (404) through the second port (422). A method of the network node (401) communicating with the network node (404) through the second port (412) and / or a method of the network node (402) communicating with the network node (404) through the second port (422) will be described with reference to FIGS. 5a and 5b.

[0081] Referring to FIG. 5a, the network node (401) may be an example of the network node (301) of FIG. 3. The first port (411) of the network node (401) may be an example of the first port (321) of FIG. 3. The second port (412) of the network node (401) may be an example of the second port (322) of FIG. 3. The network node (401) may be connected to the network node (404) through the first port (411). For example, the first port (411) may be connected to a port of the network node (404). For example, the first port (411) and the network node (404) may be connected via a link (440). The network node (401) may be connected to the network node (402) through the second port (412). For example, the second port (412) may be connected to the second port (422) of the network node (402). For example, the second port (412) and the second port (422) of the network node (402) may be connected via a link (541). The network node (401) and the network node (402) may be physically or logically connected via the link (541) and may transmit or receive traffic (or data). For example, the link (541) may be referred to as a standby link.

[0082] According to one embodiment, the network node (401) can identify or determine that the connection status of the network node (401) (or the first port (411)) is normal. The network node (401) can receive or obtain downlink traffic from the network node (404) through the first port (411). For example, downlink traffic can be transmitted to the network node (401) through the link (440). For example, the network node (401) can receive downlink traffic for the network node (401). For example, downlink traffic for the network node (401) may include address information of the network node (401).

[0083] According to one embodiment, the network node (401) can identify or determine that the connection status of the network node (401) (or the first port (411)) is normal. The network node (401) can transmit or provide uplink traffic to the network node (404) through the first port (411). For example, the uplink traffic can be transmitted to the network node (404) through the link (440). For example, the network node (401) can transmit uplink traffic for the network node (401) to the network node (404) through the first port (411).

[0084] According to one embodiment, the network node (401) may transmit or provide a status message of the network node (401) to the network node (402) through the second port (412). For example, the status message of the network node (401) may indicate that the connection status of the network node (401) (or the first port (411)) is normal.

[0085] A network node (402) may be an example of a network node (301) of FIG. 3. A first port (421) of a network node (402) may be an example of a first port (321) of FIG. 3. A second port (422) of a network node (402) may be an example of a second port (322) of FIG. 3. A network node (402) may be connected to a network node (404) through a first port (421). For example, the first port (421) may be connected to a port of a network node (404). For example, the first port (421) and the network node (404) may be connected via a link (531). For example, the link (531) may include a fronthaul and / or backhaul. For example, the link (531) may be referred to as an external link and / or a hot link.

[0086] A network node (402) can be connected to a network node (401) through a second port (422). For example, the second port (422) can be connected to a second port (412) of a network node (401). For example, the second port (422) and the second port (412) of a network node (401) can be connected via a link (541). The network node (401) and the network node (402) are physically or logically connected via the link (541) and can transmit or receive traffic (or data).

[0087] According to one embodiment, the network node (402) can identify or determine that the connection status of the network node (402) (or the first port (421)) is normal. The network node (402) can receive or obtain downlink traffic from the network node (404) through the first port (421). For example, downlink traffic can be transmitted to the network node (402) through the link (531). For example, the network node (402) can receive downlink traffic for the network node (402). For example, downlink traffic for the network node (402) may include address information of the network node (402).

[0088] According to one embodiment, the network node (402) can identify or determine that the connection status of the network node (402) (or the first port (421)) is normal. The network node (402) can transmit or provide uplink traffic to the network node (404) through the first port (421). For example, the uplink traffic can be transmitted to the network node (404) through the link (531). For example, the network node (402) can transmit uplink traffic for the network node (402) to the network node (404) through the first port (421).

[0089] The network node (402) may transmit or provide a status message of the network node (402) to the network node (401) through the second port (422). For example, the status message of the network node (402) may indicate that the connection status of the network node (402) (or the first port (411)) is normal.

[0090] A network node (404) may be an example of a network node (301) of FIG. 3. For example, the network node (404) may be configured to transmit or forward downlink traffic (or data) transmitted from a core network to a network node corresponding to address information included in the downlink traffic. For example, the network node (404) may be included in a higher layer than the network nodes (401, 402). For example, the network nodes (401, 402) may correspond to a DU (or RU), and the network node (404) may correspond to a CU. As another example, the network node (404) may be connected to a CU. For example, the network node (404) may be used to transmit or forward downlink traffic transmitted from a CU to a network node corresponding to address information included in the downlink traffic. For example, the network node (404) may identify a transmission path for transmitting to a network node corresponding to address information included in the downlink traffic. For example, the network node (404) may decide to send downlink traffic for the network node (401) to the network node (401) via the link (440). For example, the network node (404) may decide to send downlink traffic for the network node (402) to the network node (402) via the link (531).

[0091] Referring to FIG. 5b, the connection status of the network node (401) may be abnormal. For example, a communication failure (550) may occur in the link (440). For example, the cause of the communication failure (550) may include various causes such as physical damage to the link (440), failure of a port of the network node (404) connected to the link (440), external hacking attacks, exceeding of traffic capacity, or software errors of the network node (404). The communication failure (550) may cause the link (440) to be disconnected. For example, due to the communication failure (550), the network node (401) may not be able to receive downlink traffic transmitted from the network node (404) through the first port (411). For example, the network node (401) may not be able to transmit uplink traffic to the network node (404) through the first port (411).

[0092] According to one embodiment, the network node (401) can identify or determine that the connection status of the network node (401) (or the first port (411)) is abnormal. For example, the network node (401) can identify or determine that the connection status of the first port (411) is abnormal by using a network management protocol (e.g., SNMP (simple network management protocol), ICMP (internet control message protocol)). For example, the network node (401) can identify or determine that the connection status of the first port (411) is abnormal based on the determination that no link signal is detected. For example, the network node (401) can receive downlink traffic for the network node (401) from the network node (402) through the second port (412) based on the determination that the connection status of the network node (401) is abnormal. For example, the network node (401) can transmit or provide uplink traffic for the network node (401) to the network node (402) through the second port (412) based on the determination that the connection status of the network node (401) is abnormal.

[0093] According to one embodiment, a network node (401) may transmit a status message to a network node (402) through a second port (412). The status message may indicate the connection status of the network node (401). For example, the status message may include the connection status of the first port (411) of the network node (401). For example, the status message may indicate the status of the second port (412) of the network node (401). For example, the status message may indicate that the connection status of the first port (411) is abnormal.

[0094] As a non-limiting example, the network node (401) may output a status message of the network node (401) only through the second port (412) among the first port (411) and the second port (412). The network node (401) may refrain from outputting a status message of the network node (401) through the first port (411). By refraining from outputting a status message of the network node (401) through the first port (411), the network node (401) may prevent a looping problem. For example, a looping problem may be referred to as causing performance degradation of the network by infinitely repeating the transmission of data (e.g., status message) along a circular path in the network.

[0095] According to one embodiment, a status message of a network node (401) may be transmitted to a network node (402) via a link (541). The network node (402) may receive a status message of the network node (401) from the network node (401) via a second port (422). The network node (402) may identify the connection status of the network node (401) based on the acquired status message of the network node (401). For example, the network node (402) may identify or determine that the connection status of the network node (401) is abnormal.

[0096] The network node (402) can identify or determine that the connection status of the network node (402) (or the first port (421)) is normal. The network node (402) can identify that downlink traffic for the network node (401) is being transmitted from the network node (404) via the link (531). For example, the network node (402) can receive downlink traffic for the network node (401) from the network node (404) via the first port (421). For example, the network node (402) can provide, deliver, or transmit the acquired downlink traffic for the network node (401) to the network node (401) via the second port (422). For example, downlink traffic for a network node (401) can be transmitted through a link (541) from a second port (422) of a network node (402) to a second port (412) of a network node (401). For example, a network node (401) can obtain or receive downlink traffic for a network node (401) from a network node (402) through the second port (412).

[0097] According to one embodiment, the network node (402) can identify or determine that the connection status of the network node (402) (or the first port (421)) is normal. The network node (402) can identify the connection status of the network node (401) based on the status message of the network node (401) obtained. For example, the network node (402) can identify or determine that the connection status of the network node (401) is abnormal. For example, the network node (402) can identify that uplink traffic for the network node (401) is to be transmitted from the network node (401) through the link (541). For example, the network node (402) can receive uplink traffic for the network node (401) from the network node (401) through the second port (422). For example, the network node (402) can provide, deliver, or transmit uplink traffic for the acquired network node (401) to the network node (404) through the first port (421). For example, uplink traffic for the network node (401) can be delivered from the first port (421) of the network node (402) to the network node (404) through the link (531).

[0098] As an example not limited to but not illustrated in FIG. 5b, a communication failure (e.g., communication failure (550)) may occur in the link (531). For example, due to a communication failure in the link (531), the network node (402) may not be able to receive downlink traffic transmitted from the network node (404) through the first port (421). For example, the network node (402) may not be able to transmit downlink traffic to the network node (404) through the first port (421). For example, the network node (402) may identify or determine that the connection status of the network node (402) (or the first port (421)) is abnormal. The network node (402) may provide or transmit a status message of the network node (402) to the network node (401) through the second port (422). According to one embodiment, a network node (401) may identify or determine that the connection status of a network node (402) is abnormal based on a status message of a network node (402). For example, the network node (401) may identify that downlink traffic for the network node (402) is to be transmitted from the network node (404) via a link (440). For example, the network node (401) may receive downlink traffic for the network node (402) from the network node (404) via a first port (411). For example, the network node (401) may provide, deliver, or transmit the acquired downlink traffic for the network node (402) to the network node (402) via a second port (412). For example, downlink traffic for a network node (402) can be transmitted from the second port (412) of a network node (401) to the second port (422) of a network node (402) via a link (541).For example, the network node (402) can obtain or receive downlink traffic for the network node (402) from the network node (401) through the second port (422).

[0099] Although not illustrated in FIG. 5b, a communication failure (e.g., communication failure (550)) may occur in the link (531). For example, the network node (401) may identify or determine that the connection status of the network node (402) is abnormal based on a status message obtained from the network node (402). For example, the network node (401) may identify that uplink traffic for the network node (402) is to be transmitted from the network node (402) through the link (541). For example, the network node (401) may receive uplink traffic for the network node (402) from the network node (402) through the second port (412). For example, the network node (401) may provide, deliver, or transmit the obtained uplink traffic for the network node (402) to the network node (404) through the first port (411). For example, uplink traffic for a network node (402) can be transmitted from the first port (411) of a network node (401) to a network node (404) via a link (440).

[0100] According to one embodiment, network nodes (401, 402) with redundant connections implemented as illustrated in FIGS. 5a and 5b can communicate with network node (404) even if a communication failure (e.g., communication failure (550)) occurs in link (440) or a communication failure (e.g., communication failure (550)) occurs in link (531). The stability of the network with redundant connections illustrated in FIGS. 5a and 5b may be higher than the stability of the network with a serial connection structure illustrated in FIG. 4.

[0101] FIGS. 6a to 6f illustrate examples of the connection status of network nodes resulting from a communication failure in a link.

[0102] Referring to FIG. 6a, the connection state of each of the network nodes (601, 602, 603, 604) may be normal. Network node (601), network node (602), and / or network node (603) may be connected in series. A redundant connection may be implemented between the group of network nodes (601, 602, 603) and network node (604). The network nodes (601, 602, 603, 604, 605) illustrated in FIG. 6a are merely one embodiment and the present disclosure is not limited thereto. Network nodes not illustrated in FIG. 6a (e.g., network node (301)) may be further connected in series between network node (602) and network node (603). For example, network nodes further connected in series between network node (602) and network node (603) can operate substantially the same as network node (602). According to one embodiment, the configuration in which network node (601), network node (602), network node (603), and network node (605) are connected may correspond to the configuration in which network node (401), network node (402), network node (403), and network node (404) are connected in FIG. 4. For example, network node (601) may correspond to network node (401) in FIG. 4. For example, network node (602) may correspond to network node (402) in FIG. 4. For example, network node (603) may correspond to network node (403) in FIG. 4. For example, network node (604) may correspond to network node (404) in FIG. 4.

[0103] According to one embodiment, each of the network node (601) and the network node (602) can identify that the second port of the network node is connected to the first port of the external network node. For example, the network node (601) can identify that the second port (612) of the network node (601) is connected to the first port (621) of the network node (602). In one embodiment, when the second port (622) of the network node (602) is connected to the first port (631) of the network node (603), download traffic from the network node (602) to the network node (601) through the second port (612) may not be transmitted. For example, the network node (602) can identify that the second port (622) of the network node (602) is connected to the first port (631) of the network node (603). In one embodiment, when the second port (622) of network node (602) is connected to the first port (631) of network node (603), download traffic from network node (603) to network node (602) through the second port (622) may not be transmitted. However, the embodiments are not limited. According to one embodiment, the configuration in which a group of network nodes (601, 602, 603), network node (604), and network node (605) are connected may correspond to the configuration in which network node (401), network node (402), and network node (404) are connected in FIG. 5A. For example, the group of network nodes (601, 602, 603) may correspond to network node (401) in FIG. 5A. For example, network node (604) may correspond to network node (402) in FIG. 5A. For example, the network node (605) can correspond to the network node (404) of FIG. 5a.

[0104] According to one embodiment, each of the network node (603) and the network node (604) can identify that the second port of the network node is connected to the second port of the external network node. For example, the network node (603) can identify that the second port (632) of the network node (603) is connected to the second port (642) of the network node (604). In one embodiment, when the second port (632) of the network node (603) is connected to the second port (642) of the network node (604), download traffic can be transmitted from the network node (604) to the network node (603) through the second port (632). For example, the network node (604) can identify that the second port (642) of the network node (604) is connected to the second port (632) of the network node (603). In one embodiment, when the second port (642) of the network node (604) is connected to the second port (632) of the network node (603), download traffic may be transmitted from the network node (603) to the network node (604) through the second port (642). However, the embodiments are not limited.

[0105] A network node (601) may be an example of a network node (301) of FIG. 3. A first port (611) of a network node (601) may be an example of a first port (321) of FIG. 3. A second port (612) of a network node (601) may be an example of a second port (322) of FIG. 3. A network node (601) may be connected to a network node (605) through the first port (611). For example, the first port (611) may be connected to a port of a network node (605). For example, the first port (611) and the network node (605) may be connected via a link (651). The network node (601) and the network node (605) may be physically or logically connected via the link (651) and may transmit or receive traffic (or data). For example, the link (651) may include a fronthaul and / or a backhaul. For example, the link (651) may be referred to as an external link and / or a hot link.

[0106] A network node (601) can be connected to a network node (602) through a second port (612). For example, the second port (612) can be connected to a first port (621) of the network node (602). For example, the second port (612) and the first port (621) of the network node (602) can be connected via a link (660). The network node (601) and the network node (602) can be connected via the link (660). For example, the link (660) can be referred to as a chained link.

[0107] According to one embodiment, a network node (601) can identify the connection status of the network node (601) as normal. The network node (601) can provide, deliver, or transmit a status message containing the connection status of the network node (601) to the network node (602) through the second port (612). For example, the network node (601) can receive a response message regarding the status message from the network node (602) through the second port (612). For example, the network node (601) can identify or determine that the network node (602) is connected to the second port (612) based on the response message.

[0108] According to one embodiment, a network node (601) may receive or obtain downlink traffic from a network node (605) through the first port (611) based on a determination that the connection state of the network node (601) (or the first port (611)) is normal. For example, downlink traffic may be transmitted to the network node (601) through a link (651). For example, the network node (601) may receive downlink traffic for each of the network nodes (601, 602, 603). For example, downlink traffic for each of the network nodes (601, 602, 603) may include address information for each of the network nodes (601, 602, 603).

[0109] Network node (601) may deliver, provide, or transmit downlink traffic for network node (602) and / or downlink traffic for network node (603) to network node (602) through the second port (612) based on the determination that the connection state of network node (601) (or the first port (611)) is normal. For example, downlink traffic for network node (602) and / or downlink traffic for network node (603) may be delivered or transmitted to network node (602) through the link (660).

[0110] According to one embodiment, a network node (601) may transmit or provide uplink traffic to a network node (605) through the first port (611) upon determining that the connection state of the network node (601) (or the first port (611)) is normal. For example, the uplink traffic may be transmitted to the network node (605) through the link (651). For example, the network node (601) may transmit uplink traffic for the network node (601) to the network node (605) through the first port (611). For example, the uplink traffic for the network node (601) may include address information of the network node (601).

[0111] A network node (601) may receive uplink traffic for a network node (602) and / or uplink traffic for a network node (603) from a network node (602) through a second port (612) based on the determination that the connection state of the network node (601) (or the first port (611)) is normal. For example, uplink traffic for a network node (602) may include address information of the network node (602). For example, uplink traffic for a network node (603) may include address information of the network node (603). A network node (601) may deliver, provide, or transmit uplink traffic for a network node (602) and uplink traffic for a network node (603) to a network node (605) through the first port (611). For example, in response to receiving or acquiring uplink traffic for network node (602) and / or uplink traffic for network node (603) from network node (602), network node (601) may deliver, provide, or transmit uplink traffic for network node (602) and / or uplink traffic for network node (603) to network node (605) through the first port (611). For example, uplink traffic for network node (602) and / or uplink traffic for network node (603) may be delivered or transmitted to network node (605) through the link (651).

[0112] A network node (602) may be an example of a network node (301) of FIG. 3. A first port (621) of a network node (602) may be an example of a first port (321) of FIG. 3. A second port (622) of a network node (602) may be an example of a second port (322) of FIG. 3. A network node (602) may be connected to a network node (601) through a first port (621). For example, a first port (621) may be connected to a second port (612) of a network node (601). For example, a first port (621) and a second port (612) of a network node (601) may be connected via a link (660). A network node (602) may be connected to a network node (603) through a second port (622). For example, the second port (622) may be connected to the first port (631) of the network node (603). For example, the second port (622) and the first port (631) of the network node (603) may be connected via a link (670). The network node (602) and the network node (603) may be physically or logically connected via the link (670) and may transmit or receive traffic (or data). For example, the link (670) may be referred to as a chained link.

[0113] According to one embodiment, a network node (602) may receive or obtain a status message of a network node (601) from a network node (601) through a first port (621). For example, the status message of the network node (601) may indicate that the connection status of the network node (601) (or the first port (611)) is normal. Based on the status message of the network node (601), the network node (602) may identify the connection status of the network node (602) (or the first port (621)) as normal.

[0114] According to one embodiment, a network node (602) may provide, deliver, or transmit a status message including the connection status of the network node (602) to a network node (603) through a second port (622). For example, the network node (602) may receive a response message regarding the status message from the network node (603) through the second port (622). For example, the network node (601) may identify or determine that the network node (602) is connected to the second port (612) based on the response message.

[0115] According to one embodiment, a network node (602) may receive or obtain downlink traffic from a network node (601) through the first port (621) upon determining that the connection state of the network node (602) (or the first port (621)) is normal. For example, downlink traffic may be transmitted to the network node (602) through the link (660). For example, the network node (602) may receive or obtain downlink traffic for the network node (602) and downlink traffic for the network node (603) from the network node (601) through the first port (621). For example, downlink traffic for the network node (602) may include address information of the network node (602). Downlink traffic for the network node (603) may include address information of the network node (603).

[0116] According to one embodiment, the network node (602) may deliver, provide, or transmit downlink traffic for the network node (603) to the network node (603) through the second port (622) upon determining that the connection state of the network node (602) (or the first port (621)) is in a normal state. For example, the network node (602) may deliver, provide, or transmit downlink traffic for the network node (603) to the network node (603) through the second port (622) in response to receiving or acquiring downlink traffic for the network node (603). For example, downlink traffic for the network node (603) may be delivered or transmitted to the network node (603) through the link (670).

[0117] According to one embodiment, the network node (602) may transmit or provide uplink traffic to the network node (601) through the first port (621) upon determining that the connection state of the network node (602) (or the first port (621)) is normal. For example, the uplink traffic may be transmitted to the network node (601) through the link (660). For example, the network node (602) may transmit uplink traffic for the network node (602) to the network node (601) through the first port (621). For example, the uplink traffic for the network node (602) may include address information of the network node (602).

[0118] Network node (602) can receive uplink traffic for network node (603) from network node (603) through the second port (622) upon determining that the connection state of network node (602) (or the first port (621)) is normal. For example, uplink traffic for network node (603) may include address information of network node (603). Network node (602) can deliver, provide, or transmit uplink traffic for network node (603) to network node (601) through the first port (621). For example, network node (602) can deliver, provide, or transmit uplink traffic for network node (603) to network node (601) through the first port (621) in response to receiving or acquiring uplink traffic for network node (603) from network node (603). For example, uplink traffic for a network node (603) can be transmitted to or sent to a network node (601) via a link (660).

[0119] A network node (603) may be an example of a network node (301) of FIG. 3. A first port (631) of a network node (603) may be an example of a first port (321) of FIG. 3. A second port (632) of a network node (603) may be an example of a second port (322) of FIG. 3. A network node (603) may be connected to a network node (602) through a first port (631). For example, a first port (631) may be connected to a second port (622) of a network node (602). For example, a first port (631) and a second port (622) of a network node (602) may be connected via a link (670). A network node (603) may be connected to a network node (604) through a second port (632). For example, the second port (632) may be connected to the second port (642) of the network node (604). For example, the second port (632) and the second port (642) of the network node (604) may be connected via a link (680). For example, the network node (603) and the network node (604) may be physically or logically connected via the link (680) and may transmit or receive traffic (or data). For example, the link (680) may be referred to as a standby link.

[0120] According to one embodiment, a network node (603) may receive or obtain a status message of a network node (602) from a network node (602) through a first port (631). For example, the status message of the network node (602) may indicate that the connection status of the network node (602) (or the first port (621)) is normal. A network node (603) may receive or obtain a status message of a network node (604) from a network node (604) through a second port (632). For example, the status message of the network node (604) may indicate that the connection status of the network node (604) (or the first port (641)) is normal. A network node (603) may identify the connection status of the network node (603) (or the first port (631)) as normal based on the status message of the network node (602) and / or the status message of the network node (604).

[0121] According to one embodiment, the network node (603) may provide, deliver, or transmit a status message including the connection status of the network node (603) to the network node (604) through the second port (632).

[0122] According to one embodiment, the network node (603) may receive or obtain downlink traffic for the network node (603) from the network node (602) through the first port (631) upon determining that the connection state of the network node (603) (or the first port (631)) is in a normal state. For example, downlink traffic for the network node (603) may be transmitted to the network node (603) through the link (670). For example, downlink traffic for the network node (603) may include address information of the network node (603).

[0123] According to one embodiment, the network node (603) may transmit or provide uplink traffic to the network node (602) through the first port (631) upon determining that the connection state of the network node (603) (or the first port (631)) is normal. For example, the uplink traffic may be transmitted to the network node (602) through the link (670). For example, the network node (603) may transmit uplink traffic for the network node (603) to the network node (602) through the first port (631). For example, the uplink traffic for the network node (603) may include address information of the network node (603).

[0124] A network node (604) may be an example of a network node (301) of FIG. 3. A first port (641) of a network node (604) may be an example of a first port (321) of FIG. 3. A second port (642) of a network node (604) may be an example of a second port (322) of FIG. 3. A network node (604) may be connected to a network node (605) through the first port (641). For example, the first port (641) may be connected to a port of a network node (605). For example, the first port (641) and the network node (605) may be connected via a link (652). For example, the link (652) may include a fronthaul and / or backhaul. For example, the link (652) may be referred to as an external link and / or a hot link.

[0125] A network node (604) may be connected to a network node (603) via a second port (642). For example, the second port (642) may be connected to a second port (632) of a network node (603). For example, the second port (642) and the second port (632) of a network node (603) may be connected via a link (680). The network node (603) and the network node (604) may be physically or logically connected via the link (680) and may transmit or receive traffic (or data).

[0126] According to one embodiment, the network node (604) can identify or determine that the connection status of the network node (604) (or the first port (641)) is normal. For example, the network node (604) can provide, transmit, or forward a status message of the network node (604) to the network node (603) through the second port (642). For example, the status message of the network node (604) may indicate that the connection status of the network node (604) (the first port (641)) is normal.

[0127] According to one embodiment, the network node (604) may obtain or receive a status message of the network node (603) from the network node (603) through the second port (642). For example, the status message of the network node (603) may indicate that the connection status of the network node (603) (or the first port (631)) is normal.

[0128] According to one embodiment, the network node (604) may receive or obtain downlink traffic from the network node (605) through the first port (641) based on the determination that the connection state of the network node (604) (or the first port (641)) is normal. For example, downlink traffic may be transmitted to the network node (604) through the link (652). For example, the network node (604) may receive downlink traffic for the network node (604). For example, downlink traffic for the network node (604) may include address information of the network node (604).

[0129] According to one embodiment, the network node (604) may transmit or provide uplink traffic to the network node (605) through the first port (641) upon determining that the connection state of the network node (603) (or the first port (631)) is normal. For example, the uplink traffic may be transmitted to the network node (605) through the link (652). For example, the network node (604) may transmit uplink traffic for the network node (604) to the network node (605) through the first port (641).

[0130] A network node (605) may be an example of a network node (301) of FIG. 3. A network node (605) may include a network node (404) of FIG. 4 to 5b. For example, a network node (605) may be configured to deliver or transmit downlink traffic (or data) transmitted from a core network to a network node corresponding to address information included in the downlink traffic. For example, a network node (605) may be included in a higher layer than network nodes (601, 602, 603, 604). For example, network nodes (601, 602, 603, 604) may correspond to a DU (or RU), and a network node (605) may correspond to a CU. As another example, a network node (605) may be connected to a CU. For example, a network node (605) may include a switch (or router) connected to a CU. For example, a network node (605) may be used to transmit or forward downlink traffic transmitted from a CU to a network node corresponding to address information included in the downlink traffic. For example, the network node (605) may identify a forwarding path for transmitting to a network node corresponding to address information included in the downlink traffic. For example, to identify a forwarding path, the network node (605) may use an address table (e.g., MAC address table) stored within the network node (605).

[0131] According to one embodiment, a network node (605) may decide to transmit downlink traffic for each of the network nodes (601, 602, 603) through link (651) among link (651) and link (652). For example, the network node (605) may transmit downlink traffic for each of the network nodes (601, 602, 603) through link (651). The network node (605) may decide to transmit downlink traffic for the network node (604) through link (652) among link (651) and link (652). For example, the network node (605) may transmit downlink traffic for the network node (604) through link (652).

[0132] According to one embodiment, a network node (605) can identify that downlink traffic for some of the network nodes (601, 602, 603) cannot be transmitted through the link (651) in the event of a communication failure to be described later. For example, the network node (605) can identify that downlink traffic cannot be transmitted through the link (651) by using a network management protocol. For example, the network node (605) can search for or identify the transmission path of the downlink traffic by using a flooding method. For example, the network node (605) can obtain response traffic for the downlink traffic after outputting the downlink traffic through all ports of the network node (605). The network node (605) can update or identify the transmission path of the downlink traffic using the response traffic.

[0133] Referring to FIG. 6b, a communication failure (691) may occur at the link (651). For example, the link (651) may be shown as disconnected. The network node (601) may not be able to receive downlink traffic transmitted from the network node (605) through the first port (611). The network node (601) may not be able to transmit uplink traffic to the network node (605) through the first port (611). The network node (601) may identify or determine that the connection status of the network node (601) (or the first port (611)) is abnormal.

[0134] According to one embodiment, a network node (601) may acquire or receive downlink traffic transmitted from a network node (605) through a second port (612) upon determining that the connection status of the network node (601) (or the first port (611)) is abnormal. For example, the network node (601) may acquire or receive downlink traffic for the network node (601) from the network node (602) through the second port (612). For example, downlink traffic for the network node (601) may be transmitted to the second port (612) of the network node (601) through links (652, 660, 670, 680).

[0135] According to one embodiment, a network node (601) may transmit, provide, or forward uplink traffic for the network node (601) to a network node (605) through a second port (612) upon determining that the connection status of the network node (601) (or the first port (611)) is abnormal. For example, the network node (601) may transmit, provide, or forward uplink traffic for the network node (601) to a network node (602) through the second port (612). For example, uplink traffic for the network node (601) may be forwarded to the network node (605) through links (652, 660, 670, 680).

[0136] According to one embodiment, the network node (601) may provide, deliver, or transmit a status message of the network node (601) to the network node (602) through the second port (612). For example, the status message of the network node (601) may indicate that the connection status of the network node (601) is abnormal.

[0137] Network node (602) may obtain or receive a status message of network node (601) from network node (601) through the first port (621). Network node (602) may identify or determine that the connection status of network node (602) (or the first port (621)) is abnormal based on the status message of network node (601). Network node (602) may not be able to receive downlink traffic transmitted from network node (605) through the first port (621). Network node (602) may not be able to transmit uplink traffic to network node (605) through the first port (621).

[0138] According to one embodiment, the network node (602) may acquire or receive downlink traffic transmitted from the network node (605) through the second port (622) upon determining that the connection status of the network node (602) (or the first port (621)) is abnormal. For example, the network node (602) may acquire or receive downlink traffic for the network node (602) from the network node (603) through the second port (622). For example, downlink traffic for the network node (602) may be transmitted to the second port (622) of the network node (602) through links (652, 670, 680).

[0139] According to one embodiment, the network node (602) may acquire or receive downlink traffic for the network node (601) from the network node (603) through the second port (622) upon determining that the connection state of the network node (602) (or the first port (621)) is abnormal. The network node (602) may provide, deliver, or transmit downlink traffic for the network node (601) to the network node (601) through the first port (621).

[0140] According to one embodiment, the network node (602) may transmit, provide, or forward uplink traffic for the network node (602) to the network node (605) through the second port (622) upon determining that the connection status of the network node (602) (or the first port (621)) is abnormal. For example, the network node (602) may transmit, provide, or forward uplink traffic for the network node (602) to the network node (603) through the second port (622). For example, uplink traffic for the network node (602) may be forwarded to the network node (605) through links (652, 670, 680).

[0141] According to one embodiment, the network node (602) may acquire or receive uplink traffic for the network node (601) from the network node (601) through the first port (621) upon determining that the connection state of the network node (602) (or the first port (621)) is abnormal. The network node (602) may provide, deliver, or transmit the uplink traffic for the network node (601) to the network node (603) through the second port (622).

[0142] According to one embodiment, the network node (602) may provide, deliver, or transmit a status message of the network node (602) to the network node (603) through the second port (622). For example, the status message of the network node (602) may indicate that the connection status of the network node (602) is abnormal.

[0143] Network node (603) may obtain or receive a status message of network node (602) from network node (602) through the first port (631). Network node (603) may identify or determine that the connection status of network node (603) (or the first port (631)) is abnormal based on the status message of network node (602). Network node (603) may not be able to receive downlink traffic transmitted from network node (605) through the first port (631). Network node (603) may not be able to transmit uplink traffic to network node (605) through the first port (631).

[0144] According to one embodiment, the network node (602) may obtain or receive a status message of the network node (604) from the network node (604) through the second port (632). For example, the status message of the network node (604) may indicate that the connection status of the network node (604) (or the first port (641)) is normal.

[0145] According to one embodiment, the network node (603) may acquire or receive downlink traffic transmitted from the network node (605) through the second port (632) upon determining that the connection status of the network node (603) (or the first port (631)) is abnormal. For example, the network node (603) may acquire or receive downlink traffic for the network node (603) from the network node (604) through the second port (632). For example, downlink traffic for the network node (603) may be transmitted to the second port (632) of the network node (603) through links (652, 680).

[0146] According to one embodiment, a network node (603) may acquire or receive downlink traffic for each of the network nodes (601, 602) from a network node (604) through a second port (632) upon determining that the connection state of the network node (603) (or the first port (631)) is abnormal. The network node (603) may provide, deliver, or transmit downlink traffic for each of the network nodes (601, 602) to the network node (602) through the first port (631).

[0147] According to one embodiment, the network node (603) may transmit, provide, or forward uplink traffic for the network node (603) to the network node (605) through the second port (632) upon determining that the connection status of the network node (603) (or the first port (631)) is abnormal. For example, the network node (603) may transmit, provide, or forward uplink traffic for the network node (603) to the network node (604) through the second port (632). For example, uplink traffic for the network node (603) may be forwarded to the network node (605) through links (652, 680).

[0148] According to one embodiment, a network node (603) may acquire or receive uplink traffic for each of the network nodes (601, 602) from a network node (602) through the first port (631) upon determining that the connection state of the network node (603) (or the first port (631)) is abnormal. The network node (603) may provide, deliver, or transmit uplink traffic for each of the network nodes (601, 602) to a network node (604) through the second port (632).

[0149] According to one embodiment, the network node (603) may provide, deliver, or transmit a status message of the network node (603) to the network node (604) through the second port (632). For example, the status message of the network node (603) may indicate that the connection status of the network node (603) is abnormal.

[0150] The network node (604) can identify that the connection status of the network node (604) (or the first port (641)) is normal. Since the operations of the network node (604) in a normal connection status may be substantially the same as the operations of the network node (604) in FIG. 6a, redundant descriptions are omitted. For example, for the network node (604) in a normal connection status, the descriptions of the network node (604) in FIG. 6a may be referenced.

[0151] According to one embodiment, the network node (604) can obtain or receive a status message of the network node (603) from the network node (603) through the second port (642). The network node (604) can identify that the connection status of the network node (603) is abnormal.

[0152] According to one embodiment, the network node (604) can receive or obtain downlink traffic for the network node (604) from the network node (605) through the first port (641) based on the determination that the connection state of the network node (604) (or the first port (641)) is normal.

[0153] According to one embodiment, the network node (604) may transmit or provide uplink traffic for the network node (604) to the network node (605) through the first port (641) upon determining that the connection state of the network node (604) (or the first port (641)) is normal.

[0154] According to one embodiment, a network node (604) may acquire or receive downlink traffic for each of the network nodes (601, 602, 603) from a network node (605) through the first port (641) upon determining that the connection state of the network node (604) (or the first port (641)) is in a normal state. The network node (604) may provide, deliver, or transmit downlink traffic for each of the network nodes (601, 602, 603) to the network node (603) through the second port (642).

[0155] According to one embodiment, a network node (604) may acquire or receive uplink traffic for each of the network nodes (601, 602, 603) from a network node (603) via a second port (642) upon determining that the connection state of the network node (604) (or the first port (641)) is in a normal state. The network node (604) may provide, deliver, or transmit uplink traffic for each of the network nodes (601, 602, 603) to a network node (605) via the first port (641).

[0156] A network node (605) may decide to transmit downlink traffic for each of the network nodes (601, 602, 603) via link (652) among link (651) and link (652) due to a communication failure (691) occurring in link (651). For example, the network node (605) may transmit downlink traffic for each of the network nodes (601, 602, 603) via link (652). The network node (605) may decide to transmit downlink traffic for the network node (604) via link (652) among link (651) and link (652). For example, the network node (605) may transmit downlink traffic for the network node (604) via link (652).

[0157] Referring to FIG. 6c, a communication failure (692) may occur in the link (660). For example, the link (660) may be shown as disconnected.

[0158] According to one embodiment, the network node (601) can identify that the connection status of the network node (601) (or the first port (611)) is normal. Since the operations of the network node (601) in a normal connection status may be substantially the same as the operations of the network node (601) of FIG. 6a, redundant descriptions are omitted. For example, for the network node (601) in a normal connection status, the descriptions of the network node (601) of FIG. 6a may be referenced.

[0159] According to one embodiment, the network node (601) may acquire or receive downlink traffic for the network node (601) from the network node (605) through the first port (611) based on the determination that the connection state of the network node (601) (or the first port (611)) is in a normal state. The network node (601) may transmit, provide, or deliver uplink traffic for the network node (601) to the network node (605) through the first port (611) based on the determination that the connection state of the network node (601) (or the first port (611)) is in a normal state.

[0160] According to one embodiment, the network node (601) may output a status message of the network node (601) through the second port (612). For example, the status message of the network node (601) may not be delivered to the network node (602) due to a communication failure (692). Additionally, the network node (601) may not receive a response message for the status message of the network node (601).

[0161] Network node (602) may not receive status messages from network node (601) through the first port (621) due to a communication failure (692). For example, network node (602) may identify or determine that the connection status of network node (602) is abnormal as the status message of network node (601) is not received. For example, network node (602) may identify or determine that the connection status of network node (602) is abnormal as the reception of status messages from network node (601) is interrupted. Network node (602) may not be able to receive downlink traffic transmitted from network node (605) through the first port (621). Network node (602) may not be able to transmit uplink traffic to network node (605) through the first port (621).

[0162] According to one embodiment, the operations of a network node (602) in an abnormal connection state may be substantially the same as the operations of the network node (602) of FIG. 6b, so redundant descriptions are omitted. For example, for a network node (602) in an abnormal connection state, the descriptions of the network node (602) of FIG. 6b may be referenced.

[0163] According to one embodiment, the network node (602) may acquire or receive downlink traffic transmitted from the network node (605) through the second port (622) upon determining that the connection status of the network node (602) (or the first port (621)) is abnormal. For example, the network node (602) may acquire or receive downlink traffic for the network node (602) from the network node (603) through the second port (622).

[0164] According to one embodiment, the network node (602) may transmit, provide, or forward uplink traffic for the network node (602) to the network node (605) through the second port (622) upon determining that the connection status of the network node (602) (or the first port (621)) is abnormal. For example, the network node (602) may transmit, provide, or forward uplink traffic for the network node (602) to the network node (603) through the second port (622).

[0165] According to one embodiment, the network node (602) may provide, deliver, or transmit a status message of the network node (602) to the network node (603) through the second port (622). For example, the status message of the network node (602) may indicate that the connection status of the network node (602) is abnormal.

[0166] Network node (603) may obtain or receive a status message of network node (602) from network node (602) through the first port (631). Network node (603) may identify or determine that the connection status of network node (603) (or the first port (631)) is abnormal based on the status message of network node (602). Network node (603) may not be able to receive downlink traffic transmitted from network node (605) through the first port (631). Network node (603) may not be able to transmit uplink traffic to network node (605) through the first port (631).

[0167] According to one embodiment, the operations of a network node (603) in an abnormal connection state may be substantially the same as the operations of the network node (603) of FIG. 6b, so redundant descriptions are omitted. For example, for a network node (603) in an abnormal connection state, the descriptions of the network node (603) of FIG. 6b may be referenced.

[0168] According to one embodiment, the network node (603) may acquire or receive downlink traffic transmitted from the network node (605) through the second port (632) upon determining that the connection status of the network node (603) (or the first port (631)) is abnormal. For example, the network node (603) may acquire or receive downlink traffic for the network node (603) from the network node (604) through the second port (632).

[0169] According to one embodiment, the network node (603) may acquire or receive downlink traffic for the network node (602) from the network node (604) through the second port (632) upon determining that the connection status of the network node (603) (or the first port (631)) is abnormal. The network node (603) may provide, deliver, or transmit downlink traffic for the network node (602) to the network node (602) through the first port (631).

[0170] According to one embodiment, the network node (603) may transmit, provide, or forward uplink traffic for the network node (603) to the network node (605) through the second port (632) upon determining that the connection status of the network node (603) (or the first port (631)) is abnormal. For example, the network node (603) may transmit, provide, or forward uplink traffic for the network node (603) to the network node (604) through the second port (632).

[0171] According to one embodiment, the network node (603) may acquire or receive uplink traffic for the network node (602) from the network node (602) through the first port (631) upon determining that the connection state of the network node (603) (or the first port (631)) is abnormal. The network node (603) may provide, deliver, or transmit the uplink traffic for the network node (602) to the network node (604) through the second port (632).

[0172] According to one embodiment, the network node (603) may provide, deliver, or transmit a status message of the network node (603) to the network node (604) through the second port (632). For example, the status message of the network node (603) may indicate that the connection status of the network node (603) is abnormal.

[0173] The network node (604) can identify that the connection status of the network node (604) (or the first port (641)) is normal. Since the operations of the network node (604) in a normal connection status may be substantially the same as the operations of the network node (604) in FIG. 6a, redundant descriptions are omitted. For example, for the network node (604) in a normal connection status, the descriptions of the network node (604) in FIG. 6a may be referenced.

[0174] According to one embodiment, the network node (604) can receive or obtain downlink traffic for the network node (604) from the network node (605) through the first port (641) based on the determination that the connection state of the network node (604) (or the first port (641)) is normal.

[0175] According to one embodiment, the network node (604) may transmit or provide uplink traffic for the network node (604) to the network node (605) through the first port (641) upon determining that the connection state of the network node (603) (or the first port (631)) is normal.

[0176] According to one embodiment, a network node (604) may acquire or receive downlink traffic for each of the network nodes (602, 603) from a network node (605) through the first port (641) upon determining that the connection state of the network node (604) (or the first port (641)) is normal. The network node (604) may provide, deliver, or transmit downlink traffic for each of the network nodes (602, 603) to the network node (603) through the second port (642).

[0177] According to one embodiment, a network node (604) may acquire or receive uplink traffic for each of the network nodes (602, 603) from the network node (603) through the first port (641) upon determining that the connection state of the network node (604) (or the first port (641)) is in a normal state. The network node (604) may provide, deliver, or transmit uplink traffic for each of the network nodes (602, 603) to the network node (605) through the second port (622).

[0178] A network node (605) may decide to transmit downlink traffic for a network node (601) through link (651) among link (651) and link (652). For example, a network node (605) may transmit downlink traffic for a network node (601) through link (651).

[0179] According to one embodiment, a network node (605) may decide to transmit downlink traffic for each of the network nodes (602, 603, 604) through link (652) among link (651) and link (652) due to a communication failure (692) occurring in link (660). For example, the network node (605) may transmit downlink traffic for each of the network nodes (602, 603, 604) through link (652).

[0180] Referring to FIG. 6d, a communication failure (693) may occur in the link (670). For example, the link (670) may be shown as disconnected.

[0181] According to one embodiment, the network node (601) can identify that the connection status of the network node (601) (or the first port (611)) is normal. Since the operations of the network node (601) in a normal connection status may be substantially the same as the operations of the network node (601) of FIG. 6a, redundant descriptions are omitted. For example, for the network node (601) in a normal connection status, the descriptions of the network node (601) of FIG. 6a may be referenced.

[0182] According to one embodiment, the network node (601) may acquire or receive downlink traffic for the network node (601) from the network node (605) through the first port (611) based on the determination that the connection state of the network node (601) (or the first port (611)) is in a normal state. The network node (601) may transmit, provide, or deliver uplink traffic for the network node (601) to the network node (605) through the first port (611) based on the determination that the connection state of the network node (601) (or the first port (611)) is in a normal state.

[0183] The network node (602) can identify that the connection status of the network node (602) (or the first port (621)) is normal. Since the operations of the network node (602) in a normal connection status may be substantially the same as the operations of the network node (602) in FIG. 6a, redundant descriptions will be omitted.

[0184] According to one embodiment, the network node (602) may acquire or receive downlink traffic for the network node (602) from the network node (601) through the first port (621) based on the determination that the connection state of the network node (602) (or the first port (621)) is in a normal state. The network node (602) may transmit, provide, or deliver uplink traffic for the network node (602) to the network node (601) through the first port (611) based on the determination that the connection state of the network node (602) (or the first port (621)) is in a normal state.

[0185] According to one embodiment, the network node (602) may output a status message of the network node (602) through the second port (622). For example, the status message of the network node (602) may not be delivered to the network node (603) due to a communication failure (693). Additionally, the network node (602) may not receive a response message for the status message of the network node (602).

[0186] Network node (603) may not receive status messages from network node (602) from network node (602) through the first port (631). For example, network node (603) may identify or determine that the connection status of network node (602) is abnormal as the status message of network node (602) is not received. For example, network node (603) may identify or determine that the connection status of network node (603) is abnormal as the reception of status messages from network node (602) is interrupted. Network node (603) may not be able to receive downlink traffic transmitted from network node (605) through the first port (631). Network node (603) may not transmit uplink traffic to network node (605) through the first port (631).

[0187] According to one embodiment, the operations of a network node (603) in an abnormal connection state may be substantially the same as the operations of the network node (603) of FIG. 6b, so redundant descriptions are omitted. For example, for a network node (603) in an abnormal connection state, the descriptions of the network node (603) of FIG. 6b may be referenced.

[0188] According to one embodiment, the network node (603) may acquire or receive downlink traffic transmitted from the network node (605) through the second port (632) upon determining that the connection status of the network node (603) (or the first port (631)) is abnormal. For example, the network node (603) may acquire or receive downlink traffic for the network node (603) from the network node (604) through the second port (632).

[0189] According to one embodiment, the network node (603) may transmit, provide, or forward uplink traffic for the network node (603) to the network node (605) through the second port (632) upon determining that the connection status of the network node (603) (or the first port (631)) is abnormal. For example, the network node (603) may transmit, provide, or forward uplink traffic for the network node (603) to the network node (604) through the second port (632).

[0190] According to one embodiment, the network node (603) may provide, deliver, or transmit a status message of the network node (603) to the network node (604) through the second port (632). For example, the status message of the network node (603) may indicate that the connection status of the network node (603) is abnormal.

[0191] The network node (604) can identify that the connection status of the network node (604) (or the first port (641)) is normal. Since the operations of the network node (604) in a normal connection status may be substantially the same as the operations of the network node (604) in FIG. 6a, redundant descriptions are omitted. For example, for the network node (604) in a normal connection status, the descriptions of the network node (604) in FIG. 6a may be referenced.

[0192] According to one embodiment, the network node (604) can receive or obtain downlink traffic for the network node (604) from the network node (605) through the first port (641) based on the determination that the connection state of the network node (604) (or the first port (641)) is normal.

[0193] According to one embodiment, the network node (604) may transmit or provide uplink traffic for the network node (604) to the network node (605) through the first port (641) upon determining that the connection state of the network node (603) (or the first port (631)) is normal.

[0194] According to one embodiment, the network node (604) may acquire or receive downlink traffic for the network node (603) from the network node (605) through the first port (641) upon determining that the connection state of the network node (604) (or the first port (641)) is normal. The network node (604) may provide, deliver, or transmit downlink traffic for the network node (603) to the network node (603) through the second port (642).

[0195] According to one embodiment, the network node (604) may acquire or receive downlink traffic for the network node (603) from the network node (603) through the first port (641) upon determining that the connection state of the network node (604) (or the first port (641)) is normal. The network node (604) may provide, deliver, or transmit uplink traffic for the network node (603) to the network node (605) through the second port (622).

[0196] A network node (605) may decide to transmit downlink traffic for each of the network nodes (601, 602) through link (651) among link (651) and link (652). For example, a network node (605) may transmit downlink traffic for each of the network nodes (601, 602) through link (651).

[0197] According to one embodiment, a network node (605) may decide to transmit downlink traffic for each of the network nodes (603, 604) through link (652) among link (651) and link (652) due to a communication failure (693) occurring in link (670). For example, the network node (605) may transmit downlink traffic for each of the network nodes (603, 604) through link (652).

[0198] Referring to FIG. 6e, a communication failure (694) may occur in the link (680). For example, the link (680) may be shown as disconnected.

[0199] According to one embodiment, the network node (601) can identify that the connection status of the network node (601) (or the first port (611)) is normal. Since the operations of the network node (601) in a normal connection status may be substantially the same as the operations of the network node (601) of FIG. 6a, redundant descriptions are omitted. For example, for the network node (601) in a normal connection status, the descriptions of the network node (601) of FIG. 6a may be referenced.

[0200] According to one embodiment, the network node (601) may acquire or receive downlink traffic for the network node (601) from the network node (605) through the first port (611) based on the determination that the connection state of the network node (601) (or the first port (611)) is in a normal state. The network node (601) may transmit, provide, or deliver uplink traffic for the network node (601) to the network node (605) through the first port (611) based on the determination that the connection state of the network node (601) (or the first port (611)) is in a normal state.

[0201] The network node (602) can identify that the connection status of the network node (602) (or the first port (621)) is normal. Since the operations of the network node (602) in a normal connection status may be substantially the same as the operations of the network node (602) in FIG. 6a, redundant descriptions will be omitted.

[0202] According to one embodiment, the network node (602) may acquire or receive downlink traffic for the network node (602) from the network node (601) through the first port (621) based on the determination that the connection state of the network node (602) (or the first port (621)) is in a normal state. The network node (602) may transmit, provide, or deliver uplink traffic for the network node (602) to the network node (601) through the first port (611) based on the determination that the connection state of the network node (602) (or the first port (621)) is in a normal state.

[0203] The network node (603) can identify that the connection status of the network node (603) (or the first port (631)) is normal. Since the operations of the network node (603) in a normal connection status may be substantially the same as the operations of the network node (603) in FIG. 6a, redundant descriptions will be omitted.

[0204] According to one embodiment, the network node (603) may acquire or receive downlink traffic for the network node (603) from the network node (602) through the first port (631) based on the determination that the connection state of the network node (603) (or the first port (631)) is in a normal state. The network node (603) may transmit, provide, or deliver uplink traffic for the network node (603) to the network node (602) through the first port (631) based on the determination that the connection state of the network node (603) (or the first port (631)) is in a normal state.

[0205] According to one embodiment, the network node (603) may output a status message of the network node (603) through the second port (632). For example, the status message of the network node (603) may not be delivered to the network node (604) due to a communication failure (694). Additionally, the network node (603) may not receive a response message for the status message of the network node (603).

[0206] The network node (604) can identify that the connection status of the network node (604) (or the first port (641)) is normal. Since the operations of the network node (604) in a normal connection status may be substantially the same as the operations of the network node (604) in FIG. 6a, redundant descriptions are omitted. For example, for the network node (604) in a normal connection status, the descriptions of the network node (604) in FIG. 6a may be referenced.

[0207] According to one embodiment, the network node (604) can receive or obtain downlink traffic for the network node (604) from the network node (605) through the first port (641) based on the determination that the connection state of the network node (604) (or the first port (641)) is normal.

[0208] According to one embodiment, the network node (604) may transmit or provide uplink traffic for the network node (604) to the network node (605) through the first port (641) upon determining that the connection state of the network node (603) (or the first port (631)) is normal.

[0209] A network node (605) may decide to transmit downlink traffic for each of the network nodes (601, 602, 603) through link (651) among link (651) and link (652). For example, a network node (605) may transmit downlink traffic for each of the network nodes (601, 602, 603) through link (651).

[0210] According to one embodiment, the network node (605) may decide to transmit downlink traffic for the network node (604) through link (652) among link (651) and link (652). For example, the network node (605) may transmit downlink traffic for the network node (604) through link (652).

[0211] Referring to FIG. 6f, a communication failure (695) may occur in the link (652). For example, the link (652) may be shown as disconnected.

[0212] According to one embodiment, the network node (601) can identify that the connection status of the network node (601) (or the first port (611)) is normal. Since the operations of the network node (601) in a normal connection status may be substantially the same as the operations of the network node (601) of FIG. 6a, redundant descriptions are omitted. For example, for the network node (601) in a normal connection status, the descriptions of the network node (601) of FIG. 6a may be referenced.

[0213] According to one embodiment, the network node (601) may acquire or receive downlink traffic for the network node (601) from the network node (605) through the first port (611) based on the determination that the connection state of the network node (601) (or the first port (611)) is in a normal state. The network node (601) may transmit, provide, or deliver uplink traffic for the network node (601) to the network node (605) through the first port (611) based on the determination that the connection state of the network node (601) (or the first port (611)) is in a normal state.

[0214] The network node (602) can identify that the connection status of the network node (602) (or the first port (621)) is normal. Since the operations of the network node (602) in a normal connection status may be substantially the same as the operations of the network node (602) in FIG. 6a, redundant descriptions will be omitted.

[0215] According to one embodiment, the network node (602) may acquire or receive downlink traffic for the network node (602) from the network node (601) through the first port (621) based on the determination that the connection state of the network node (602) (or the first port (621)) is in a normal state. The network node (602) may transmit, provide, or deliver uplink traffic for the network node (602) to the network node (601) through the first port (611) based on the determination that the connection state of the network node (602) (or the first port (621)) is in a normal state.

[0216] The network node (603) can identify that the connection status of the network node (603) (or the first port (631)) is normal. Since the operations of the network node (603) in a normal connection status may be substantially the same as the operations of the network node (603) in FIG. 6a, redundant descriptions will be omitted.

[0217] According to one embodiment, the network node (603) may acquire or receive downlink traffic for the network node (603) from the network node (602) through the first port (631) based on the determination that the connection state of the network node (603) (or the first port (631)) is in a normal state. The network node (603) may transmit, provide, or deliver uplink traffic for the network node (603) to the network node (602) through the first port (631) based on the determination that the connection state of the network node (603) (or the first port (631)) is in a normal state.

[0218] According to one embodiment, the network node (603) may output a status message of the network node (603) through the second port (632). For example, the status message of the network node (603) may not be delivered to the network node (604) due to a communication failure (694). Additionally, the network node (603) may not receive a response message for the status message of the network node (603).

[0219] The network node (604) may not receive downlink traffic transmitted from the network node (605) through the first port (641) due to a communication failure (695) occurring in the link (652). The network node (604) may not transmit uplink traffic to the network node (605) through the first port (641). The network node (604) may identify or determine that the connection status of the network node (604) (or the first port (641)) is abnormal.

[0220] According to one embodiment, the network node (604) may acquire or receive downlink traffic transmitted from the network node (605) through the second port (642) upon determining that the connection status of the network node (604) (or the first port (641)) is abnormal. For example, the network node (604) may acquire or receive downlink traffic for the network node (604) from the network node (603) through the second port (642). For example, downlink traffic for the network node (604) may be transmitted to the second port (642) of the network node (604) through links (651, 660, 670, 680).

[0221] According to one embodiment, the network node (604) may transmit, provide, or forward uplink traffic for the network node (604) to the network node (605) through the second port (642) upon determining that the connection status of the network node (604) (or the first port (641)) is abnormal. For example, the network node (604) may transmit, provide, or forward uplink traffic for the network node (604) to the network node (603) through the second port (642). For example, uplink traffic for the network node (604) may be forwarded to the network node (605) through links (651, 660, 670, 680).

[0222] According to one embodiment, the network node (604) may provide, deliver, or transmit a status message of the network node (604) to the network node (603) through the second port (642). For example, the status message of the network node (604) may indicate that the connection status of the network node (604) is abnormal.

[0223] A network node (605) may decide to transmit downlink traffic for each of the network nodes (601, 602, 603) through link (651) among link (651) and link (652). For example, a network node (605) may transmit downlink traffic for each of the network nodes (601, 602, 603) through link (651).

[0224] According to one embodiment, a network node (605) may decide to transmit downlink traffic for a network node (604) through link (651) among link (651) and link (652) due to a communication failure (695) occurring in link (652). For example, the network node (605) may transmit downlink traffic for a network node (604) through link (651).

[0225] According to one embodiment, in 6b to 6f, a communication failure (e.g., communication failure (691), communication failure (692), communication failure (693), communication failure (694), communication failure (695)) may be restored. When a communication failure is restored, the operations of the network nodes (601, 602, 603, 604, 605) in 6b to 6f may perform the operations of the network nodes (601, 602, 603, 604, 605) exemplified in FIG. 6a.

[0226] According to one embodiment, network nodes (601, 602, 603, 604) may form a connection structure illustrated in FIGS. 6a through 6f. The cost for the connection structure illustrated in FIGS. 6a through 6f may be lower than the cost for implementing a redundant connection of each network node (601, 602, 603, 604) with a network node (605) (e.g., all network nodes (601, 602, 603, 604) implement the connection illustrated in FIGS. 5a through 5b). Additionally, the stability of the network of the connection structure illustrated in FIGS. 6a through 6f may be higher than the stability of the network of a structure in which network nodes (601, 602, 603, 604) are connected in series (e.g., all network nodes are connected in series).

[0227] FIG. 7a illustrates examples of operations in which a network node receives downlink traffic. The network node of FIG. 7a may include the network node (301) of FIG. 3.

[0228] Referring to FIG. 7a, in operation 701, a network node (301) (e.g., processor (300)) can determine whether the connection status of a first port (e.g., first port (321)) is normal or abnormal based on at least one of a first status message obtained from a first external network node (e.g., network node (301)) or a second status message obtained from a second external network node (e.g., network node (301)).

[0229] According to one embodiment, a network node (301) may include a first port (321) and a second port (e.g., a second port (322)). The first port (321) may be connected to a first external network node. The second port (322) may be connected to a second external network node. The second port (322) may be configured to forward, provide, or transmit traffic (e.g., downlink traffic) received from the first external network node through the first port (321) to the second external network node.

[0230] According to one embodiment, a network node (301) may obtain or receive a first status message from a first external network node through a first port (321). For example, the first status message may include the connection status of the first external network node. For example, the first status message may indicate the connection status of the ports of the first external network node. For example, the first external network node may be connected to another external network node. For example, the first external network node may obtain a status message of another external network node from another external network node. For example, the first status message may be generated at the first external network node based on the status message of the other external network node.

[0231] In response to receiving a first status message from a first external network node, the network node (301) may provide or transmit a response message for the first status message to the first external network node through the first port (321). For example, the response message may indicate that the first status message has been received. For example, the response message may indicate that the network node (301) received the first status message through the first port (321) among the first port (321) and the second port (322).

[0232] According to one embodiment, a network node (301) may obtain or receive a second status message from a second external network node through a second port (322). For example, the second status message may include the connection status of the second external network node. For example, the second status message may indicate the connection status of the ports of the second external network node. For example, the second external network node may be connected to another external network node. For example, the second external network node may obtain a status message of another external network node from the other external network node. For example, the second status message may be generated at the second external network node based on the status message of the other external network node.

[0233] According to one embodiment, the network node (301) may refrain from outputting the second status message obtained through the second port (322) through the first port (321). For example, the network node (301) may prevent a looping problem by refraining from outputting the second status message through the first port (321).

[0234] According to one embodiment, the network node (301) can determine or identify whether the connection status of the network node (301) is normal or abnormal based on at least one of a first status message or a second external message. For example, the connection status of the network node (301) may include the connection status of the first port (321).

[0235] A network node (301) may generate a third status message of the network node (301) based on the determined connection status of the network node (301). For example, the third status message may indicate the connection status of the network node (301). For example, the third status message may indicate the connection status of the ports of the network node (301) (e.g., first port (321), second port (322)). For example, the network node (301) may output the third status message through the second port (322) among the first port (321) and the second port (322). For example, the network node (301) may transmit or provide the third status message to a second external network node through the second port (322). For example, the network node (301) may refrain from transmitting the third status message to a first external network node through the first port (321). For example, the network node (301) can prevent looping problems by refraining from transmitting to the first external network node through the first port (321).

[0236] According to one embodiment, before determining whether the connection state of the first port (321) is normal or abnormal, the network node (301) may identify or determine whether the connection state of the second port (322) is a first state in which download traffic from the second external network node is transmitted, or a second state in which download traffic from the second external network node is not transmitted, based on a second state message obtained from the second external network node. For example, the first state may be referred to as a state in which the second port (322) of the network node (301) and the second port (e.g., the second port (322)) of the second external network node are connected. For example, the first state may include the connection state of the second port (632) of the network node (603) of FIG. 6a and / or the connection state of the second port (642) of the network node (604). For example, the first state may correspond to a daisy-chain connection structure of the network node (301). For example, the second state may be referred to as a state in which the second port (322) of the network node (301) and the first port (e.g., the first port (321)) of the second external network node are connected. For example, the first state may include the connection state of the second port (612) of the network node (601) in FIG. 6a and / or the connection state of the second port (622) of the network node (602). For example, the second state may correspond to a redundant connection structure of the network node (301).

[0237] According to one embodiment, a network node (301) can identify that the connection state of a second port (322) is the first state based on a second state message obtained from a second external network node. For example, the network node (301) can identify that the connection state of the second port (322) is the first state based on identifying that the second state message indicates that it is transmitted from a second port (e.g., second port (322)) of the second external network node and / or that the second state message indicates that the second port of the second external network node and the second port (322) of the network node (301) are connected. In one embodiment, the network node (301) can determine whether the connection state of the first port (321) is normal or abnormal based on identifying that the connection state of the second port (322) is the first state. However, the embodiments are not limited.

[0238] In operation 703, the network node (301) (e.g., processor (300)) may receive downlink traffic from the first external network node through the first port (321) based on the determination that the connection state of the first port (321) is normal. For example, the downlink traffic may include downlink traffic for the network node (301) and / or downlink traffic for the second external network node. For example, the downlink traffic for the network node (301) may include address information of the network node (301). For example, the downlink traffic for the second external network node may include address information of the second external network node.

[0239] According to one embodiment, a network node (301) can transmit, provide, or deliver traffic for a second external network node to the second external network node through a second port (322).

[0240] In operation 705, the network node (301) (e.g., processor (300)) may receive downlink traffic from a second external network node through a second port (322) upon determining that the connection state of the first port (321) is abnormal. For example, the downlink traffic may include downlink traffic for the network node (301) and / or downlink traffic for the first external network node. For example, the downlink traffic for the network node (301) may include address information of the network node (301). For example, the downlink traffic for the first external network node may include address information of the first external network node.

[0241] According to one embodiment, a network node (301) can transmit, provide, or deliver traffic for a first external network node to the first external network node through a first port (321).

[0242] FIG. 7b illustrates examples of operations in which a network node transmits uplink traffic. The network node of FIG. 7b may include the network node (301) of FIG. 3.

[0243] In operation 711, the network node (301) (e.g., processor (300)) can determine whether the connection status of the first port is normal or abnormal based on at least one of a first status message obtained from a first external network node or a second status message obtained from a second external network node.

[0244] According to one embodiment, a network node (301) may include a first port (321) and a second port (e.g., a second port (322)). The first port (321) may be connected to a first external network node. The second port (322) may be connected to a second external network node. The second port (322) may be configured to forward, provide, or transmit traffic (e.g., downlink traffic) received from the first external network node through the first port (321) to the second external network node.

[0245] According to one embodiment, a network node (301) may obtain or receive a first status message from a first external network node through a first port (321). For example, the first status message may include the connection status of the first external network node. For example, the first status message may indicate the connection status of the ports of the first external network node. In response to receiving the first status message from the first external network node, the network node (301) may provide or transmit a response message to the first status message to the first external network node through the first port (321).

[0246] According to one embodiment, a network node (301) may obtain or receive a second status message from a second external network node through a second port (322). For example, the second status message may include the connection status of the second external network node. For example, the second status message may indicate the connection status of the ports of the second external network node.

[0247] According to one embodiment, the network node (301) may determine or identify whether the connection state of the network node (301) is normal or abnormal based on at least one of a first status message or a second external message. For example, the connection state of the network node (301) may include the connection state of the first port (321). Operation 711 may correspond to or be substantially identical to operation 701 of FIG. 7a. For operation 711, the descriptions of operation 701 of FIG. 7a may be referenced.

[0248] In operation 713, the network node (301) (e.g., processor (300)) may transmit uplink traffic to the first external network node through the first port (321) upon determining that the connection state of the first port (321) is normal. For example, the uplink traffic may include uplink traffic for the network node (301) and / or uplink traffic for the second external network node. For example, the uplink traffic for the network node (301) may include address information of the network node (301). For example, the uplink traffic for the second external network node may include address information of the second external network node.

[0249] According to one embodiment, a network node (301) can transmit, provide, or deliver traffic for a second external network node to a first external network node through a first port (321).

[0250] In operation 715, the network node (301) (e.g., processor (300)) may transmit uplink traffic to a second external network node through the second port (322) upon determining that the connection state of the first port (321) is abnormal. For example, the uplink traffic may include uplink traffic for the network node (301) and / or uplink traffic for the first external network node. For example, the uplink traffic for the network node (301) may include address information of the network node (301). For example, the uplink traffic for the first external network node may include address information of the first external network node.

[0251] According to one embodiment, a network node (301) can transmit, provide, or deliver traffic for a first external network node to a second external network node through a second port (322).

[0252] According to one embodiment, in FIG. 7a and / or FIG. 7b, the connection state of a network node (301) can be determined or identified, and data communication with a core network (e.g., for communication services) can be performed according to the determined connection state. The network node (301) can determine or identify the connection state of the network node (301) without the intervention of an external control device. The network node (301) can perform data communication with a core network using a different port according to the determined connection state without the intervention of an external control device. Since the network node (301) performs data communication with a core network using a different port according to the determined connection state, network nodes (e.g., network node (301)) can form various connection structures. For example, network nodes can form connection structures illustrated in FIG. 6a through 6f. The cost for the connection structure exemplified in FIGS. 6a through 6f may be lower than the cost for implementing a redundant connection of each network node with a higher-layer network node (e.g., all network nodes implementing the connection exemplified in FIGS. 5a through 5b). Additionally, the stability of the network of the connection structure exemplified in FIGS. 6a through 6f may be higher than the stability of a network of a structure where network nodes are serially connected (e.g., all network nodes are serially connected). For example, while a network node (301) performs data communication with a core network using a first port (321), it may identify or determine that the connection state of the first port (321) is abnormal. The network node (301) may continue to perform data communication with the core network using a second port (322). While a network node (301) performs data communication with the core network using a second port (322), it may identify or determine that the connection state of the first port (321) changes from an abnormal state to a normal state.The network node (301) can perform data communication with the core network using the first port (321).

[0253] In an embodiment according to the present disclosure, the connection status of a network node (e.g., network node (301)) can be determined or identified, and data communication can be performed according to the determined connection status. The network node (301) can determine or identify the connection status of the network node (301) without the intervention of an external control device. The network node (301) can perform data communication with the core network in a different way (e.g., by using a different port) according to the determined connection status without the intervention of an external control device. Since the network node (301) performs data communication with the core network by using a different port according to the determined connection status, the network nodes (e.g., network node (301)) can form various connection structures. For example, the network nodes can form connection structures illustrated in FIGS. 6a through 6f. The cost for the connection structure exemplified in FIGS. 6a through 6f may be lower than the cost for implementing a redundant connection of each network node with a higher-layer network node (e.g., all network nodes implementing the connection exemplified in FIGS. 5a through 5b). Additionally, the stability of the network of the connection structure exemplified in FIGS. 6a through 6f may be higher than the stability of a network of a structure in which network nodes are serially connected (e.g., all network nodes are serially connected). For example, while a network node (301) performs data communication with a core network (e.g., for communication services) using a first port (321), it may identify or determine that the connection status of the first port (321) is abnormal. The network node (301) may continue to perform data communication with the core network using a second port (322). While the network node (301) performs data communication with the core network using the second port (322), it can identify or determine that the connection state of the first port (321) changes from an abnormal state to a normal state.The network node (301) can perform data communication with the core network using the first port (321).

[0254] The effects obtainable from the present disclosure are not limited to those mentioned above, and other unmentioned effects will be clearly understood by those skilled in the art to which the present disclosure belongs from the description below.

[0255] The technical problems to be solved in this disclosure are not limited to those mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art to which this disclosure belongs.

[0256] As described above, the network node may include a first port connected to a first external network node. The network node may include a second port connected to a second external network node and configured to transmit traffic received from the first external network through the first port to the second external network node. The network node may include a memory comprising one or more storage media for storing instructions. The network node may include at least one processor comprising processing circuitry. The instructions may cause the network node to determine whether the connection status of the first port is normal or abnormal based on at least one of a first status message obtained from the first external network node or a second status message obtained from the second external network node, when executed individually or collectively by the at least one processor. When the above instructions are executed individually or collectively by the at least one processor, they may cause the network node to receive downlink traffic containing address information of the network node from the first external network node through the first port, depending on the determination that the connection state of the first port is the normal state. When the above instructions are executed individually or collectively by the at least one processor, they may cause the network node to receive downlink traffic from the second external network node through the second port, depending on the determination that the connection state of the first port is the abnormal state.

[0257] According to one embodiment, when the instructions are executed individually or collectively by the at least one processor, the network node may be caused to receive other downlink traffic including address information of the second external network node from the first external network node through the first port, depending on the determination that the connection state of the first port is the normal state. When the instructions are executed individually or collectively by the at least one processor, the network node may be caused to transmit the other downlink traffic to the second external network node through the second port, depending on the determination that the connection state of the first port is the normal state.

[0258] According to one embodiment, when the instructions are executed individually or collectively by the at least one processor, they may cause the network node to receive other downlink traffic, including address information of the first external network node, from the second external network node through the second port, upon determining that the connection state of the first port is in the abnormal state. When the instructions are executed individually or collectively by the at least one processor, they may cause the network node to transmit the other downlink traffic to the first external network node through the first port, upon determining that the connection state of the first port is in the abnormal state.

[0259] According to one embodiment, when the instructions are executed individually or collectively by the at least one processor, the network node may be caused to transmit uplink traffic containing the address information of the network node to the first external network node through the first port, depending on the determination that the connection state of the first port is the normal state.

[0260] According to one embodiment, upon determining that the connection state of the first port is an abnormal state, uplink traffic including the address information of the network node is transmitted to the second external network node through the second port.

[0261] According to one embodiment, when the instructions are executed individually or collectively by the at least one processor, the network node may be caused to receive uplink traffic containing address information of the second external network node from the second external network node through the second port, upon determining that the connection state of the first port is in the normal state. When the instructions are executed individually or collectively by the at least one processor, the network node may be caused to transmit the uplink traffic to the first external network node through the first port, upon determining that the connection state of the first port is in the normal state.

[0262] According to one embodiment, when the instructions are executed individually or collectively by the at least one processor, the network node may be caused to receive uplink traffic containing address information of the first external network node from the first external network node through the first port, upon a determination that the connection state of the first port is in the abnormal state. When the instructions are executed individually or collectively by the at least one processor, the network node may be caused to transmit the uplink traffic to the second external network node through the second port, upon a determination that the connection state of the first port is in the abnormal state.

[0263] According to one embodiment, the network node may correspond to a distributed unit (DU). The first external network node may correspond to a switch connected to a centralized unit (CU). The second external network node may correspond to another DU.

[0264] According to one embodiment, when the instructions are executed individually or collectively by the at least one processor, the network node may be caused to refrain from transmitting the acquired second status message to the first external network node through the first port.

[0265] According to one embodiment, when the instructions are executed individually or collectively by the at least one processor, the network node may be caused to transmit the third status message to the second external network node by outputting the third status message indicating the connection status of the first port of the network node through the second port among the first port and the second port.

[0266] According to one embodiment, the instructions may cause the network node to identify, based on the second status message, that the connection state of the second port is the first state among a first state in which the download traffic from the second external network node is transmittable and a second state in which the download traffic from the second external network node is not transmittable, before determining whether the connection state of the first port is the normal state or the abnormal state when executed individually or collectively by the at least one processor.

[0267] A method performed at a network node having a first port connected to a first external network node and a second port connected to a second external network node as described above, configured to transmit traffic received from the first external network through the first port to the second external network node, may include an operation of determining whether the connection state of the first port is normal or abnormal based on at least one of a first status message obtained from the first external network node or a second status message obtained from the second external network node. The method may include an operation of receiving downlink traffic containing address information of the network node from the first external network node through the first port, in accordance with the determination that the connection state of the first port is normal. The method may include an operation of receiving downlink traffic from the second external network node through the second port, in accordance with the determination that the connection state of the first port is abnormal.

[0268] According to one embodiment, the method may include an operation of receiving other downlink traffic, including address information of the second external network node, from the first external network node through the first port, based on a determination that the connection state of the first port is the normal state. The method may include an operation of transmitting the other downlink traffic to the second external network node through the second port, based on a determination that the connection state of the first port is the normal state.

[0269] According to one embodiment, the method may include an operation of receiving other downlink traffic, including address information of the first external network node, from the second external network node through the second port, based on a determination that the connection state of the first port is in the abnormal state. The method may include an operation of transmitting the other downlink traffic to the first external network node through the first port based on a determination that the connection state of the first port is in the abnormal state.

[0270] According to one embodiment, the method may include the operation of transmitting uplink traffic containing the address information of the network node to the first external network node through the first port, based on the determination that the connection state of the first port is the normal state.

[0271] According to one embodiment, the method may include the operation of transmitting uplink traffic containing the address information of the network node to the second external network node through the second port, based on the determination that the connection state of the first port is the abnormal state.

[0272] According to one embodiment, the method may include an operation of receiving uplink traffic containing address information of the second external network node from the second external network node through the second port, based on a determination that the connection state of the first port is the normal state. The method may include an operation of transmitting the uplink traffic to the first external network node through the first port, based on a determination that the connection state of the first port is the normal state.

[0273] According to one embodiment, the method may include an operation of receiving uplink traffic containing address information of the first external network node from the first external network node through the first port, based on a determination that the connection state of the first port is the abnormal state. The method may include an operation of transmitting the uplink traffic to the second external network node through the second port, based on a determination that the connection state of the first port is the abnormal state.

[0274] According to one embodiment, the network node may correspond to a distributed unit (DU). The first external network node may correspond to a switch connected to a centralized unit (CU). The second external network node may correspond to another DU.

[0275] According to one embodiment, the method may include an operation of refraining from transmitting the acquired second status message to the first external network node through the first port.

[0276] According to one embodiment, the method may include the operation of transmitting a third status message to a second external network node by outputting the third status message, which indicates the connection status of the first port of the network node, through the second port among the first port and the second port.

[0277] According to one embodiment, the method may include, before determining whether the connection state of the first port is the normal state or the abnormal state, identifying, based on the second state message, that the connection state of the second port is the first state among a first state in which the download traffic from the second external network node is transmitted and a second state in which the download traffic from the second external network node is not transmitted.

[0278] In a computer-readable storage medium in which one or more programs are stored as described above, the one or more programs may include instructions that cause the network node to determine whether the connection state of the first port is normal or abnormal based on at least one of a first status message obtained from the first external network node or a second status message obtained from the second external network node, when executed by the network node having a second port connected to a first external network node and a second port configured to transmit traffic received from the first external network through the first port to the second external network node. The one or more programs may include instructions that cause the network node to receive downlink traffic containing address information of the network node from the first external network node through the first port, depending on the determination that the connection state of the first port is normal when executed by the network node. The above one or more programs may include instructions that cause the network node to receive the downlink traffic from the second external network node through the second port, upon determining that the connection state of the first port is abnormal when executed by the network node.

[0279] According to one embodiment, the one or more programs may include instructions that cause the network node to receive other downlink traffic, including address information of the second external network node, from the first external network node through the first port, upon determining that the connection state of the first port is the normal state when executed by the network node. The one or more programs may include instructions that cause the network node to transmit the other downlink traffic to the second external network node through the second port, upon determining that the connection state of the first port is the normal state when executed by the network node.

[0280] According to one embodiment, the one or more programs may include instructions that cause the network node to receive other downlink traffic, including address information of the first external network node, from the second external network node through the second port, upon determination that the connection state of the first port is abnormal when executed by the network node. The one or more programs may include instructions that cause the network node to transmit the other downlink traffic to the first external network node through the first port, upon determination that the connection state of the first port is abnormal when executed by the network node.

[0281] According to one embodiment, the one or more programs may include instructions that cause the network node to transmit uplink traffic containing the address information of the network node to the first external network node through the first port, upon determination that the connection state of the first port is the normal state when executed by the network node.

[0282] According to one embodiment, the one or more programs may include instructions that cause the network node to transmit uplink traffic containing the address information of the network node to the second external network node through the second port, upon determination that the connection state of the first port is abnormal when executed by the network node.

[0283] According to one embodiment, the one or more programs may include instructions that cause the network node to receive uplink traffic containing address information of the second external network node from the second external network node through the second port, upon determining that the connection state of the first port is the normal state when executed by the network node. The one or more programs may include instructions that cause the network node to transmit the uplink traffic to the first external network node through the first port, upon determining that the connection state of the first port is the normal state when executed by the network node.

[0284] According to one embodiment, the one or more programs may include instructions that cause the network node to receive uplink traffic containing address information of the first external network node from the first external network node through the first port, upon determining that the connection state of the first port is in the abnormal state when executed by the network node. The one or more programs may include instructions that cause the network node to transmit the uplink traffic to the second external network node through the second port, upon determining that the connection state of the first port is in the abnormal state when executed by the network node.

[0285] According to one embodiment, the network node may correspond to a distributed unit (DU). The first external network node may correspond to a switch connected to a centralized unit (CU). The second external network node may correspond to another DU.

[0286] According to one embodiment, the one or more programs may include instructions that cause the network node to refrain from transmitting the acquired second status message to the first external network node through the first port when executed by the network node.

[0287] According to one embodiment, the one or more programs may include instructions that cause the network node to transmit the third status message to the second external network node by outputting the third status message, which indicates the connection status of the first port of the network node, through the second port among the first port and the second port, when executed by the network node.

[0288] According to one embodiment, the one or more programs may include instructions that cause the network node to identify, based on the second status message, that the connection state of the second port is the first state among a first state in which the download traffic from the second external network node is transmitted and a second state in which the download traffic from the second external network node is not transmitted, before determining whether the connection state of the first port is the normal state or the abnormal state when executed by the network node.

[0289] The various embodiments of this document and the terms used therein are not intended to limit the technical features described in this document to specific embodiments, and should be understood to include various modifications, equivalents, or substitutions of said embodiments. In connection with the description of the drawings, similar reference numerals may be used for similar or related components. The singular form of a noun corresponding to an item may include one or more of said items unless the relevant context clearly indicates otherwise. In this document, phrases such as "A or B," "at least one of A and B," "at least one of A or B," "A, B or C," "at least one of A, B and C," and "at least one of A, B, or C" may each include any one of the items listed together in the corresponding phrase, or all possible combinations thereof. Terms such as "first," "second," or "first" or "second" may be used simply to distinguish said components from other said components and do not limit said components in any other aspect (e.g., importance or order). Where any (e.g., 1st) component is referred to as “coupled” or “connected” to another (e.g., 2nd) component, with or without the terms “functionally” or “communicationly,” it means that said any component may be connected to said other component directly (e.g., via a wire), wirelessly, or through a third component.

[0290] The term “module” as used in the various embodiments of this document may include a unit implemented in hardware, software, or firmware, and may be used interchangeably with terms such as logic, logic block, component, or circuit, for example. A module may be a component formed integrally, or a minimum unit of said component or a part thereof that performs one or more functions. For example, according to one embodiment, a module may be implemented in the form of an application-specific integrated circuit (ASIC).

[0291] Various embodiments of this document may be implemented as software comprising one or more instructions stored in a storage medium (e.g., memory (310)) readable by a machine (e.g., network node (301) of FIG. 3). For example, a processor (e.g., processor (300)) of the machine (e.g., network node (301)) may call at least one of the one or more instructions stored from the storage medium and execute it. This enables the machine to operate to perform at least one function according to the at least one called instruction. The one or more instructions may include code generated by a compiler or code that can be executed by an interpreter. The storage medium readable by the machine may be provided in the form of a non-transitory storage medium. Here, 'non-temporary' simply means that the storage medium is a tangible device and does not contain a signal (e.g., electromagnetic waves), and the term does not distinguish between cases where data is stored semi-permanently and cases where it is stored temporarily.

[0292] According to one embodiment, the method according to the various embodiments disclosed herein may be provided by being included in a computer program product. The computer program product may be traded between a seller and a buyer as a product. The computer program product may be distributed in the form of a device-readable storage medium (e.g., compact disc read-only memory (CD-ROM)), or distributed online (e.g., download or upload) through an application store (e.g., Play Store™) or directly between two user devices (e.g., smartphones). In the case of online distribution, at least a portion of the computer program product may be temporarily stored or temporarily created on a device-readable storage medium, such as the memory of a manufacturer's server, an application store's server, or a relay server.

[0293] According to various embodiments, each component (e.g., module or program) of the components described above may include a singular or multiple entities, and some of the multiple entities may be separated and placed in other components. According to various embodiments, one or more of the components or operations of the aforementioned components may be omitted, or one or more other components or operations may be added. Generally or additionally, multiple components (e.g., module or program) may be integrated into a single component. In this case, the integrated component may perform one or more functions of each of the multiple components in the same or similar manner as those performed by the corresponding component among the multiple components prior to integration. According to various embodiments, operations performed by the module, program, or other components may be executed sequentially, in parallel, iteratively, or heuristically, or one or more of the operations may be executed in a different order, omitted, or one or more other operations may be added.

Claims

1. Regarding network nodes, A first port connected to a first external network node; A second port connected to a second external network node and configured to transmit traffic received from the first external network through the first port to the second external network node; Memory comprising one or more storage media for storing instructions; and It includes at least one processor comprising a processing circuit, and When the above instructions are executed individually or collectively by the at least one processor, the network node: Based on at least one of a first status message obtained from the first external network node or a second status message obtained from the second external network node, determining whether the connection status of the first port is normal or abnormal, and Based on the determination that the connection state of the first port is the normal state, downlink traffic including address information of the network node is received from the first external network node through the first port, and Causing the downlink traffic to be received from the second external network node through the second port, based on the determination that the connection state of the first port is the abnormal state. Network node.

2. In Claim 1, When the above instructions are executed individually or collectively by the at least one processor, the network node: Based on the determination that the connection state of the first port is the normal state: Receiving other downlink traffic including address information of the second external network node from the first external network node through the first port, and Causing the above other downlink traffic to be transmitted to the second external network node through the second port, Network node.

3. In Claim 1, When the above instructions are executed individually or collectively by the at least one processor, the network node: Based on the determination that the connection state of the first port is the abnormal state: Receiving other downlink traffic including address information of the first external network node from the second external network node through the second port, and Causing the above other downlink traffic to be transmitted to the first external network node through the first port, Network node.

4. In Claim 1, When the above instructions are executed individually or collectively by the at least one processor, the network node: Causing uplink traffic including the address information of the network node to be transmitted to the first external network node through the first port, based on the determination that the connection state of the first port is the normal state. Network node.

5. In Claim 1, When the above instructions are executed individually or collectively by the at least one processor, the network node: Causing uplink traffic including the address information of the network node to be transmitted to the second external network node through the second port, based on the determination that the connection state of the first port is the abnormal state. Network node.

6. In Claim 1, When the above instructions are executed individually or collectively by the at least one processor, the network node: Based on the determination that the connection state of the first port is the normal state: Uplink traffic including address information of the second external network node is received from the second external network node through the second port, and Causing the above uplink traffic to be transmitted to the first external network node through the first port, Network node.

7. In Claim 1, When the above instructions are executed individually or collectively by the at least one processor, the network node: Based on the determination that the connection state of the first port is the abnormal state: Uplink traffic including address information of the first external network node is received from the first external network node through the first port, and Causing the above uplink traffic to be transmitted to the second external network node through the second port, Network node.

8. In Claim 1, The above network node corresponds to a DU (distributed unit), and The first external network node above corresponds to a switch connected to a CU (centralized unit), and The above-mentioned second external network node corresponds to another DU, Network node.

9. In Claim 1, When the above instructions are executed individually or collectively by the at least one processor, the network node: Causing to refrain from transmitting the above-mentioned second status message to the first external network node through the first port, Network node.

10. In Claim 1, When the above instructions are executed individually or collectively by the at least one processor, the network node: By outputting a third status message indicating the connection status of the first port of the network node through the second port among the first port and the second port, thereby causing the third status message to be transmitted to the second external network node. Network node.

11. In Claim 1, When the above instructions are executed individually or collectively by the at least one processor, the network node: Before determining whether the connection state of the first port is the normal state or the abnormal state, based on the second state message, causing the connection state of the second port to identify the first state among the first state in which the download traffic from the second external network node is transmittable and the second state in which the download traffic from the second external network node is not transmittable, Network node.

12. A method performed in a network node having a first port connected to a first external network node and a second port connected to a second external network node, configured to transmit traffic received from the first external network through the first port to the second external network node, wherein An operation to determine whether the connection status of the first port is normal or abnormal based on at least one of a first status message obtained from the first external network node or a second status message obtained from the second external network node. An operation of receiving downlink traffic containing address information of the network node from the first external network node through the first port, based on a determination that the connection state of the first port is the normal state, and A method comprising receiving downlink traffic from the second external network node through the second port, based on a determination that the connection state of the first port is the abnormal state. method.

13. In Claim 12, Based on the determination that the connection state of the first port is the normal state: The operation of receiving other downlink traffic including address information of the second external network node from the first external network node through the first port, and The operation further includes transmitting the above other downlink traffic to the second external network node through the second port. method.

14. In Claim 12, Based on the determination that the connection state of the first port is the abnormal state: The operation of receiving other downlink traffic including address information of the first external network node from the second external network node through the second port, and The operation further comprising transmitting the above other downlink traffic to the first external network node through the first port, method.

15. In Claim 12, The method further includes the operation of transmitting uplink traffic containing the address information of the network node to the first external network node through the first port, in accordance with the determination that the connection state of the first port is the normal state. method.

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