Dual-homing protection method and device and computer readable medium

Abstract

The embodiment of the invention relates to a dual-homing protection method, a dual-homing protection device and a computer readable medium. In an example method, at a first transmission node, a protection state of a first port of the first transmission node is determined based on at least one of at least one local request or a control message from a second transmission node. The first port and a second port of the second transmission node are coupled to the client device, the port function of the first port is one of a working port or a protection port, and the port function of the second port is the other of the working port or the protection port. Then, in the method, a usage state of the first port with respect to the client device is determined based on the protected state of the first port and the port functionality, where the usage state includes active or standby. In this way, a fast dual-homing port protection mechanism is achieved, the client device does not need to support any protection protocol, and the protected client device is not required to have two ports.

Description

Technical Field

[0001] Embodiments of the present disclosure generally relate to the field of communications, and more particularly to a dual-homing protection method, apparatus, and computer-readable medium. Background Art

[0002] With the development of optical communication technology, fronthaul networks based on optical network architecture are becoming increasingly popular. Fronthaul networks enable service data transmission between customer devices, such as transmission between radio units (RUs) and distributed units (DUs). In order to improve the reliability of data transmission, some service providers form a primary-backup protection switching mechanism (also known as dual-homing protection) through two communication links between customer devices.

[0003] However, some traditional customer equipment does not support the relevant protection switching protocol, and the conventional protection switching mechanism takes too long to switch. Therefore, further research and development of a more widely used and faster response protection switching mechanism is needed. Summary of the invention

[0004] In general, example embodiments of the present disclosure relate to a protection mechanism for fast dual-homing ports.

[0005] In a first aspect of the present disclosure, a device is provided, comprising: at least one processor; and at least one memory, wherein the at least one memory stores instructions, which, when executed by the at least one processor, cause the device to at least: determine, at a first transmission node, a protection state of a first port of the first transmission node based on at least one local request generated by the first transmission node or at least one control message from a second transmission node, wherein the first port and a second port of the second transmission node are coupled to a customer device, a port function of the first port is one of a working port or a protection port, and a port function of the second port is the other of the working port or the protection port; and determine a usage state of the first port with respect to the customer device based on the protection state and the port function of the first port, wherein the usage state includes activation or standby.

[0006] In a second aspect of the present disclosure, a method is provided, comprising: at a first transmission node, based on at least one of at least one local request generated by the first transmission node or at least one control message from a second transmission node, determining a protection state of a first port of the first transmission node, wherein the first port and a second port of the second transmission node are coupled to a customer device, a port function of the first port is one of a working port or a protection port, and a port function of the second port is the other of the working port or the protection port; and based on the protection state and the port function of the first port, determining a usage state of the first port with respect to the customer device, wherein the usage state includes activation or standby.

[0007] In a third aspect of the present disclosure, a device is provided, comprising: a component for determining, at a first transmission node, a protection status of a first port of a first transmission node based on at least one of at least one local request generated by the first transmission node or at least one control message from a second transmission node, wherein the first port and the second port of the second transmission node are coupled to a customer device, a port function of the first port is one of a working port or a protection port, and a port function of the second port is the other of the working port or the protection port; and a component for determining a usage status of the first port with respect to the customer device based on the protection status and the port function of the first port, wherein the usage status includes activation or standby.

[0008] In a fourth aspect of the present disclosure, a computer-readable medium is provided, on which instructions are stored, which, when executed by a device, cause the device to at least perform: at a first transmission node, based on at least one local request generated by the first transmission node or at least one control message from a second transmission node, determine a protection state of a first port of the first transmission node, wherein the first port and a second port of the second transmission node are coupled to a customer device, a port function of the first port is one of a working port and a protection port, and a port function of the second port is the other of the working port and the protection port; and based on the protection state and the port function of the first port, determine a usage state of the first port with respect to the customer device, wherein the usage state includes activation or standby.

[0009] In a fifth aspect of the present disclosure, a computer program comprising instructions is provided, which, when executed by a device, causes the device to at least: determine, at a first transmission node, a protection state of a first port of the first transmission node based on at least one of at least one local request generated by the first transmission node or at least one control message from a second transmission node, wherein the first port and a second port of the second transmission node are coupled to a customer device, a port function of the first port is one of a working port or a protection port, and a port function of the second port is the other of the working port or the protection port; and determine a usage state of the first port with respect to the customer device based on the protection state and the port function of the first port, wherein the usage state includes activation or standby.

[0010] In a sixth aspect of the present disclosure, a device is provided, comprising: a protection status determination circuit, configured to determine, at the first transmission node, a protection status of a first port of a first transmission node based on at least one local request generated by the first transmission node or at least one control message from a second transmission node, wherein the first port and the second port of the second transmission node are coupled to a customer device, a port function of the first port is one of a working port or a protection port, and a port function of the second port is the other of the working port or the protection port; and a usage status determination circuit, configured to determine a usage status of the first port with respect to the customer device based on the protection status and the port function of the first port, wherein the usage status includes activation or standby.

[0011] It should be understood that the contents described in the summary of the invention are not intended to limit the key or important features of the embodiments of the present disclosure, nor are they intended to limit the scope of the present disclosure. Other features of the present disclosure will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 An example communication system is shown in which embodiments of the present disclosure may be implemented.

[0013] Figure 2 An interactive schematic diagram of a communication method according to some embodiments of the present disclosure is shown.

[0014] Figure 3 A schematic block diagram of a dual homing port protection (DHPP) system according to some embodiments of the present disclosure is shown.

[0015] Figure 4 An example implementation of a DHPP module according to some embodiments of the present disclosure is shown.

[0016] FIG. 5A to FIG. 5C An example implementation of control messages for DHPP according to some embodiments of the present disclosure is shown.

[0017] Figure 6 A schematic diagram of a DHPP system in normal conditions is shown, according to some embodiments of the present disclosure.

[0018] Figure 7 A schematic diagram of a DHPP system in which a service data link failure occurs according to some embodiments of the present disclosure is shown.

[0019] Figure 8 A schematic diagram of a DHPP system in which an active node failure occurs according to some embodiments of the present disclosure is shown.

[0020] Fig. 9 A schematic diagram of a DHPP system in which a backup node failure occurs according to some embodiments of the present disclosure is shown.

[0021] Fig.10 A schematic diagram of a DHPP system in which a DHPP control link failure occurs according to some embodiments of the present disclosure is shown.

[0022] Fig.11 A schematic diagram of a DHPP system in which a pairing link failure and a DHPP control link failure occur according to some embodiments of the present disclosure is shown.

[0023] Fig.12 A schematic diagram of a DHPP system for a dual-port client device according to some embodiments of the present disclosure is shown.

[0024] Fig.13 A schematic flow chart of a communication method according to some embodiments of the present disclosure is shown.

[0025] Fig.14 A simplified block diagram of an electronic device suitable for implementing embodiments of the present disclosure is shown.

[0026] Fig.15 A schematic diagram of a computer-readable medium suitable for implementing an embodiment of the present disclosure is shown.

[0027] Throughout the drawings, the same or similar reference numerals refer to the same or similar elements. DETAILED DESCRIPTION

[0028] The principles and spirit of the present disclosure will be described below with reference to several exemplary embodiments shown in the accompanying drawings. It should be understood that these specific embodiments are described only to enable those skilled in the art to better understand and implement the present disclosure, and are not intended to limit the scope of the present disclosure in any way.

[0029] As used herein, the term "including" and similar terms should be understood as open inclusion, i.e., "including but not limited to". The term "based on" should be understood as "based at least in part on". The term "one embodiment" or "the embodiment" should be understood as "at least one embodiment". The terms "first", "second", etc. may refer to different or the same objects. Other explicit and implicit definitions may also be included below.

[0030] As used herein, the term "determine" covers a variety of actions. For example, "determine" may include operation, calculation, processing, export, investigation, search (e.g., search in a table, a database or another data structure), ascertain, etc. In addition, "determine" may include receiving (e.g., receiving information), accessing (e.g., accessing data in a memory), etc. In addition, "determine" may include parsing, selecting, selecting, establishing, etc. As used herein, "at least one of the following: " and "at least one of " and similar expressions, wherein a list of two or more elements is connected by "and" or "or", means at least any one of these elements, or at least any two or more of these elements, or at least all of them.

[0031] As used herein, the term "circuitry" refers to one or more of: (a) a hardware circuit implementation only (such as an implementation of analog and / or digital circuits only); and (b) a combination of hardware circuitry and software, such as (where applicable): (i) a combination of analog and / or digital hardware circuitry and software / firmware, and (ii) any portion of a hardware processor with software (including a digital signal processor, software, and memory that work together to enable an apparatus such as a switch or other computing device to perform various functions); and (c) a hardware circuit and / or processor, such as a microprocessor or a portion of a microprocessor, that requires software (e.g., firmware) for operation, but may be without software when software is not required for operation.

[0032] The definition of circuitry applies to all uses of this term in this application, including in any claims. As another example, the term "circuitry" as used herein also covers an implementation of only a hardware circuit or processor (or multiple processors), or a portion of a hardware circuit or processor, or accompanying software or firmware. For example, the term "circuitry" also covers a baseband integrated circuit or a processor integrated circuit or a similar integrated circuit in a switch or other computing device, if applicable to the particular claim notation.

[0033] For dual-homing topology, the popular protection mechanisms in packet transmission networks are multi-chassis link aggregation (MC-LAG) and Ethernet ring protection (ERP). The limitations of these two protection mechanisms are that both MC-LAG and ERP require the customer equipment to support the same protection protocol and control the switching of the other end of the link so that the message transmission system can coordinate with the customer equipment to perform protection switching, and both MC-LAG and ERP require the customer equipment side to have two ports, one port is the active port and the other port is the standby port.

[0034] In addition, more and more service providers are transforming their networks into cloud-based solutions. For example, open radio access network (Open RAN) and virtual radio access network (vRAN) are two of the hottest topics. Open radio access network uses industry standardized interfaces between baseband unit (BBU) and radio unit (RU), such as O-RAN interface, enhanced common public radio interface (eCPRI), common public radio interface (CPRI), etc. to decompose mobile base stations. vRAN replaces BBU with software running on general-purpose servers, which provides operators with greater flexibility and agility in their networks and the possibility of selecting a wider range of software from different suppliers. vRAN includes equipment such as virtual distributed unit (vDU) and virtual central unit (vCU) required by 3GPP and Open RAN standard organizations.

[0035] When network functions are implemented through software on general-purpose servers, processing efficiency depends on the performance of processors such as the central processing unit (CPU), graphics processing unit (GPU), and data processing unit (DPU). Unlike hardware-based application-specific integrated circuits (ASICs) or field-programmable gate arrays (FPGAs) that support processing at line rates, the computing power of processors is greatly affected by load, so in order to reduce load, some network functions are not supported.

[0036] Some service providers are planning to build a next-generation fronthaul transmission network to carry business data between RU and vDU / vCU, which deploys two fronthaul transmission nodes to provide redundancy when one node fails. In order to ensure performance, it may be necessary to provide a fast automatic protection mechanism of 50ms or less in the event of node failure and link failure. However, in order to reduce costs, RU usually has only one uplink interface to vDU, and RU / vDU / vCU generally does not support any traditional fast protection protocols, such as LAG, MC-LAG, ERP, ELP (Ethernet Linear Protection). To address this problem, the conventional solution is: on the RU side, for RUs that do not support automatic protection, they can only be switched manually by the operator; on the vDU / vCU side, the MC-LAG mechanism is supported by disabling the Link Aggregation Control Protocol (LACP) protocol, but the performance is poor and the time required for protection switching is in seconds.

[0037] In addition to cloud networks, some devices in traditional non-cloud networks do not support any Layer 2 protection mechanisms such as LAG / MC-LAG / ERP / ELP. If a service interruption time of less than 50ms is required, for example, a fast protection mechanism is also required.

[0038] In view of this, the embodiments of the present disclosure provide a fast dual-home port protection mechanism, which does not require the customer device to support any protection protocol, nor does it require the customer device to have two ports. The basic concept of the embodiments of the present disclosure is that the fast protection mechanism works between two local packet transmission nodes, exchanges control messages of protection status between the two transmission nodes, and controls the two working / protection links connected to the customer device to ensure that only one link is "activated" at a time for forwarding service data between customer devices. The mechanism can control switching based on defects detected locally without exchanging control messages with customer devices. In some implementations, for customer devices with only a single port, a Y-type cable (including a Y-type optical cable and a Y-type electrical cable) can be used to form two links (split from the unique port of the customer device into two replicated signals, which are replicated to two peer transmission nodes respectively), and the laser that triggers the shutdown of the port connected to the customer device can be configured to avoid the signal overlap problem of the Y-type cable.

[0039] Figure 1 An example communication system 100 in which an embodiment of the present disclosure can be implemented is shown. The communication system 100 may be an optical transmission system or a packet transmission system, and is implemented in a fronthaul network, for example, at a base station of 4G, 5G or other standards. As shown in the figure, the communication system 100 includes a first transmission node 110, a second transmission node 120, a customer device 130, and a customer device 140. The customer device 130 may be a radio unit (RU) or a router, etc., and the customer device 140 may be a distributed unit (DU), or a virtual distributed unit (vDU) implemented in software on a general-purpose processor. The first transmission node 110 and the second transmission node 120 may be switch devices, such as Ethernet service switches. The first transmission node 110 and the second transmission node 120 may include physical or logical ports (112, 122, 114, 124, 116, 126) for communication with the customer device 130, the customer device 140 or communication between each other. The port can be used for any EVC service (e.g., E-line / E-LANE / E-Tree service).

[0040] The client device 130 and the client device 140 can perform bidirectional data transmission via one or more ports in the first transmission node 110 and the second transmission node 120. For example, the service data transmission from the client device 130 to the client device 140 can be referred to as uplink transmission, and the service data transmission from the client device 140 to the client device 130 can be referred to as downlink transmission. It should be understood that the communication system 100 may include Figure 1 The different numbers of client devices 130 and 140 shown provide data forwarding services between the multiple client devices 130 and the multiple client devices 140 at the same time.

[0041] As mentioned above, the communication system 100 generally needs to support a protection mechanism for recovering user service data between the client devices 130 and 140 in response to a link failure or a failure of the transmission nodes 110 and 120. Figure 1 As shown, the connected customer device 130 can access the two redundant transmission nodes 110 and 120 in a dual-homing manner. The customer device 130 can be connected to the port 112 of the first transmission node 110, and connected to the port 122 of the second transmission node 120, respectively forming links that can be used for business data transmission. The first transmission node 110 also includes a port 116 connected to the upstream customer device 140. Similarly, the second transmission node 120 includes a port 126 connected to the above customer device 140. The first transmission node 110 and the second transmission node 120 can also be connected to each other through the pairing ports 114 and 124 to form a pairing link, which can carry business data and / or control messages for protection. It should be understood that Figure 1 The number of ports shown is for illustration only, and the embodiments of the present disclosure are not limited in this respect. For example, the first transmission node 110 and the second transmission node 120 may each have multiple ports for the downstream client device 130 and multiple ports for the upstream client device 140, and each transmission node may have multiple paired ports to form multiple paired links.

[0042] In order to achieve data protection when a failure occurs, the port 112 of the first transmission node 110 and the port 122 of the second transmission node 120 can form a port group, and the port 112 of the first transmission node 110 can be set as a working port (for example, having higher performance and being used most of the time), and the port 122 of the second transmission node 120 is set as a protection port. It should be understood that the opposite setting is also possible. In some implementations, there can be multiple port groups on a node, and some of the ports of the first transmission node 110 are working ports and some are protection ports, and the second transmission node 120 can also be the same. In normal operation, only one transmission port in a port group is activated at the same time, and the other transmission port is in a standby state, for example, the first port 112 is activated and the second port 122 is in standby state. At this time, the client device 130 can send and receive service data with the client device 140 via the port 112 and the port 116 of the first transmission node 110, and the corresponding service access point is not blocked, while the port 122 of the second transmission node 120 is in standby mode, and the client device 130 does not send and receive service data with the client device 140 through the port 122. When the communication between the client device 130 and the client device 140 fails (for example, a transmission node failure or a link failure), the standby transmission node 120 can take over the service data. The node failure can be, for example, a hardware failure at the node level, an intentional or unintentional restart and shutdown, etc. The link failure may occur in the link carrying service data connected to the access device 130, the paired link carrying service data between the two transmission nodes, or the paired link carrying control messages for protection between the two transmission nodes, etc. At this time, the client device 130 can switch to continue communicating with the client device 140 via the ports 122 and 126 of the second transmission device ( Figure 1 (not shown) It should be noted that the protection switching mechanism according to the embodiment of the present disclosure can be implemented not only in the downstream customer equipment 130, but also in the upstream customer equipment 140, and the embodiment of the present disclosure is not limited in this respect.

[0043] According to the embodiments of the present disclosure, the desired protection switching can achieve at least some of the following aspects: in the event of an active node failure, the business data of all ports of the active node should be switched to the standby node; in the event of a standby node failure, the business data of all ports of the active node should not be affected, and no traffic loss will occur; in the event of a port failure of the active node, the business data of the port can be switched to the corresponding port of the standby node; in the event of a port failure of the standby node, the traffic of the corresponding port of the active node should not be affected, and no business data loss will occur; in the event of a paired link failure, the business data can still be recovered and forwarded.

[0044] To this end, the embodiment of the present disclosure proposes an improved technical solution, which can collaboratively implement port-based fast dual-homing protection based on local requests and control messages between transmission nodes. Figures 2 to 15 Embodiments of the present disclosure are described in detail.

[0045] Figure 2 FIG. 2 shows an interactive schematic diagram of a communication method 200 according to some embodiments of the present disclosure. The communication method 200 may be performed as follows: Figure 1 The dual homing protection function is implemented by the first transmission node 110 and the second transmission node 120 shown. In some implementations, the dual homing protection function implemented on the first transmission node 110 and the second transmission node 120 can be equal, that is, the action of the first transmission node 110 can be implemented by the second transmission node 120, and the action of the second transmission node 120 can be implemented by the first transmission node 110. Alternatively, the dual homing protection function can be implemented on one of the first transmission node 110 and the second transmission node 120, and the other node is only responsible for reporting the failure of the local port and executing the usage status determined by the opposite end. For the convenience of explanation, refer to Figure 1 The interaction flow 200 is described.

[0046] At 201, the first transmission node 110 determines the protection state of the first port 112 of the first transmission node 110 based on at least one of at least one local request generated by the first transmission node 110 or at least one control message from the second transmission node 120. The local request may be a request triggered at the first transmission node, for example, a link or node failure is detected, performance degradation, a protection switch manually triggered by a user, a protection switch initiated by the node itself, etc. Each local request may indicate one of a set of protection states. In some implementations, the first transmission node 110 may obtain the local request periodically, or in response to an event, for example, when any local request changes, obtain the triggering state of all local requests of the first transmission node 110.

[0047] The first transmission node 110 may also receive a control message from the second transmission node 120, for example, via a paired link between paired ports 114 and 124. The paired link carrying the control message may be a separate link or a shared link carrying service data between the transmission nodes 110 and 120. Control from the second transmission node 120. The control message may include a remote request indicating a protection state of the second port 122 of the second transmission node. In some implementations, the first transmission node 110 may periodically receive a control message from the second transmission node 120, or receive a corresponding control message when an event occurs at the second transmission node 120.

[0048] In some embodiments, each protection state in the above set of protection states may have an associated priority. The protection state with the highest priority indicated in the local request and the remote request may be determined as the protection state of the first port. In other words, the request with the highest priority may be found, and the protection state of the first port 112 may be determined based on the request with the highest priority.

[0049] At 202, at the first transmission node 110, based on the protection state and port function of the first port 112, the use state of the first port 112 with respect to the client device 130 is determined. The first port 112 of the first transmission node 110 and the second port 122 of the second transmission node 120 can be coupled to the client device 130 and have paired port functions to achieve dual homing protection. In this article, the port function may also be referred to as the port role, and the two may be used interchangeably. For example, the port function of the first port 112 may be a working port, and the port function of the second port 122 may be a protection port (it should be understood that the opposite setting also applies). In some implementations, the port function or role may be set based on the performance and load conditions of the transmission node. In normal operation, the first port is activated and the second port 122 is in standby, that is, the client device 130 sends and receives service data via the first port 112, and the service data at the second port 122 (if any) is discarded. After protection switching occurs (for example, the first transmission node 110 or the first port 112 fails), the client device 130 may be switched to send and receive service data via the second port 122 to implement service data protection.

[0050] In some embodiments, the protection state may indicate a usage state associated with a port function. The usage state of a port function may be represented by the following configurations: the working port is activated and the protection port is standby, the working port is standby and the protection port is activated, both the working port and the protection port are activated, etc. Therefore, it may be determined whether the first port needs to be activated or standby according to the determined protection state of the first port and the port function of the first port.

[0051] In some embodiments, if the usage state of the first port 112 is determined to be active, packets from or to the client device 130 are forwarded at the first port 112, and media access control (MAC) address learning can be enabled in the receive direction. If the usage state of the first port 112 is determined to be standby, packets at the first port 112 are discarded, and MAC address learning in the receive direction is stopped. In some embodiments, if the usage state changes, the MAC addresses learned on the first port and the paired port 114 connected to the second transmission node 120 can be flushed. Additionally or alternatively, the MAC addresses in the entire filtering database (FDB) of the transmission node 110 can be flushed.

[0052] In some embodiments, one port of the client device is coupled to the first port 112 and the second port 122 via an optical splitter / combiner (e.g., a Y-cable). If the use status of the first port 112 is determined to be standby, the transmit laser at the first port 112 may be turned off. If the use status of the first port 112 is determined to be active, the transmit laser at the first port 112 may be turned on.

[0053] At 203, a control message 205 is sent from the first transport node 110 to the second transport node 120. Accordingly, the second transport node 120 receives the control message 205 from the first transport node 110. The control message 205 may indicate the protection state, the usage state, and other information of the first port 110. The control message 205 may be sent periodically, or may be sent when a failure occurs in the first transport node 110, or when the protection state or the usage state of the first port 112 changes.

[0054] At 206, at the second transport node 120, based on at least one of at least one local request generated by the second transport node 120 or at least one control message from the first transport node 110, a protection state of the second port 122 of the second transport node 120 is determined. At 207, based on the protection state of the second port 122 and the port function, a usage state of the second port 122 with respect to the client device 130 is determined. At 208, a control message 215 is sent from the second transport node 120 to the first transport node 110. Accordingly, the first transport node 110 receives the control message 215 from the second transport node 120. In some implementations, the dual-homing protection functions implemented on the first transport node 110 and the second transport node 120 may be peer-to-peer, and the actions at the second transport node 120 are similar to actions 201 to 203 of the first transport node 110, which are not repeated here. In some implementations, the dual homing protection function can be implemented only at the first transmission node 110, and the second transmission node 120 does not determine the protection state or usage state of the local port, but only reports the fault of the second port 122, and receives and applies the usage state determined by the first transmission node 110. In other words, actions 206 and 207 can be omitted, and the control message 215 is mainly used to indicate the fault information of the second port 122. Thus, the first transmission node 110 and the second transmission node 120 can negotiate the usage state of the paired first port and the second port by exchanging control messages and combining local requests, thereby realizing fast dual homing protection for client devices without requiring the client devices to support additional protection switching protocols.

[0055] Figure 3 A schematic block diagram of a dual homing port protection (DHPP) system according to some embodiments of the present disclosure is shown. The DHPP mechanism can be used to implement Figure 2An exemplary implementation of the interactive process 200 is shown. In some implementations, the client device 130 has a single port, and the optical splitter / combiner 150 can be used to expand the single port into two ports, one port coupled to the first port 112, and the other port coupled to the second port 122. If the client device 130 itself has two ports, it can be directly coupled to the first port 112 and the second port 122.

[0056] The first transmission node 110 and the second transmission node 120 may operate at layer 2, which may also be referred to as switch nodes. Figure 3 As shown, when the client device 130 is connected to two redundant transmission nodes 110 and 120 in a dual-homing manner, paired DHPP processes or modules 115 and 125 (the two DHPP modules may also be collectively referred to as a DHPP group) may be respectively run in the two transmission nodes to implement Figure 2 The interactive process 200 is shown. Specifically, the DHPP group is distributed in two redundant transmission nodes 110 and 120 , wherein the first transmission node 110 includes a DHPP module 115 , and the second transmission node 120 includes a DHPP module 125 .

[0057] The DHPP modules 115 and 125 may have the same functions. The paired DHPP modules 115 and 125 may operate in coordination to control a pair of ports 112 and 122, so that the use state of one of the ports 112 and 122 is activated and the use state of the other port is standby, thereby protecting the service data transmission between the transmission node and the client device in the event of a failure in the communication system, and having a smaller service interruption time. For coordination, the paired DHPP modules 115 and 125 may exchange control messages to synchronize information about protection status, switching commands, activation / standby status, and flushing of the filtering database (FDB). It should be noted that the first transmission node 110 and the second transmission node 120 may be included in the same device or different devices, and the paired first port 112 and the second port 122 may also be controlled by a single DHPP module.

[0058] Figure 4 An example implementation of a DHPP module according to some embodiments of the present disclosure is shown. The DHPP module may have a protection state conversion function. With this function, the DHPP module may determine the protection state of a port and its usage state based on a local request and a control message from another transmission node.

[0059] In some embodiments, the protection state of the port may be one of a set of protection states. Each protection state may have an associated priority. In some embodiments, the set of protection states may include at least one of the following: Lockout on working (LO-W), Lockout on protection (LO-P); Mate Fail (MF), Forced switch on working (FS-W), Forced switch on protection (FS-P), Signal fail on working (SF-W), Signal fail on protection (SF-P), Signal degrade on working (SD-W), Signal degrade on protection (SD-P), Manual swtich on working (MS-W), Manual swtich on protection (MS-P), No request on working (NR-W), or No request on protection (NR-P). Here, the paired link failure refers to the paired port failure carrying the service data or the control link failure about DHPP. The paired port carrying the service data and the port carrying the DHPP control link may be the same or different. It should be understood that, depending on the implementation, more protection states may be included, such as Wait to restore (WTR), Exercise (EXER), Reverse request (RR), Do not revert (DNR), etc.

[0060] The above protection states may have the following priorities from high to low: locked (LO-W / LO-P) > paired link failure (MF) > forced switching (FS-W / FS-P) > link failure (SF-W / SF-P) > link degradation (SD-W / SD-F) > manual switching (MS-W / MS-P) > work no request (NR-W) > protection no request (NR-P). Alternatively, the above protection states may also have the following priorities from high to low: locked (LO-W / LO-P) > forced switching (FS-W / FS-P) > paired link failure (MF) > link failure (SF-W / SF-P) > link degradation (SD-W / SD-F) > manual switching (MS-W / MS-P) > work no request (NR-W) > protection no request (NR-P).

[0061] The DHPP module can realize the transition of protection status based on the above priorities. Figure 4 As shown, the DHHP module includes a local priority logic 402, a global priority logic 404, a validity check logic 406, a mismatch detection logic 408, etc. The local priority logic 402 is used to receive a local request and output the highest priority local request. The validity check logic 406 is used to receive a control message of a remote transmission node, and output the remote request after checking. Assuming that the DHPP module is the DHPP module 115, it receives a control message of the second transmission node 120, and the remote request indicates the protection state of the second port 122. The global priority logic 404 is used to determine the highest priority global request from the remote request and the highest priority local request. Then, the DHPP module can determine the protection state of the port based on the highest priority global request and the previous protection state of the port, and determine the use state of the local port based on the determined protection state.

[0062] In some embodiments, if commands / conditions of the same priority are executed simultaneously on two transmission nodes, that is, the local request and the remote request have the same priority, the command / condition with the activation of the working port takes precedence over the command / condition with the activation of the protection port. In other words, if the local port of the DHPP module is a working port, the DHPP module determines the use state of the port as activation, and if the local port is a standby port, the DHPP module determines the use state of the port as standby.

[0063] In some embodiments, the protection state of the port can be determined based on one or more state transition tables. The state transition table can be set based on the mode of protection switching, such as return switching and non-return switching. Return switching refers to the mode of switching the service data back to the working node or the working port after the fault of the working node or the working port is eliminated, and non-return switching refers to the mode of not switching back to the working node or the working port after the fault of the working node or the working port is eliminated, but continuing to transmit service data on the protection node or the protection port. In some embodiments, the state transition table can also set different state transition tables respectively for whether the highest priority global request is a local request or a remote request. It should be understood that in the state transition table, if the priority of the previous protection state is higher than the priority of the protection state indicated by the highest priority global request, the protection state may not be changed.

[0064] In some embodiments, in some implementations, the DHPP module may also use mismatch detection logic 408 to check whether the usage status of the remote port matches the usage status of the locally determined port. If not, an error message may be generated indicating that the protection switching is not completed. FIG. 5A to FIG. 5C An example implementation of control messages for DHPP according to some embodiments of the present disclosure is shown. Figure 5A An exemplary control message based on the protocol datagram (PDU) format is shown. 4 bytes are used to carry request information from or to be sent to the remote end. In some embodiments, other fields can be defined as follows: Version: 0x00, Opcode: 0d39 (= 0x27), Flags: 0x00, END TLV: 0x00. In the MEL field, the maintenance entity group (MEG) level of the PDU is inserted.

[0065] Figure 5B Shows Figure 5A The request information includes request / status, protection type, request signal (r), bridge information (b), bridge type (T), setting of paired link failure (P), and reserved bits.

[0066] Figure 5CThe fields in Figure B and their meanings are shown. It should be noted that in the case of a pairing link failure (MF), a single bit P is used to indicate two options when a pairing link failure occurs. Option 1 (for example, P is 0), maintains the current activation (unblocked) state and the current standby (blocked) state of the ports in the DHPP group, and option 2 (for example, P is 1), both ports in the DHPP group are in the activated (unblocked) state. Option 1 is mainly used in the case where the two ports of the DHPP group are connected to the customer equipment CE through a splitter / combiner (for example, a Y-type cable). Option 2 is mainly used in the case where the two ports of the DHPP group are connected to the two ports of the customer equipment CE. In some embodiments, if the highest priority request indicates that the pairing link fails (MF), the usage status of the ports of the DHHP group can be determined based on the P bit in the control message. If it is option 0, the usage status of the two ports can be kept unchanged, and if it is option 1, it is determined that the usage status of the two ports is activated.

[0067] The control message may indicate the protection status of the port (e.g. Figure 5C In some embodiments, the control message may also indicate the usage status of the port (e.g., Figure 5C The control message may also indicate a flush of a filter database (FDB), which stores media access control (MAC) addresses learned in the transmission node. In some embodiments, the FDB may be flushed when the usage state of a port (active to standby, or standby to active) changes, or when a node failure occurs. Flushing the FDB may include flushing the learned MAC addresses on the relevant ports, or may include flushing the FDB of the entire transmission node.

[0068] The embodiments of the present disclosure also provide protection for paired links. In some embodiments, the paired links between the transmission nodes may include multiple paired links, and the control message and its copy may be transmitted on the first link and the second link of the multiple paired links respectively. For example, on the sending side of the control message, it can be broadcast on two links, with one copy on each link; on the receiving side, the control message can be received from the two paired links, one of the copies can be selected to verify whether the paired link is working properly, and sent to the DHPP module after verification.

[0069] In this article, a fault may include a service data link fault, a transmission node fault, or a pairing link fault between transmission nodes. A port fault may be regarded as a service data link fault, corresponding to a protection state of a working link fault (SF-W) or a protection link fault (SF-P). In some embodiments, the detection of a service data link fault may include physical layer fault detection, including local errors (e.g., power failure, loss of signal, loss of synchronization, local error indication) and remote errors (e.g., remote error indication). Additionally or alternatively, the detection of a service data link fault may also include, for example, IEEE802.3ah link operation and maintenance management (OAM) link monitoring and remote fault indication. Additionally or alternatively, the detection of a service data link fault may also include IEEE 802.1ag configuration connection fault management (CFM) OAM connection loss (LOC) and remote defect indication (RDI).

[0070] For transmission node failure detection, when a transmission node is cold started or unexpectedly powered off, the transmission node can use a large capacitor or a backup power supply to send a set of fast control messages to the transmission node at the opposite end in a short time, for example, multiple control messages indicating link failure (SF). In some embodiments, after the node failure is recovered, the transmitting laser at the port of the failed transmission node can be disabled until the use status of the port is determined by the DHHP module.

[0071] For paired link failure detection, the transmission node may determine that a paired link failure occurs based on a paired port that carries a control message failing, or when multiple (eg, 3) periodic control messages are lost continuously.

[0072] The following references Figures 6 to 12 The following describes an example of the working process of a dual-homing protection communication system using an embodiment of the present disclosure. These examples relate to applying an embodiment of the present disclosure to protect service data between a radio unit (RU) and a virtual distribution unit (vDU), but it should be understood that the present disclosure is not limited thereto.

[0073] As shown in the figure, the customer equipment uses a unique port to connect to two redundant transmission nodes via a splitter / combiner. The DHPP protection mechanism running on transmission nodes 1 and 2 is to protect the traffic between the RU and transmission nodes 1 and 2. In order to restore the end-to-end traffic between the RU and the vDU, MC-LAG is used on transmission nodes 1 and 2 to protect the service data between the vDU and transmission nodes 1 and 2. It should be understood that MC-LAG is an example and is not part of the DHPP protection mechanism, and other protection mechanisms are also possible.

[0074] In this example, the RU uses a unique uplink port to connect a Y-cable (including a Y-optical cable and a Y-electric cable), which splits the optical signal into two copies, each of which points to a redundant transport node. The vDU uses two ports, one connected to transport node 1 and the other connected to transport node 2. A paired link is connected between transport node 1 and transport node 2 to provide a forwarding path in the event of a link failure. In transport nodes 1 and 2, Ethernet services (such as E-LAN ​​services) are configured to provide Layer 2 forwarding between ports P1, P2, P3, and P4. In transport nodes 1 and 2, DHPP controls P1, MC-LAG 1 controls P2, and MC-LAG 2 controls P3.

[0075] The DHPP instance runs on transmission node 1, and the peer DHPP instance runs on transmission node 2. Here, the DHPP instance on transmission node 1 controls P1 on transmission node 1, which is configured as a working port. The DHPP instance on transmission node 2 controls P1 on transmission node 2, which is configured as a protection port. DHPP control messages are transmitted and received on the paired links between transmission nodes, which may share the same link as the service data, such as P4, or may use other links.

[0076] Figure 6 A schematic diagram of a DHPP system in normal conditions according to some embodiments of the present disclosure is shown. In a normal situation without any fault or external command, work no request (NR-W) > protection no request (NR-P) is defined in the priority list, so in the initial state, the working port is in an active state and forwards service data, and the protection port is in a standby state and blocked by turning off the transmit laser. Therefore, the traffic from RU to vDU passes through P1 and P2 of transmission node 1. The service data can be bidirectional, and the service data is broadcast before learning the MAC address.

[0077] Figure 7 A schematic diagram of a DHPP system with a service data link failure according to some embodiments of the present disclosure is shown. In the case of a link failure, for example, P1 of transmission node 1 detects a local error or a remote error, the DHPPs on transmission nodes 1 and 2 perform the following operations.

[0078] The DHPP on the transmission node 1 changes its own protection state to working link failure (SF-W), sets the use state of the working port to the standby state, and blocks by turning off the transmitting laser. The DHPP on the transmission node 1 can also flush the MAC addresses on the working port and the paired port, and send SF-W to the peer DHPP on the transmission node 2 through a control message.

[0079] After receiving SF-W, the DHPP on transport node 2 changes the state to "SF-W, remote", sets the protection port to active state, unblocks, and flushes the paired port and P1 by turning on the transmitter laser. The DHPP on transport node 2 also sends a protection no request (NR-P) to the peer DHPP on transport node 1.

[0080] The service data received by P2 on transmission node 1 from the vDU will be broadcast to all ports (except P2) and forwarded through P4. When P4 on transmission node 2 receives the service data, the MAC table has been flushed or refreshed, so the service data is broadcast to P1. As a result, the service from vDU to RU is restored. The service data received by P1 of transmission node 2 from RU will be broadcast to all ports (except P1) and forwarded through P4. Since the MAC address has been learned on P2, it will be forwarded to P2 of transmission node 1. As a result, the service from RU to vDU is restored. At this point, the two-way communication between RU and vDU has been restored.

[0081] Figure 8 A schematic diagram of a DHPP system with an active node failure according to some embodiments of the present disclosure is shown. In the case of an active node failure, for example, a hardware failure or power failure of transmission node 1, the DHPP on transmission nodes 1 and 2 performs the following operations.

[0082] The DHPP on transport node 1 sends out three fast node failure notification control messages (e.g., SF-W) to notify the peer DHPP on transport node 2. After receiving the node failure notification control message, the DHPP on transport node 2 changes the state to "SF-W, remote", sets the protection port to the active state, turns on the transmit laser to unblock, and sends NR-P to the peer DHPP on transport node 1 via control messages. After detecting the peer node failure, the MC-LAG on transport node 2 changes the state to active and flushes the MAC addresses learned on P2 / P3.

[0083] The service data of the RU received from P1 of transmission node 2 will be flooded to all ports (except P1) and forwarded through P2 / P3. Since the vDU is able to receive service data from two network cards (NICs), the service data from the RU to the vDU is restored through P1 and P2 / P3 of transmission node 2. After receiving the MAC address of the RU on P1, the vDU learns the MAC address of the RU on NIC 2 and starts sending service data through NIC2. After receiving the service data from the vDU, P2 of transmission node 2 forwards it to P1 according to the learned MAC address. As a result, the traffic from the vDU to the RU is restored. At this point, the two-way communication between the RU and the vDU has been restored.

[0084] Fig. 9A schematic diagram of a DHPP system with a backup node failure according to some embodiments of the present disclosure is shown. In the case of a backup node failure, for example, a hardware failure or power failure of transmission node 2, the DHPP on transmission nodes 1 and 2 performs the following operations.

[0085] The DHPP on the transmission node 2 sends out three fast node failure notification control messages (SF-P) to notify the peer DHPP on the transmission node 1. After receiving the node failure notification control message, if there is no higher priority condition or command, the DHPP on the transmission node 1 changes the state to "SF-P, remote", keeps the working port in an activated and unblocked state, keeps the sending laser on, does not flush the MAC table, and sends NR-W to the peer DHPP on the transmission node 2. Therefore, no service data is lost in both directions.

[0086] Fig.10 A schematic diagram of a DHPP system in which a DHPP control link failure occurs according to some embodiments of the present disclosure is shown. Fig.10 In the example of , the DHPP control channel uses a link different from the user service. When a DHPP control link failure is detected (link damage or control message loss), the DHPP on the transmission nodes 1 and 2 performs the following operations.

[0087] When a DHPP control link failure is detected, if there is no higher priority condition such as LO-W / LO-P command, the DHPP on transmission node 1 will change the state to pairing failure (MF). If option 1 mentioned above is used for processing (considering that the customer device has a unique port), the working port is kept active and unblocked, and the MAC table is not flushed. When a DHPP control link failure is detected, if there is no higher priority condition such as LO-W / LO-P command, the DHPP on transmission node 2 will change the state to pairing link failure (MF), and if option 1 is used for processing, the protection port is kept standby and unblocked, and the MAC table is not flushed. Therefore, no service data is lost in both directions.

[0088] Fig.11 A schematic diagram of a DHPP system in which a pairing link failure and a DHPP control link failure occur according to some embodiments of the present disclosure is shown. In the case where the DHPP control channel shares the same pairing link with the user service data, when a pairing link failure is detected (e.g., in the downlink direction), the DHPP on the transmission nodes 1 and 2 performs the following operations.

[0089] When a pair link failure is detected, if there is no higher priority condition, such as LO-W / LO-P command, the DHPP on the transmission node 1 converts the port protection state to pair failure (MF), and keeps the working port as active and unblocked, and does not flush the MAC table. When a pair link failure is detected, if there is no higher priority condition, such as LO-W / LO-P command, the DHPP on the transmission node 2 converts the port protection state to pair failure (MF), and keeps the protection port as standby and unblocked, and does not flush the MAC table. On the other side, after detecting a pair link failure, MC-LAG activates the two peer LAGs. As a result, both bidirectional services have been restored.

[0090] above Figures 6 to 11 The operation is described for a single-port client device. Fig.12 A schematic diagram of a DHPP system for a dual-port client device according to some embodiments of the present disclosure is shown. Figures 6 to 11 In the MC-LAG, the DHPP protection mechanism run by transport nodes 1 and 2 can also be used to protect the service data between transport nodes 1 and 2 and the vDU.

[0091] like Fig.12 As shown in Figure 2, the communication between RU and transmission node and between vDU and transmission node are protected by DHPP mechanism. In the communication between transmission node and vDU, vDU uses two ports, one port to transmission node 1 and the other port to transmission node 2. Figures 6 to 11 , DHPP can follow the same procedure to restore services for different failure scenarios discussed in the previous section, except that the DHPP of transport node 1 and transport node 2 can both be configured with the option of not turning off the transmit laser of the port in standby because both NICs of the vDU want to receive user traffic. DHPP can also be configured to turn off the transmit laser of the standby port. These two methods can be flexibly configured. Another difference is that the DHPP of transport node 1 and transport node 2 can both be configured with the option of converting both paired peer ports to active ports when the paired link fails, so that service data can still be forwarded through either port.

[0092] The following Table 1 shows a comparison between the DHPP protection mechanism provided by the embodiment of the present disclosure and other traditional protection mechanisms (Ethernet Linear Protection ELP, Ethernet Ring Protection ERP, MC-LAG).

[0093] Table 1

[0094]

[0095]

[0096] In some examples, the protection switching mechanism of the embodiments of the present disclosure can be implemented in two steps. In the first step, it is implemented only in one node, and the other node is responsible for reporting the failure on its side and executing the port usage status determined by the other end, but in this step, the paired link must use a protection mechanism to prevent the paired link from failing. In the second step, the proposed protection switching mechanism is implemented in both nodes in equal measure. The method proposed in this article can be used to control a single paired port, but is not limited to this, and can also be used to protect a group of paired ports, or to protect a paired service access point (SAP), where the SAP identifier can be a port ID+VLAN ID, or to protect a paired SAP group.

[0097] Fig.13 A schematic flow chart of a communication method 1300 according to some embodiments of the present disclosure is shown. In some embodiments, the method 1300 may be performed in a Figure 1 The device may be implemented at a device of any one or both of the first transmission node 110 and the second transmission node 120 .

[0098] At block 1310, at a first transmission node, a protection state of a first port of the first transmission node is determined based on at least one of at least one local request generated by the first transmission node or at least one control message from a second transmission node, wherein the first port and a second port of the second transmission node are coupled to a client device, a port function of the first port is one of a working port or a protection port, and a port function of the second port is the other of the working port or the protection port. At block 1320, a usage state of the first port with respect to the client device is determined based on the protection state and the port function of the first port, wherein the usage state includes activation or standby.

[0099] In some embodiments, each of the at least one local request may indicate a protection state in a set of protection states, and the at least one control message may include a remote request indicating a protection state in a set of protection states for the second port, and the set of protection states each have an associated priority. The device may also determine the protection state of the first port by: determining a request with a highest priority among the at least one local request and the remote request; and determining the protection state of the first port based on a previous protection state of the first port and the request with the highest priority.

[0100] In some embodiments, a set of protection states may include at least one of the following: working lock; protection lock; paired link failure; working forced switching; protection forced switching; working link failure; protection link failure; working link degradation; protection link degradation; working manual switching; protection manual switching; working without request; or protection without request.

[0101] In some embodiments, the priority of a group of protection states satisfies at least one of the following: the priority of working lock and protection lock is higher than the priority of paired link failure, and the priority of paired link failure is higher than the priority of working forced switching and protection forced switching; or the priority of working lock and protection lock is higher than the priority of working forced switching and protection forced switching, and the priority of working forced switching and protection forced switching is higher than the priority of paired link failure.

[0102] In some embodiments, the device may determine the request with the highest priority by: determining a local request with the highest priority among at least one local request based on the priority; and determining the request with the highest priority among the determined local requests and remote requests.

[0103] In some embodiments, determining the protection status of the first port may also include: when the local request and the remote request have the same priority, based on the port function of the first port being a working port, determining the usage status of the first port to be activated; or based on the port function of the first port being a protection port, determining the usage status of the first port to be standby.

[0104] In some embodiments, the device may further: send a control message to the second transmission node based on the protection state of the first port, so that the usage state of the second port is determined based on at least the control message.

[0105] In some embodiments, the first transmission node and the second transmission node may be coupled via at least one paired link, and the control message is transmitted on a link in the at least one paired link.

[0106] In some embodiments, the device may also determine the usage status of the first port and the second port based on the indication in the control message when the request with the highest priority indicates that at least one paired link fails.

[0107] In some embodiments, determining the use status of the first port and the second port may include one of the following: keeping the use status of the first port and the second port unchanged; or determining that the use status of the first port and the second port are both activated.

[0108] In some embodiments, the at least one paired link may include a plurality of paired links, and the control information and the copy thereof may be transmitted on a first link and a second link of the plurality of paired links, respectively.

[0109] In some embodiments, the control message may indicate at least one of the following: a protection status of a port; a usage status of a port; or a flushing of a filter database (FDB).

[0110] In some embodiments, the control message may be transmitted via at least one of: an Ethernet header; an Internet Protocol (IP) header; a Multi-Protocol Label Switching (MPLS) header; or an Optical Transport Network (OTN) or Synchronous Digital Hierarchy (SDH) container.

[0111] In some embodiments, the device may also forward packets from or to the client device at the first port and enable media access control (MAC) address learning based on the usage status of the first port being determined to be activated; or discard packets at the first port based on the usage status of the first port being determined to be standby.

[0112] In some embodiments, a port of a customer device may be coupled to a first port and a second port via a splitter / combiner, and the device may also: turn off a transmitting laser at the first port based on the usage status of the first port being determined to be standby; or turn on a transmitting laser at the first port based on the usage status of the first port being determined to be activated.

[0113] In some embodiments, the device may further refresh the MAC address learned on the first port and at least one paired port of the first transmission node connected to the second transmission node based on the change in the usage status of the first port.

[0114] In some embodiments, the device may also detect at least one of the following: a service data link failure; a transmission node failure; or a pairing link failure between transmission nodes.

[0115] In some embodiments, detection of service data link failures may be based on at least one of: physical layer fault detection; operations maintenance management (OAM) link monitoring and remote fault indication; or configuration connectivity fault management (CFM) OAM loss of connection (LOC) and remote defect indication.

[0116] In some embodiments, the device may further disable a transmission laser at a port of the failed transmission node when the failed transmission node in the first transmission node or the second transmission node recovers until the usage status of the port is determined.

[0117] In some embodiments, the first transmission node and the second transmission node may be included in the same network device, or respectively included in different network devices.

[0118] In some embodiments, the port function of the first port can be a working port and the previous usage state of the first port is activation, and the device can also change the protection state of the first port to indicate a working link failure based on detecting a link failure between the first port and the customer device; change the usage state of the first port to standby; flush the MAC address on the first port and the paired port to the second node; and send a control message indicating a working link failure to the second transmission node.

[0119] In some embodiments, the port function of the first port can be a protection port and the previous usage status of the first port is standby, and the device can also: change the protection status of the first port to activated based on receiving a control message indicating a working link failure from the second transmission node; and flush the MAC address on the first port and the paired port to the second node.

[0120] In some embodiments, where the port function of the first port may be a working port and the previous usage status of the first port is activated, the device may also send at least one control message indicating a working node failure to the second transmission node based on detecting a failure of the first transmission node.

[0121] In some embodiments, the port function of the first port can protect the port and the previous usage status of the first port is standby, and the device can also: based on receiving at least one control message indicating a working node failure from the second transmission node, change the usage status of the first port and a third port communicatively coupled to another client device to activation, wherein business data is transmitted between the other client device and the client device; and flush the MAC addresses on the first port and the third port.

[0122] In some embodiments, the port function of the first port may be a protection port and the usage status of the first port is standby, and the device may also: based on detecting a failure of the first transmission node, send at least one control message indicating a protection node failure to the second transmission node.

[0123] In some embodiments, the port function of the first port may be a working port and the usage status of the first port is activated, and the device may also maintain the usage status of the first port as activated based on receiving at least one control message indicating a protection node failure from the second transmission node.

[0124] In some embodiments, the client device has two ports for transmitting different business data to a first port and a second port, respectively, and the device may also perform at least one of the following: based on the usage status of the first port being determined as standby, keeping the transmitting laser of the first port turned on; or based on detecting a pairing link failure between the first transmission node and the second transmission node, determining the usage status of the first port and the second port as activated.

[0125] In some embodiments, the apparatus further comprises means for performing other steps in some embodiments of method 1300. In some embodiments, the means comprises at least one processor and at least one memory storing computer program code. The at least one memory and the computer program code are configured to, together with the at least one processor, cause execution of the apparatus.

[0126] In some example embodiments, an apparatus capable of performing method 1300 may include a component for performing each step of method 1300. The component may be implemented in any suitable form. For example, the component may be implemented in a circuit or a software module.

[0127] The apparatus may include a component for determining, at a first transmission node, a protection state of a first port of the first transmission node based on at least one of at least one local request generated by the first transmission node or at least one control message from a second transmission node, wherein the first port and the second port of the second transmission node are coupled to a client device, a port function of the first port is one of a working port or a protection port, and a port function of the second port is the other of the working port or the protection port. The apparatus may also include a component for determining a usage state of the first port with respect to the client device based on the protection state and the port function of the first port, wherein the usage state includes activation or standby.

[0128] In some embodiments, each of the at least one local request may indicate a protection state in a set of protection states, and a control message in the at least one control message may include a remote request indicating a protection state in a set of protection states for the second port, and the set of protection states each have an associated priority. The component for determining the protection state of the first port may include: a component for determining a request with a highest priority among the at least one local request and the remote request; and a component for determining the protection state of the first port based on a previous protection state of the first port and the request with the highest priority.

[0129] In some embodiments, a set of protection states may include at least one of the following: working lock; protection lock; paired link failure; working forced switching; protection forced switching; working link failure; protection link failure; working link degradation; protection link degradation; working manual switching; protection manual switching; working without request; or protection without request.

[0130] In some embodiments, the priority of a group of protection states satisfies at least one of the following: the priority of working lock and protection lock is higher than the priority of paired link failure, and the priority of paired link failure is higher than the priority of working forced switching and protection forced switching; or the priority of working lock and protection lock is higher than the priority of working forced switching and protection forced switching, and the priority of working forced switching and protection forced switching is higher than the priority of paired link failure.

[0131] In some embodiments, the component for determining the request with the highest priority may include: a component for determining, based on the priority, a local request with the highest priority among at least one local request; and a component for determining the request with the highest priority among the determined local requests and remote requests.

[0132] In some embodiments, the component for determining the protection status of the first port may also include: a component for determining that the usage status of the first port is activated based on the port function of the first port being a working port when the local request and the remote request have the same priority; or a component for determining that the usage status of the first port is standby based on the port function of the first port being a protection port.

[0133] In some embodiments, the apparatus may further include a component for sending a control message to the second transmission node based on the protection state of the first port, so that the usage state of the second port is determined based at least on the control message.

[0134] In some embodiments, the first transmission node and the second transmission node may be coupled via at least one paired link, and the control message is transmitted on a link in the at least one paired link.

[0135] In some embodiments, the apparatus may further include means for determining a usage status of the first port and the second port based on an indication in the control message if the request with the highest priority indicates that at least one paired link fails.

[0136] In some embodiments, the component for determining the use status of the first port and the second port may include one of the following: a component for keeping the use status of the first port and the second port unchanged; or a component for determining that the use status of the first port and the second port are both activated.

[0137] In some embodiments, the at least one paired link may include a plurality of paired links, and the control information and the copy thereof may be transmitted on a first link and a second link of the plurality of paired links, respectively.

[0138] In some embodiments, the control message may indicate at least one of the following: a protection status of a port; a usage status of a port; or a flushing of a filter database (FDB).

[0139] In some embodiments, the control message may be transmitted via at least one of: an Ethernet header; an Internet Protocol (IP) header; a Multi-Protocol Label Switching (MPLS) header; or an Optical Transport Network (OTN) or Synchronous Digital Hierarchy (SDH) container.

[0140] In some embodiments, the device may also include a component for forwarding packets from or to the client device at the first port and enabling media access control (MAC) address learning based on the usage status of the first port being determined to be activated; or a component for discarding packets at the first port based on the usage status of the first port being determined to be standby.

[0141] In some embodiments, a port of a customer device may be coupled to a first port and a second port via a splitter / combiner, and the apparatus may further include: a component for turning off a transmitting laser at the first port based on a usage status of the first port being determined to be standby; or a component for turning on a transmitting laser at the first port based on a usage status of the first port being determined to be activated.

[0142] In some embodiments, the apparatus may further include a component for refreshing a MAC address learned on the first port and at least one paired port of the first transmission node connected to the second transmission node based on a change in a usage status of the first port.

[0143] In some embodiments, the device may also detect at least one of the following: a service data link failure; a transmission node failure; or a pairing link failure between transmission nodes.

[0144] In some embodiments, the detection of a service data link failure may be based on at least one of: physical layer fault detection; Operation Maintenance Management (OAM) link monitoring and remote fault indication; or

[0145] Configure Connectivity Fault Management (CFM) OAM Loss of Connectivity (LOC) and Remote Defect Indications.

[0146] In some embodiments, the device may further disable a transmission laser at a port of the failed transmission node when the failed transmission node in the first transmission node or the second transmission node recovers until the usage status of the port is determined.

[0147] In some embodiments, the first transmission node and the second transmission node may be included in the same network device, or respectively included in different network devices.

[0148] In some embodiments, the port function of the first port may be a working port and the previous usage state of the first port is activation, and the apparatus may further include: a component for changing the protection state of the first port to indicate a working link failure based on detecting a link failure between the first port and the customer device; a component for changing the usage state of the first port to standby; a component for flushing the MAC address on the first port and the paired port to the second node; and a component for sending a control message indicating a working link failure to the second transmission node.

[0149] In some embodiments, the port function of the first port can be a protection port and the previous usage status of the first port is standby, and the device may also include: a component for changing the protection status of the first port to activated based on receiving a control message indicating a working link failure from the second transmission node; and a component for flushing the MAC address on the first port and the paired port to the second node.

[0150] In some embodiments, where the port function of the first port may be a working port and the previous usage status of the first port is activated, the device may further include: a component for sending at least one control message indicating a working node failure to a second transmission node based on detecting a failure of the first transmission node.

[0151] In some embodiments, the port function of the first port can protect the port and the previous usage status of the first port is standby, and the device can also: be used to change the usage status of the first port and a third port communicatively coupled to another client device to activated based on at least one control message indicating a working node failure received from a second transmission node, wherein the other client device and the client device transmit business data between the components; and a component for flushing the MAC addresses on the first port and the third port.

[0152] In some embodiments, the port function of the first port may be a protection port and the usage status of the first port may be standby. The device may also include: a component for sending at least one control message indicating a protection node failure to the second transmission node based on detecting a failure of the first transmission node.

[0153] In some embodiments, the port function of the first port can be a working port and the usage status of the first port is activated. The device may also include: a component for maintaining the usage status of the first port as activated based on receiving at least one control message indicating a protection node failure from the second transmission node.

[0154] In some embodiments, the client device has two ports for transmitting different business data to a first port and a second port, respectively. The device may also include a component for performing at least one of the following: based on the usage status of the first port being determined as standby, keeping the transmitting laser of the first port turned on; or based on detecting a pairing link failure between the first transmission node and the second transmission node, determining the usage status of the first port and the second port as activated.

[0155] In some embodiments, the apparatus further comprises means for performing other steps in some embodiments of method 1300. In some embodiments, the means comprises at least one processor and at least one memory storing computer program code. The at least one memory and the computer program code are configured to, together with the at least one processor, cause execution of the apparatus.

[0156] Fig.14 1 is a simplified block diagram of an electronic device 1400 suitable for implementing embodiments of the present disclosure. The device 1400 may be provided to implement a communication device, such as Figure 1 The device 1400 includes one or more processors 1410, one or more memories 1420 coupled to the processor 1410, and one or more communication modules 1440 coupled to the processor 1410.

[0157] The communication module 1440 is used for two-way communication. For example, the communication module 1440 may include a transmitter, a receiver, or a transceiver used in the embodiments of the present disclosure. The communication interface may represent any interface necessary for communicating with other network elements.

[0158] Processor 1410 may be of any type suitable for the local technology network and may include, but is not limited to, one or more of a general purpose computer, a special purpose computer, a microcontroller, a digital signal controller (DSP), and a controller-based multi-core controller architecture. Device 1400 may have multiple processors, such as application specific integrated circuit chips, which are time-slaved to a clock synchronized with a main processor.

[0159] The memory 1420 may include one or more non-volatile memories and one or more volatile memories. Examples of non-volatile memories include, but are not limited to, read-only memory (ROM) 1424, erasable programmable read-only memory (EPROM), flash memory, hard disk, compact disk (CD), digital video disk (DVD), and other magnetic storage and / or optical storage. Examples of volatile memories include, but are not limited to, random access memory (RAM) 1422 and other volatile memories that do not persist over the duration of a power outage.

[0160] Computer program 1430 includes computer executable instructions executed by associated processor 1410. Program 1430 may be stored in ROM 1420. Processor 1410 may perform any suitable actions and processes by loading program 1430 into RAM 1420.

[0161] The embodiment of the present disclosure can be implemented with the help of program 1430, so that the device 1400 can execute the Figure 2 and Fig.13 Any process of the present disclosure discussed. The embodiments of the present disclosure may also be implemented by hardware or by a combination of software and hardware.

[0162] In some embodiments, the program 1430 may be tangibly embodied in a computer-readable medium that may be included in the device 1400 (such as in the memory 1420) or other storage device accessible by the device 1400. The program 1430 may be loaded from the computer-readable medium to the RAM 1422 for execution. The computer-readable medium may include any type of tangible non-volatile memory, such as ROM, EPROM, flash memory, hard disk, CD, DVD, etc.

[0163] Figure 6 An example of a computer readable medium 1500 in the form of a CD or DVD is shown. The computer readable medium has a program 1430 stored thereon.

[0164] In general, various embodiments of the present disclosure may be implemented in hardware or dedicated circuits, software, logic, or any combination thereof. Some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software, which may be performed by a controller, microprocessor, or other computing device. Although various aspects of the embodiments of the present disclosure are shown and described as block diagrams, flow charts, or using some other graphical representation, it should be understood that the blocks, devices, systems, techniques, or methods described herein may be implemented as, by way of non-limiting example, hardware, software, firmware, dedicated circuits or logic, general purpose hardware or a controller or other computing device, or some combination thereof.

[0165] The present disclosure also provides at least one computer program product tangibly stored on a non-transitory computer-readable storage medium. The computer program product includes computer executable instructions, such as instructions included in a program module, which are executed in a device on a real or virtual processor of a target to perform the above-referenced Fig.13Method 1300. Typically, program modules include routines, programs, libraries, objects, classes, components, data structures, etc. that perform specific tasks or implement specific abstract data types. In various embodiments, the functionality of program modules can be combined or divided between program modules as needed. Machine executable instructions for program modules can be executed in local or distributed devices. In distributed devices, program modules can be located in local and remote storage media.

[0166] The computer program code for realizing the method of the present disclosure can be written in one or more programming languages. These computer program codes can be provided to the processor of general-purpose computer, special-purpose computer or other programmable data processing device, so that the program code, when being executed by computer or other programmable data processing device, causes the function / operation specified in flow chart and / or block diagram to be implemented. The program code can be executed completely on computer, partly on computer, as independent software package, partly on computer and partly on remote computer or completely on remote computer or server.

[0167] In the context of the present disclosure, computer program codes or related data may be carried by any appropriate carrier to enable a device, apparatus or processor to perform the various processes and operations described above. Examples of carriers include signals, computer readable media, and the like. Examples of signals may include electrical, optical, radio, acoustic or other forms of propagation signals, such as carrier waves, infrared signals, and the like.

[0168] A computer-readable medium may be any tangible medium containing or storing a program for or about an instruction execution system, device or equipment. A computer-readable medium may be a computer-readable signal medium or a computer-readable storage medium. A computer-readable medium may include, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared or semiconductor system, device or equipment, or any suitable combination thereof. A more detailed example of a computer-readable storage medium includes an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical storage device, a magnetic storage device, or any suitable combination thereof. As used herein, the term "non-transient" or "non-transient" is a limitation on the medium itself (i.e., tangible, not a signal), rather than a limitation on the persistence of data storage (e.g., RAM and ROM).

[0169] In addition, although the operation of the method of the present disclosure is described in a particular order in the accompanying drawings, this does not require or imply that these operations must be performed in this particular order, or that all the operations shown must be performed to achieve the desired result. On the contrary, the steps depicted in the flow chart can change the order of execution. Additionally or alternatively, some steps can be omitted, multiple steps can be combined into one step for execution, and / or one step can be decomposed into multiple steps for execution. It should also be noted that the features and functions of two or more devices according to the present disclosure can be embodied in one device. Conversely, the features and functions of a device described above can be further divided into being embodied by multiple devices.

[0170] Although the present disclosure has been described with reference to several specific embodiments, it should be understood that the present disclosure is not limited to the specific embodiments disclosed. The present disclosure is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

Claims

1. A device comprising: at least one processor; as well as at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus to at least: At a first transmission node, determining a protection state of a first port of the first transmission node based on at least one of at least one local request generated by the first transmission node or at least one control message from a second transmission node, wherein the first port and a second port of the second transmission node are coupled to a client device, a port function of the first port is one of a working port or a protection port, and a port function of the second port is the other of a working port or a protection port; as well as Based on the protection status and the port function of the first port, a usage status of the first port with respect to the client device is determined, wherein the usage status includes activation or standby.

2. The apparatus of claim 1 , wherein each of the at least one local request indicates a protection state in a set of protection states, a control message in the at least one control message comprises a remote request indicating a protection state in the set of protection states for the second port, the set of protection states each having an associated priority, and the apparatus is caused to determine the protection state of the first port by: determining a request having a highest priority among the at least one local request and the remote request; and The protection state of the first port is determined based on a previous protection state of the first port and the request with the highest priority.

3. The device according to claim 2, wherein: The set of protection states includes at least one of the following: working lock; protection lock; paired link failure; working forced switching; protection forced switching; working link failure; protection link failure; working link degradation; protection link degradation; working manual switching; protection manual switching; working without request; or protection without request.

4. The device according to claim 3, wherein: The priority of the set of protection states satisfies at least one of the following: The priority of the working lock and the protection lock is higher than the priority of the paired link failure, and the priority of the paired link failure is higher than the priority of the working forced switching and the protection forced switching: or The priorities of the working lock and the protection lock are higher than the priorities of the working forced switching and the protection forced switching, and the priorities of the working forced switching and the protection forced switching are higher than the priority of the paired link failure.

5. An apparatus according to any one of claims 2 to 4, wherein the apparatus is caused to determine the request with the highest priority by: Based on the priority, determining a local request having a highest priority among the at least one local request; and The request with the highest priority is determined among the determined local requests and the remote requests.

6. The apparatus of claim 5, wherein determining the protection status of the first port further comprises: In the case where the priorities of the local request and the remote request are the same, Based on the port function of the first port being a working port, determining that the use status of the first port is activated; or Based on the fact that the port function of the first port is a protection port, it is determined that the use status of the first port is standby.

7. The apparatus according to any one of claims 1 to 6, wherein the instructions, when executed by the at least one processor, further cause the apparatus to: Based on the protection state of the first port, a control message is sent to the second transmission node, so that the use state of the second port is determined based on at least the control message.

8. The apparatus according to any one of claims 1 to 7, wherein the first transmission node and the second transmission node are coupled via at least one paired link, and the control message is transmitted on a link in the at least one paired link.

9. The apparatus of claim 8, wherein the instructions, when executed by the at least one processor, further cause the apparatus to: In a case where the request with the highest priority indicates that the at least one paired link fails, the usage status of the first port and the second port is determined based on the indication in the control message.

10. The apparatus of claim 9, wherein determining the usage status of the first port and the second port comprises one of the following: Keeping the usage status of the first port and the second port unchanged; or It is determined that the usage status of the first port and the second port are both activated.

11. The apparatus according to any one of claims 7 to 10, wherein the at least one paired link comprises a plurality of paired links, and the control message and its copy are transmitted on a first link and a second link of the plurality of paired links, respectively.

12. The apparatus according to any one of claims 1 to 11, wherein the control message indicates at least one of the following: The protection status of the port; The usage status of the port; or Flush the Filter Database (FDB).

13. The apparatus according to any one of claims 1 to 12, wherein the control message is transmitted via at least one of the following: Ethernet header; Internet Protocol (IP) header; Multiprotocol Label Switching (MPLS) header; or Optical Transport Network (OTN) or Synchronous Digital Hierarchy (SDH) container.

14. The apparatus of any one of claims 1 to 13, wherein the instructions, when executed by the at least one processor, further cause the apparatus to: forwarding packets from or to the client device at the first port and enabling media access control (MAC) address learning based on the usage status of the first port being determined to be active; or Based on the usage status of the first port being determined as standby, a packet at the first port is discarded.

15. The apparatus according to any one of claims 1 to 14, wherein one port of the client device is coupled to the first port and the second port via an optical splitter / combiner, and the instructions, when executed by the at least one processor, further cause the apparatus to: Based on the usage status of the first port being determined as standby, turning off the transmission laser at the first port; or Based on the use status of the first port being determined to be active, the transmit laser at the first port is turned on.

16. The apparatus of any one of claims 1 to 14, wherein the instructions, when executed by the at least one processor, further cause the apparatus to: Based on the change in the use status of the first port, the MAC address learned on the first port and at least one paired port in the first transmission node connected to the second transmission node is refreshed.

17. The apparatus of any one of claims 1 to 16, wherein the instructions, when executed by the at least one processor, further cause the apparatus to detect at least one of the following: Service data link failure; A transmission node fails; or The paired link between the transport nodes fails.

18. The apparatus of claim 17, wherein the detection of the service data link failure is based on at least one of the following: Physical layer fault detection; Link Operations and Administration (OAM) link monitoring and remote fault indication; or Configure Connectivity Fault Management (CFM) OAM Loss of Connectivity (LOC) and Remote Defect Indications.

19. The apparatus of claim 17, wherein the instructions, when executed by the at least one processor, further cause the apparatus to: In a case where a failed transmission node among the first transmission node or the second transmission node is recovered, a transmission laser at a port of the failed transmission node is disabled until a usage state of the port is determined. 20 . The apparatus according to claim 1 , wherein the first transmission node and the second transmission node are included in the same network device, or are respectively included in different network devices.

21. The apparatus according to any one of claims 1 to 20, wherein the port function of the first port is a working port and the previous use state of the first port is activation, and the instructions, when executed by the at least one processor, further cause the apparatus to: Based on detecting a link failure between the first port and the client device, changing a protection state of the first port to indicate a working link failure; Changing the use state of the first port to standby; Flushing the MAC addresses on the first port and the paired port to the second node; as well as A control message indicating a working link failure is sent to the second transmission node.

22. The apparatus according to any one of claims 1 to 18, wherein the port function of the first port is a protection port and the previous use state of the first port is standby, and when the instructions are executed by the at least one processor, the apparatus further: Based on receiving a control message indicating a working link failure from the second transmission node, changing the protection state of the first port to activated; and The MAC address on the first port and the paired port to the second node is flushed.

23. The apparatus according to any one of claims 1 to 18, wherein the port function of the first port is a working port and a previous use state of the first port is activation, the instructions, when executed by the at least one processor, further cause the apparatus to: Based on detecting a failure of the first transmission node, at least one control message indicating a working node failure is sent to the second transmission node.

24. The apparatus according to any one of claims 1 to 18, wherein the port function of the first port is a protection port and the previous use state of the first port is standby, and when the instructions are executed by the at least one processor, the apparatus further: Based on receiving at least one control message indicating a working node failure from the second transmission node, changing the use state of the first port and a third port communicatively coupled to another client device to activation, wherein service data is transmitted between the another client device and the client device; and The MAC addresses on the first port and the third port are flushed.

25. The device according to any one of claims 1 to 18, wherein the port function of the first port is a protection port and the use status of the first port is standby, and when the instruction is executed by the at least one processor, the device further: Based on detecting a failure of the first transmission node, at least one control message indicating a protection node failure is sent to the second transmission node.

26. The apparatus according to any one of claims 1 to 18, wherein the port function of the first port is a working port and the use state of the first port is activated, and when the instructions are executed by the at least one processor, the apparatus further: Based on receiving at least one control message indicating a protection node failure from the second transmission node, the use state of the first port is maintained as activated.

27. The apparatus according to any one of claims 19 to 24, wherein the client device has two ports for transmitting different service data to the first port and the second port respectively, and when the instructions are executed by the at least one processor, the apparatus further performs at least one of the following: Based on the usage status of the first port being determined as standby, keeping the sending laser of the first port turned on or off; or Based on detecting a paired link failure between the first transmission node and the second transmission node, the use status of the first port and the second port is determined to be activated.

28. A method comprising: At a first transmission node, determining a protection state of a first port of the first transmission node based on at least one of at least one local request generated by the first transmission node or at least one control message from a second transmission node, wherein the first port and a second port of the second transmission node are coupled to a client device, a port function of the first port is one of a working port or a protection port, and a port function of the second port is the other of a working port or a protection port; as well as Based on the protection status and the port function of the first port, a usage status of the first port with respect to the client device is determined, wherein the usage status includes activation or standby.

29. An apparatus comprising: means for determining, at a first transmission node, a protection state of a first port of the first transmission node based on at least one of at least one local request generated by the first transmission node or at least one control message from a second transmission node, wherein the first port and a second port of the second transmission node are coupled to a client device, a port function of the first port is one of a working port or a protection port, and a port function of the second port is the other of a working port or a protection port; as well as means for determining a usage status of the first port with respect to the client device based on the protection status and the port function of the first port, wherein the usage status comprises active or standby.

30. A computer-readable medium having instructions stored thereon, which when executed by a device causes the device to at least perform: At a first transmission node, determining a protection state of a first port of the first transmission node based on at least one of at least one local request generated by the first transmission node or at least one control message from a second transmission node, wherein the first port and a second port of the second transmission node are coupled to a client device, a port function of the first port is one of a working port or a protection port, and a port function of the second port is the other of a working port or a protection port; and Based on the protection status and the port function of the first port, a usage status of the first port with respect to the client device is determined, wherein the usage status includes activation or standby.

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