Method for reallocating stream control transport protocol sessions in virtualized central unit

Abstract

A method for reallocating stream control transport protocol sessions in a virtualized central unit is disclosed. The method may comprise the steps of: receiving state information from an OAM entity; on the basis of the state information, reallocating, to a second entity, a first portion of session information for one or more SCTP connections managed by a third entity; transmitting the reallocated first portion of the session information to the second entity; and receiving, from the second entity, completion information indicating that an SCTP reconnection of the second entity has been completed.

Description

A method for reassigning stream control transport protocol sessions in a virtualization central unit.

[0001] The present disclosure relates to virtualized networks, and more particularly, to a method for reallocating stream control transport protocol sessions in a virtualized central unit.

[0002] In the communications industry, technology for virtualized Radio Access Networks (RANs), or vRANs, is rapidly growing. Conventional hardware-based RANs required specialized hardware to perform each communication function. Consequently, mobile carriers had to build RANs using hardware configurations from the same manufacturer due to issues such as interoperability. However, vRANs are software-based, not hardware-based, and their communication functions can be performed through software configurations. In other words, vRANs do not require specialized hardware to perform communication functions, and their software configurations can be run on general-purpose servers to perform communication functions. Consequently, mobile carriers can build vRANs using products from various manufacturers, rather than being tied to a single manufacturer's product.

[0003] 5G wireless communication technology defines a wide frequency band to enable fast transmission speeds and new services, and can be implemented not only in the sub-6GHz frequency band such as 3.5 gigahertz (3.5GHz), but also in the ultra-high frequency band called millimeter wave (mmWave) such as 28GHz and 39GHz ('Above 6GHz'). In addition, for 6G wireless communication technology, which is called the system after 5G communication (Beyond 5G), implementation in the terahertz band (for example, the 3 terahertz (3THz) band at 95GHz) is being considered to achieve a transmission speed that is 50 times faster than 5G wireless communication technology and an ultra-low latency time that is reduced to one-tenth.

[0004] In the early stages of 5G wireless communication technology, the goal is to support services and satisfy performance requirements for enhanced Mobile Broadband (eMBB), Ultra-Reliable Low-Latency Communications (URLLC), and massive Machine-Type Communications (mMTC). These include beamforming and massive MIMO to mitigate path loss of radio waves in ultra-high frequency bands and increase the transmission distance of radio waves, support for various numerologies (such as operation of multiple subcarrier intervals) and dynamic operation of slot formats for efficient use of ultra-high frequency resources, initial access technology to support multi-beam transmission and wideband, definition and operation of BWP (Bidth Part), new channel coding methods such as LDPC (Low Density Parity Check) codes for large-capacity data transmission and Polar Code for reliable transmission of control information, and L2 pre-processing (L2). Standardization has been made for network slicing, which provides dedicated networks specialized for specific services, and pre-processing.

[0005] Currently, discussions are underway to improve and enhance the initial 5G wireless communication technology in consideration of the services that 5G wireless communication technology was intended to support, and physical layer standardization is in progress for technologies such as V2X (Vehicle-to-Everything) to help autonomous vehicles make driving decisions and increase user convenience based on their own location and status information transmitted by vehicles, NR-U (New Radio Unlicensed) for the purpose of system operation that complies with various regulatory requirements in unlicensed bands, NR terminal low power consumption technology (UE Power Saving), Non-Terrestrial Network (NTN), which is direct terminal-satellite communication to secure coverage in areas where communication with terrestrial networks is impossible, and Positioning.

[0006] In addition, standardization of radio interface architecture / protocols for technologies such as the Industrial Internet of Things (IIoT) to support new services through linkage and convergence with other industries, IAB (Integrated Access and Backhaul) to provide nodes for expanding network service areas by integrating wireless backhaul links and access links, Mobility Enhancement technology including Conditional Handover and Dual Active Protocol Stack (DAPS) handover, and 2-step random access (2-step RACH for NR) to simplify random access procedures is also in progress, and standardization of system architecture / services for 5G baseline architecture (e.g., Service-based Architecture, Service-based Interface) for grafting Network Functions Virtualization (NFV) and Software-Defined Networking (SDN) technologies, and Mobile Edge Computing (MEC) that provides services based on the location of the terminal is also in progress.

[0007] Once these 5G wireless communication systems are commercialized, an explosive increase in connected devices will be connected to the communication network, necessitating enhanced functionality and performance of 5G wireless communication systems and integrated operation of these connected devices. To this end, new research will be conducted on improving 5G performance and reducing complexity, supporting AI services, supporting metaverse services, and drone communications by utilizing eXtended Reality (XR), Artificial Intelligence (AI), and Machine Learning (ML) to efficiently support Augmented Reality (AR), Virtual Reality (VR), and Mixed Reality (MR).

[0008] In addition, the development of these 5G wireless communication systems includes new waveforms to ensure coverage in the terahertz band of 6G wireless communication technology, multi-antenna transmission technologies such as Full Dimensional MIMO (FD-MIMO), Array Antenna, and Large Scale Antenna, metamaterial-based lenses and antennas to improve the coverage of terahertz band signals, high-dimensional spatial multiplexing technology using Orbital Angular Momentum (OAM), Reconfigurable Intelligent Surface (RIS) technology, as well as full duplex technology to improve the frequency efficiency and system network of 6G wireless communication technology, satellite, AI (Artificial Intelligence) from the design stage and AI-based communication technology that realizes system optimization by internalizing end-to-end AI support functions, and ultra-high-performance communication and computing resources to provide services with complexity that goes beyond the limits of terminal computing capabilities. It can serve as a basis for the development of next-generation distributed computing technologies that can be realized by utilizing them.

[0009] A method performed by a first entity managing one or more Stream Control Transmission Protocol (SCTP) associations in a virtualized Central Unit (vCU) according to one embodiment of the present disclosure may include: receiving status information from an Operation Administration Maintenance (OAM) entity; reallocating a first portion of session information for one or more SCTP associations managed by a third entity to a second entity based on the status information; transmitting the first portion of the reallocated session information to the second entity; and receiving completion information from the second entity indicating that the SCTP reassociation of the second entity has been completed.

[0010] A method performed by a first entity for managing one or more SCTP connections in a virtualized central unit according to one embodiment of the present disclosure may include: receiving state information from an OAM entity; initiating a termination procedure based on the state information; receiving information indicating that a second entity has been selected as a leader; and providing session information of the first entity and session information of a third entity to the second entity.

[0011] A method performed by a first entity for managing one or more SCTP connections in a virtualization central unit according to one embodiment of the present disclosure may include: receiving state information from an OAM entity; receiving reallocated session information for the first entity from a second entity based on a target of the state information being a third entity; performing SCTP reconnection based on the reallocated session information; and transmitting a message indicating completion of SCTP reconnection to the second entity.

[0012] FIG. 1 illustrates a block diagram of a system including a virtualized central unit-control plane according to one embodiment of the present disclosure.

[0013] FIGS. 2A and 2B illustrate a scaling-in event of a connection management entity according to one embodiment of the present disclosure.

[0014] FIGS. 3A and 3B illustrate a failure event of a connection management entity according to one embodiment of the present disclosure.

[0015] FIG. 4 illustrates a method for at least partially reallocating session information between entities within a virtualized central unit-control plane according to one embodiment of the present disclosure.

[0016] FIG. 5 illustrates a method for at least partially reallocating session information between entities within a virtualized central unit-control plane according to one embodiment of the present disclosure.

[0017] FIG. 6 illustrates a method for at least partially reallocating session information between entities within a virtualized central unit-control plane according to one embodiment of the present disclosure.

[0018] FIG. 7 illustrates a method for at least partially reallocating session information between entities within a virtualized central unit-control plane according to one embodiment of the present disclosure.

[0019] FIG. 8 illustrates a method for at least partially reallocating session information by a connection management entity according to one embodiment of the present disclosure.

[0020] FIG. 9 illustrates a method for managing session information by a connection management entity according to one embodiment of the present disclosure.

[0021] FIG. 10 illustrates a method for at least partially reallocating session information by a connection management entity according to one embodiment of the present disclosure.

[0022] FIG. 11 illustrates a method for at least partially reallocating session information by a connection management entity according to one embodiment of the present disclosure.

[0023] FIG. 12 illustrates a block diagram of a server device according to one embodiment of the present disclosure.

[0024] This disclosure may be subject to various modifications and various embodiments. Specific embodiments are illustrated in the drawings and described in detail. However, this is not intended to limit the disclosure to specific embodiments, but rather to encompass all modifications, equivalents, and alternatives falling within the spirit and technical scope of the disclosure.

[0025] When describing embodiments, detailed descriptions of related known technologies are omitted if they are deemed to unnecessarily obscure the main point. Furthermore, numbers (e.g., "first," "second," etc.) used in the description of embodiments are merely identifiers used to distinguish one component from another.

[0026] The terms used in this disclosure are selected from widely used, common terms, taking into account the functions of the disclosure. However, these terms may vary depending on the intentions of those skilled in the art, precedents, the emergence of new technologies, etc. Furthermore, in certain cases, terms may be arbitrarily selected by the applicant, in which case their meanings will be described in detail in the relevant description. Therefore, the terms used in this disclosure should not be defined simply as names, but rather based on the meanings of the terms and the overall content of the disclosure.

[0027] Singular expressions may include plural expressions unless the context clearly indicates otherwise. Terms used herein, including technical or scientific terms, have the same meaning as commonly understood by a person of ordinary skill in the art described herein. Furthermore, terms containing ordinal numbers, such as "first" or "second," used herein may be used to describe various components, but such components should not be limited by such terms. Such terms are used solely to distinguish one component from another.

[0028] When a part of the specification is said to "include" a component, this does not exclude other components, but rather implies the inclusion of other components, unless otherwise specifically stated. Furthermore, terms such as "unit (or part)" and "module" used in the specification mean a unit that processes at least one function or operation, which may be implemented in hardware, software, or a combination of hardware and software.

[0029] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the attached drawings so that those skilled in the art can easily practice the present disclosure. However, the present disclosure may be implemented in various different forms and is not limited to the embodiments described herein. In addition, in the drawings, parts that are not related to the description are omitted to clearly explain the present disclosure, and similar parts are designated with similar reference numerals throughout the specification. In addition, the reference numerals used in each drawing are only for the purpose of describing each drawing, and different reference numerals used in different drawings do not indicate different elements.

[0030] Throughout the specification, when a part is said to be "connected" to another part, this includes not only "directly connected" or "physically connected," but also "electrically connected" with another element intervening therebetween. In this disclosure, the terms "transmit," "receive," and "communicate" encompass both direct and indirect communication. Furthermore, when a part is said to "include" or "comprise" a component, this does not exclude other components, but rather includes other components, unless specifically stated otherwise.

[0031] Throughout this disclosure, unless specifically stated otherwise, "or" is inclusive and not exclusive. Thus, unless expressly indicated otherwise or the context dictates otherwise, "A or B" can refer to "A, B, or both." As used herein, the phrases "at least one of" or "one or more of" can mean that different combinations of one or more of the listed items can be used, or that only any one of the listed items is required. For example, "at least one of A, B, and / or C" can include any of the following combinations: A, B, C, A and B, A and C, B and C, or A and B and C. As used herein, the expression "at least one of A, B, or C" can refer to "A," "B," "C," "A and B," "A and C," "B and C," "all of A, B, and C," or variations thereof.

[0032] In one embodiment of the present disclosure, "connection relationship" may include the meaning of "connection relationship," "inclusion relationship," "attachment relationship," or "matching relationship." For example, "connected" may include the meaning of "connected," "inclusion," "attachment," or "matched." In one embodiment of the present disclosure, "connection" may include the meaning of data communication being possible, either wired or wireless. For example, "A and B are connected" may include the meaning that A and B are capable of data communication, i.e., can transmit and receive data with each other.

[0033] In the present disclosure, Stream Control Transmission Protocol (SCTP) is a part of the Internet protocol, and may be a protocol that provides reliable and message-oriented communication by combining the functions of Transmission Control Protocol (TCP) and User Datagram Protocol (UDP).

[0034] In this disclosure, the term "SCTP association" may refer to a connection between a client and a server that enables communication using SCTP. For example, if there is an SCTP connection between a client and an entity, the client and the entity can communicate and exchange data via SCTP.

[0035] The term "session" in this disclosure refers to a logical grouping of connections or interactions, and may be used to track and maintain interactions between clients and network entities.

[0036] In this disclosure, the term "migration" may refer to the transfer of an SCTP connection between a client and an entity to an SCTP connection between the client and another entity. Furthermore, the term "migration" may be used interchangeably with or in conjunction with the terms "transfer," "migration," and "transition."

[0037] In one embodiment of the present disclosure, the term "transfer" may include moving, copying, duplicating, or synchronizing information to be transferred contained in any logical or physical space to any other space. In one embodiment of the present disclosure, the term "transfer" may include causing information to be transferred (e.g., session information) contained, stored, configured, or set in space A (or entity A, device A, or module A) to be contained, stored, configured, or set in space B (or entity B, device B, or module B). In one embodiment of the present disclosure, "transfer" may include causing information to be transferred contained, stored, configured, or set in space A (or entity A, device A, or module A) to be contained, stored, configured, or set in space B (or entity B, device B, or module B), and removing, deleting, releasing, or deactivating the information to be transferred in space A (or entity A, device A, or module A).

[0038] In one embodiment of the present disclosure, “scale-out for an entity” and “scaling-out for an entity” may mean adding the entity within a server. In one embodiment of the present disclosure, “scale-out for an entity” and “scaling-out for an entity” may include transferring at least some of the information contained in one entity to another entity(ies) (e.g., a newly added entity).

[0039] In one embodiment of the present disclosure, "scale-in for an entity" and "scaling-in for an entity" may include removing, releasing, or deactivating the entity from a server. In one embodiment of the present disclosure, "scale-in for an entity" and "scaling-in for an entity" may include transferring at least some of the information contained in one entity to another entity(ies) (e.g., pre-existing entity(ies)).

[0040] The term "providing a service" in this disclosure may mean that an entity performs tasks (or operations) requested by a client, such as data processing, information retrieval, or transaction processing. By providing a service by performing operations requested by SCTP-connected clients, the entity may mean providing high-performance services to clients via a stable and efficient network protocol.

[0041] In one embodiment of the present disclosure, “A performing action B” may include “A directly performing action B” or “A controlling C to perform action B.” In one embodiment of the present disclosure, “A controlling action B” may include “A directly performing action B” or “A controlling C to perform action B.”

[0042] In one embodiment of the present disclosure, "path" or "interface" may include the meaning of a module (e.g., a software module, a hardware module) that enables data transmission and reception. In one embodiment of the present disclosure, "path" or "interface" may include the meaning of a logical or physical connection relationship. In one embodiment of the present disclosure, "path" or "interface" may include the meaning of a data transmission and reception path. In one embodiment of the present disclosure, "establishing an interface (or path) between A and B" may include the meaning of establishing a configuration that enables A and B to transmit and receive data with each other and process the received data.

[0043] FIG. 1 illustrates a block diagram of a system (10) including a virtualized central unit-control plane (100) according to one embodiment of the present disclosure.

[0044] Referring to FIG. 1, a virtualized Central Unit-Control Plane (vCU-CP) (100) can communicate with one or more clients (11, 12, 13, 14, 15) through a router (16) within a virtualized Radio Access Network (vRAN) system (10).

[0045] 5G(5 thIn a Generation (RAN) Radio Access Network (R&A) system, control signal processing and data signal processing for user data transmission and reception processing can be performed in a CU or a Distributed Unit (DU). The CU can perform control functions previously handled by a base station. For example, the CU can perform function(s) of some layer(s) of network protocol layers (e.g., RRC (Radio Resource Control) layer and / or PDCP (Packet Data Convergence Protocol) layer). The CU can perform functions such as processing various control messages for connection control between a base station and a user terminal (e.g., User Equipment (UE)) and handover between terminals, connecting between two clients to transmit data from one client to another and transmitting a response from one client to another, setting QoS (Quality of Service), reordering packets, etc., and security / authentication-related functions.

[0046] A DU may be an entity that performs the functions of some layers among the protocol layers of the network, excluding some layers performed by the CU. For example, a DU may perform network functions (e.g., baseband functions) of the RLC (Radio Link Control) layer, the MAC (Medium Access Control) layer, or the PHY (Physical) layer, but is not limited thereto. For example, a DU may perform a buffer function, a radio resource scheduling function, a data reprocessing function, a radio signal resource allocation function, or a transmission scheduling function. An RU may convert an analog signal received from a client (e.g., a UE) into a digital signal and transmit the converted digital signal to the DU.

[0047] In the vRAN system (10), CUs and / or DUs may be virtualized. For example, DUs and CUs may be virtualized based on software running on one or more processor(s) (or server(s)) within a general-purpose server, and may be configured as vDUs (virtualized DUs) and vCUs (virtualized CUs), respectively. The vRAN system can be built through software installation / removal / update on a general-purpose server without dependency on a specific network equipment manufacturer (or vendor). Therefore, the vRAN system has high equipment compatibility. In addition, since the vRAN system is a cloud-native based system, it has scalability and flexibility, and thus capital expenditures (CAPEX) and operating expenditures (OPEX) can also be reduced.

[0048] The vRAN system may include a vCU-CP (100), an evolved Node B (eNB) (12), a Next-Generation Node B (gNB) (13), a virtualized Core (14), a virtualized Centralized Unit-User Plane (vCU-UP) (15), and a router (16). The vCU-CP (100) may control a connection between a base station (e.g., an eNB (12) or a gNB (13)) and a UE (not shown), and may process control messages for controlling handover between base stations. The vCU-CP (100) may transmit user data to the virtualized Core (14) or receive response data from the virtualized Core (14).

[0049] The vDU (11) can allocate wireless signal resources and manage transmission scheduling. For example, the vDU (11) can perform functions such as wireless resource management, user authentication, and data transmission. The vDU (11) can perform data processing to distribute the functions of a wireless base station. In one embodiment, the vDU (11) can communicate with the vCU-CP (100) based on the F1 interface standard.

[0050] eNB(12) is 4G(4 thThe eNB (12) and the gNB (13) may be base stations on a 5G NR (New Radio) communication system. The eNB (12) and the gNB (13) may propagate wireless signals and communicate with one or more UEs. The eNB (12) and the gNB (13) may communicate with other base stations via the vCU-CP (100). In one embodiment, the eNB (12) and the gNB (13) may communicate with the vCU-CP (100) based on X2 and Xn interface specifications, respectively. The virtualization core (14) may manage authentication of a user terminal (e.g., UE) and / or a session of a user terminal. The virtualization core (14) may process statistics and charging of user data. In one embodiment, the virtualized core (14) may be a communication system having a large capacity and ultra-high speed data transmission function, located at the backend of a base station (e.g., an eNB (12) and a gNB (13)). In one embodiment, the virtualized core (14) may be a virtualized core network to which base stations are connected or a network function (or an entity performing a network function) within the virtualized core network. For example, the virtualized core (14) may be an entity performing an access and mobility management function (AMF) and / or a session management function (SMF). In one embodiment, the virtualized core (14) may communicate with the vCU-CP (100) based on the NG interface standard.

[0051] The vCU-UP (15) may be a virtualized entity of the user plane of a network (e.g., a vRAN system (10) or a vCU). The vCU-UP (15) may receive user data, process the received user data, and transmit the processed data to the user. In one embodiment, the vCU-UP (15) may communicate with the vCU-CP (100) based on the E1 interface standard.

[0052] The router (16) can perform an IP (Internet Protocol) routing function between the clients (11 to 15) and the vCU-CP (100). The router (16) can determine which of the activated one or more connection management entities (111, 112, ..., 11N; N is a natural number) connection management entity to which traffic or IP (Internet Protocol) packets transmitted from the clients (11 to 15) should be transmitted, and can transmit the traffic or packets to the corresponding connection management entity based on the determination. In one embodiment, the router (16) can distribute packets based on a round robin or hashing algorithm, etc.

[0053] vCU-CP (100) may include one or more connection management entities (111 to 11N), one or more call processing entities (121, 122, 123, …, 12M; M is a natural number), an OAM (Operation Administration Maintenance) entity (130), and a leader selection entity (140).

[0054] Connection management entities (111 to 11N) can distribute requests from clients (11 to 15) received via the router (16) to call processing entities (121 to 12M). The vCU-CP (100) can be connected to external nodes (or entities) (e.g., clients (11 to 15)) based on SCTP. The connection management entities (111 to 11N) can manage SCTP-based communication connections of the vCU-CP (100). In one embodiment, the connection management entities (111 to 11N) can act as a load balancer of a layer 4 (L4) based on the SCTP protocol and / or an NR load balancer of a layer 7 (L7) based on NR interface messages.

[0055] Call processing entities (121 to 12M) can process requests from clients (11 to 15) and transmit processing responses (or processing results) to the clients (11 to 15) via the corresponding connection management entity. For example, call processing entities (121 to 12M) can process requests generated from user terminals connected to the clients (11 to 15). Various procedures can be defined for each of various services between the user terminal and the network. Call processing can include processing(s) for providing services to the user terminal according to the corresponding procedure. For example, when a user terminal requests access to a specific website, the call processing entity that receives the request can process the request (or call) by allocating wireless resources, authenticating the user terminal, and securing a data downlink path.

[0056] The OAM entity (130) may perform functions for maintaining, repairing, and managing the vCU-CP (100). For example, the OAM entity (130) may manage the lifecycle of each entity within the vCU-CP (100). The OAM entity (130) may detect events for connection management entities and provide status information indicating the detected events to the entities within the vCU-CP (100). In one embodiment, the OAM entity (130) may receive requests for cell increase or decrease from clients (11 to 15), and may determine, based on such requests, that a scaling-in or scaling-out event for a connection management entity should be performed. In one embodiment, the OAM entity (130) may detect that a failure has occurred for a connection management entity. In one embodiment, the OAM entity (130) may be located outside of the vCU-CP (100).

[0057] The leader selection entity (140) can select any one of the connection management entities (111 to 11N) as a leader. The leader selection entity (140) can store the leader selection result. In one embodiment, the leader selection entity (140) can select any one of the connection management entities (111 to 11N) as a leader when the vCU-CP (100) is configured (or restarted). In one embodiment, the leader selection entity (140) can re-select any one of the connection management entities (111 to 11N) as a new leader in response to a re-selection request from the OAM entity (130), status information from the OAM entity (130), or requests from other entities within the vCU-CP (100). The leader selection entity (140) receives status information from the OAM entity (130) and may select a new leader or postpone the selection of a new leader based on the received status information. In one embodiment, the leader selection entity (140) may be located outside of the vCU-CP (100).

[0058] In one embodiment, the leader selection entity (140) may randomly or rule-based select one of the connection management entities as the leader. For example, the leader selection entity (140) may select the entity with the largest ID (e.g., the largest ID value) among the connection management entities as the new leader. Alternatively or additionally, the leader selection entity (140) may select the entity with the smallest ID (e.g., the smallest ID value) among the connection management entities as the new leader.

[0059] In one embodiment, one or more entities (e.g., one or more of entities (111 to 11N, 121 to 12M, 130, 140)) within vCU-CP (100) may be implemented as a processing pod, a component module, an arbitrary processing operation unit, a deployment unit performing any processing, or software, etc. For example, vCU-CP (100) may be implemented based on Kubernetes (k8s). Each entity within vCU-CP (100) may be configured as a pod including one or more containers. Each container within each pod may be configured as one or more processes (or operations).

[0060] vCU-CP (100) can be connected to external nodes (or entities) (e.g., clients (11 to 15)) based on SCTP. SCTP is a message-based transport layer protocol, and can be a protocol that combines the message streaming feature of UDP and the connection-oriented and reliable providing feature of TCP. SCTP connections of vCU-CP (100) can be managed by connection management entities (111 to 11N).

[0061] In one embodiment, the vCU-CP (100) may include one active connection management entity. To support redundancy, the vCU-CP (100) may further include a standby connection management entity, and the standby connection management entity may use hardware standby resources within the vCU-CP (100). Even if the number of users of the vCU-CP (100) decreases, the number of connection management entities may not decrease, and thus, idle resources occupied by the vCU-CP (100) may increase. Even if the number of users of the vCU-CP (100) increases, the number of connection management entities may not increase. Additionally, after all connections between the vCU-CP (100) and external nodes are released for additional resource allocation, the vCU-CP (100) may be reconfigured (e.g., software for the vCU-CP (100) may be redistributed and reinstalled), and the reconfigured vCU-CP (100) may be reconnected to the external nodes.

[0062] In one embodiment, the vCU-CP (100) may include multiple active connection management entities and may not include a standby connection management entity. The multiple active connection management entities may be scalable. For example, as the number of users increases, the number of connection management entities may increase, and as the number of users decreases, the number of connection management entities may decrease. Accordingly, the entire server on which the vCU-CP (100) is configured may be scaled in or out, thereby ensuring the stability of the vRAN system (10) and enabling efficient use of hardware resources. In addition, even if a failure occurs in a connection management entity, other connection management entity(ies) may replace the failed entity, thereby minimizing the impact on user terminals due to the failure.

[0063] In embodiments where vCU-CP (100) includes multiple active connection management entities, when distributing SCTP connections among the connection management entities, sessions of the SCTP connections may be allocated to only some entities, resulting in traffic concentration. Therefore, a leader connection management entity may be selected to monitor and reallocate imbalances among sessions of the connection management entities. The leader connection management entity may manage session allocation for the remaining follower connection management entities and share session information with each connection management entity.

[0064] One or more activated connection management entities (111 to 11N) on a vCU-CP (100) may change their operational status in response to a failure event or a scaling event due to cell increase or decrease. In the following, embodiments in which session information is shared among a leader connection management entity, follower connection management entities, and call processing entities, and embodiments in which a scaling-in event or a failure event occurs for a single connection management entity will be described.

[0065] FIGS. 2A and 2B illustrate a scaling-in event of a connection management entity according to one embodiment of the present disclosure.

[0066] Referring to FIGS. 2A and 2B, a scaling-in event may occur in response to a cell reduction (de-scaling) request for a connection management entity (213) of a vCU-CP (200). The vDU (21), the eNB (22), the gNB (23), the virtualization core (24), the vCU-UP (25), and the router (26) may be implemented in a similar manner to the vDU (11), the eNB (12), the gNB (13), the virtualization core (14), the vCU-UP (15), and the router (16) of FIG. 1, respectively, and may operate in a similar manner. The connection management entities (211, 212, 213) may be implemented in a similar manner to the connection management entity (111) of FIG. 1, and may operate in a similar manner. The call processing entities (221, 222, 223, 224) may be implemented in a similar manner to the call processing entity (121) of FIG. 1 and may operate in a similar manner. For convenience of illustration, it will be appreciated that the illustration of the OAM entity and the leader selection entity associated with the vCU-CP (200) has been omitted.

[0067] In one embodiment, the vCU-CP (200) may additionally include load balancer entities (231, 232). The load balancer entity (231) may function as a load balancer of Layer 4 (L4) based on the SCTP protocol. The load balancer entities (231, 232) may distribute connections and / or traffic between the vCU-CP (200) and clients (21 to 25). For example, the load balancer entity (231) may distribute connection load and / or traffic input to connection management entities (211, 212, 213) within the vCU-CP (200) via a router (26). The load balancer entity (231) monitors the connection management entities (211, 212, 213), rebalances traffic between the connection management entities (211, 212, 213), and transfers traffic of a failed entity to other connection management entities. Depending on the operation of the load balancer entities (231, 232), the connection management entity (211) may process traffic (211-1), the connection management entity (212) may process traffic (212-1), and the connection management entity (213) may process traffic (213-1).

[0068] The load balancer entity (231) can receive SCTP packets from clients (21 to 25) and process the received SCTP packets. The load balancer entity (231) can select an appropriate call processing entity among the call processing entities (221, 222, 223, 224) for the received SCTP packets. The load balancer entity (231) can perform Network Address Translation (NAT) processing on the SCTP packets and transmit the SCTP packets processed by the selected call processing entity through the connection management entities (211, 212, 213). The load balancer entity (231) can forward the SCTP packets to the connection management entities (211, 212, 213) based on a least connection or round robin algorithm.

[0069] In one embodiment, connection management entities (211, 212, 213) may receive SCTP packets from load balancer entities (231, 232). Connection management entities (211, 212, 213) may decapsulate the received SCTP packets and forward the decapsulated SCTP packets to a corresponding call processing entity based on the ID of the NR AP (Application Protocol) message.

[0070] In one embodiment, vCU-CP (200) may not include load balancer entities (231, 232). In such an embodiment, connection management entities (211, 212, 213) may perform the functions of load balancer entities (231, 232).

[0071] In the embodiment of FIG. 2A, clients (21, 22, 23, 24, 25) may request cell reduction to vCU-CP (200). For example, based on a decrease in the number of users accessing vCU-CP (200), at least one of the clients (21 to 25) may request vCU-CP (200) to reduce the number of cells managed by vCU-CP (200) (or the processing capacity of vCU-CP (200)).

[0072] In response to a cell reduction request from clients (21 to 25), the vCU-CP (200) may determine to perform scaling-in for a connection management entity (213). For example, an OAM entity of the vCU-CP (200) (or an OAM entity external to the vCU-CP (200)) may determine to perform scaling-in to remove at least one connection management entity. As scaling-in is performed, the processing capacity of the vCU-CP (200) may be reduced.

[0073] In one embodiment, the target connection management entity for scaling-in may be selected randomly or based on preset rules. For example, the entity with the largest ID value or the entity with the smallest ID value among the connection management entities (211, 212, 213) may be selected as the target for scaling-in. For example, the entity that handles the least traffic or the entity that handles the most traffic among the connection management entities (211, 212, 213) may be selected as the target for scaling-in.

[0074] In one embodiment, vCU-CP (200) may operate based on Kubernetes. The auto scaling function provided by Kubernetes may be used to perform scaling-in for a single connection management entity.

[0075] In the embodiment of FIG. 2A, a connection management entity (213) may be selected as a target of a scaling-in event. An OAM entity of a vCU-CP (200) may detect a scaling-in event for the connection management entity (213) and transmit state information indicating that the connection management entity (213) is a target of the scaling-in event to entities within the vCU-CP (200) (e.g., entities (231, 232, 211, 212, 213, 221, 222, 223, 224)). For example, a request for scaling-in may be received from outside the vCU-CP (200) to the OAM entity, and the OAM entity may generate state information indicating a scaling-in event based on the received request. In response to the received status information, the call processing entities (221, 222, 223, 224) may withhold transmission of call processing responses that are to be transmitted to the connection management entity (213). In response to the received status information, the connection management entity (213) may initiate a termination procedure for the SCTP connection processing related to the 5G call message assigned to it. In response to the received status information, traffic (213-1) being processed by the connection management entity (213) may be redistributed to the connection management entities (211, 212). For example, sessions of SCTP connections managed by the connection management entity (213) may be reallocated to the connection management entities (211, 212). Session information regarding sessions of the connection management entity (213) may be transferred to the connection management entities (211, 212). After transferring its session information, the connection management entity (213) can complete the termination procedure.

[0076] In one embodiment, the transferred session information may include connection information between the vCU-CP (200) and external network nodes (e.g., vDU (21), eNB (22), gNB (23), virtualization core (24), and vCU-UP (25)). For example, the session information may include at least one of the following: an ID of a connection management entity responsible for (or managing) SCTP connections for each entry (or external peer), a gNB ID of the vCU-CP (200), an NR interface type of each session (e.g., F1, E1, NG, X2, or Xn interface), the number of SCTP connections per NR interface, or NAT information of each session. The NAT information of each session may include at least one of the following: a source address, a destination address, a source port, a destination port, or a protocol type. Based on the NAT information of the session, the network address used within the connection management entities (or used within the vCU-CP (200)) can be converted to a network address for the external node.

[0077] Based on the session information transferred from the connection management entity (213), the connection management entities (211, 212) can perform SCTP reconnection. In one embodiment, the connection management entities (211, 212) can perform SCTP restart based on the session information transferred from the connection management entity (213). After the SCTP reconnection of the connection management entities (211, 212) is completed, the connection management entity (213) can be removed (or deactivated, or released) as illustrated in FIG. 2B. The traffic (213-1) processed by the connection management entity (213) in FIG. 2A can be redistributed to the connection management entity (211) and the connection management entity (212). For example, a portion (213-11) of traffic (213-1) processed by connection management entity (213) may be distributed to connection management entity (211). A portion (213-12) of traffic (213-1) processed by connection management entity (213) may be distributed to connection management entity (212).

[0078] In one embodiment, the reallocation of session information (or traffic, or SCTP connections) of a connection management entity (213) may be performed by an entity selected as a leader among the connection management entities (211, 212). The leader connection management entity may be selected as a leader before the occurrence of a scaling-in event, or may be newly selected as a leader in response to the occurrence of a scaling-in event. The leader connection management entity may always or as needed store the latest session information of each connection management entity in an internal storage of the entity or an external storage of the entity. Based on the stored session information, the leader connection management entity may reallocate the session information of the connection management entity to be scaled-in to the remaining connection management entities. In one embodiment, a new leader connection management entity may be selected for the scaling-in, and the previous leader connection management entity may forward the stored latest session information to the new leader connection management entity.

[0079] Alternatively or additionally, the load balancer entities (231, 232) may fail to distribute SCTP packets evenly to the connection management entities (211, 212, 213). For example, the load balancer entities (231, 232) may forward more SCTP packets to a particular connection management entity. In the embodiment of FIG. 2A, the traffic (211-1) processed by the connection management entity (211) may be greater than the traffic (212-1) processed by the connection management entity (212) and the traffic (213-1) processed by the connection management entity (213). For example, the number of sessions handled by a connection management entity (211) may be relatively greater than the number of sessions handled by a connection management entity (212) and the number of sessions handled by a connection management entity (213). Accordingly, there may be a need to rebalance sessions among the connection management entities (211, 212, 213). Based on this need, the OAM entity of the vCU-CP (200) may request a redistribution of sessions to a leader connection management entity. In response to the request from the OAM entity, the leader connection management entity may decide to reallocate session information of a connection management entity and reallocate at least a portion of the session information of the connection management entity to other connection management entity(ies). At least a portion of the reallocated session information may be transferred to the corresponding connection management entity(ies). Accordingly, sessions among the connection management entities may be rebalanced. In one embodiment, session rebalancing between connection management entities may be performed periodically.

[0080] Alternatively or additionally, the vCU-CP (200) may further include a scaling agent (not shown) that manages scaling of the connection management entities (211, 212, 213). The scaling agent may decide to perform scaling-in or scaling-out of the connection management entities based on cell expansion / reduction requests input to the vCU-CP (200), an increase / decrease in user calls input to the vCU-CP (200), an increase / decrease in the number of clients connected to the vCU-CP (200), and / or an increase / decrease in the total traffic volume of the connection management entities. The scaling agent may request the leader connection management entity to perform scaling-in or scaling-out for a specific connection management entity.

[0081] In one embodiment, to add a new connection management entity to vCU-CP (200), the scaling agent may decide to scale out for the new connection management entity. The scaling out may include establishing a new connection management entity, reallocating session information of at least one of the existing connection management entities (211, 212, 213) to the new connection management entity, and transferring the reallocated session information to the new connection management entity. To perform the scaling out, the scaling agent may request the leader connection management entity to perform the scaling out for the new connection management entity. In response to a scaling-out request, the leader connection management entity can reallocate session information of at least one of the existing connection management entities (211, 212, 213) to a new connection management entity and provide the reallocated session information to the existing connection management entities (211, 212, 213) and the new connection management entity. Based on the reallocated session information, the connection management entities can perform an SCTP reconnection (or a new connection).

[0082] In one embodiment, to remove a connection management entity from a vCU-CP (200), the scaling agent may select any one of the connection management entities (211, 212, 213) as a target for scaling-in. The scaling agent may select the target for scaling-in randomly or based on a rule. For example, the scaling agent may store information indicating which connection management entity among the connection management entities is a leader connection management entity. The scaling agent may select an entity among the connection management entities that is not a leader connection management entity, for example, any one of the follower connection management entities, as a target for scaling-in. In other words, the scaling agent may select a target for scaling-in from among the connection management entities excluding the leader connection management entity. For example, the scaling agent can randomly select one of the follower connection management entities, select the entity with the largest ID value among the follower connection management entities, or select the entity with the lowest ID value among the follower connection management entities. To perform the scale-in, the scaling agent can request that the connection management entity selected as the leader connection management entity perform the scale-in. In response to the scale-in request, the leader connection management entity can reallocate the session information of the selected connection management entity to the existing connection management entities that were not selected, and provide the reallocated session information to the existing connection management entities that were not selected. Based on the reallocated session information, the connection management entities can perform an SCTP reconnection (or a new connection).

[0083] FIGS. 3A and 3B illustrate a failure event of a connection management entity according to one embodiment of the present disclosure.

[0084] Referring to FIGS. 3A and 3B , a failure event may occur for a connection management entity (313) of a vCU-CP (300). The vDU (31), the eNB (32), the gNB (33), the virtualization core (34), the vCU-UP (35), and the router (36) may be implemented in a similar manner to the vDU (11), the eNB (12), the gNB (13), the virtualization core (14), the vCU-UP (15), and the router (16) of FIG. 1 , respectively, and may operate in a similar manner. The connection management entities (311, 312, 313) may be implemented in a similar manner to the connection management entity (111) of FIG. 1 , and may operate in a similar manner. The call processing entities (321, 322, 323, 324) may be implemented in a similar manner to the call processing entity (121) of FIG. 1 and may operate in a similar manner. The load balancer entities (331, 332) may be implemented in a similar manner to the load balancer entity (231) of FIG. 2 and may operate in a similar manner. Depending on the operation of the load balancer entities (331, 332), the connection management entity (311) may process traffic (311-1), the connection management entity (312) may process traffic (312-1), and the connection management entity (313) may process traffic (313-1). For the sake of illustration, it will be appreciated that the illustration of the OAM entity and the leader election entity for the vCU-CP (300) has been omitted.

[0085] In the embodiment of FIG. 3A, a failure may occur in the connection management entity (313). Accordingly, the connection management entity (313) may be abruptly terminated, and SCTP connections between the connection management entity (313) and external nodes may be released. The OAM entity of the vCU-CP (200) may constantly, periodically, or aperiodically monitor the status of the connection management entities. Through monitoring, the OAM entity may detect that a failure has occurred in the connection management entity (313). Based on detecting a failure in the connection management entity (313), the OAM entity may generate status information indicating that a failure has occurred in the connection management entity (313). The OAM entity can transmit the generated state information to entities (331, 332, 311, 312, 321, 322, 323, 324) within vCU-CP.

[0086] In response to the received status information, the call processing entities (321, 322, 323, 324) may withhold transmission of a call processing response that is to be transmitted to the connection management entity (313). In response to the received status information, traffic (313-1) being processed by the connection management entity (313) may be redistributed to the connection management entities (311, 312). For example, sessions of SCTP connections managed by the connection management entity (213) may be reallocated to the connection management entities (311, 312). Session information regarding sessions of the connection management entity (313) may be transferred to the connection management entities (311, 312). The session information may include at least one of the following: an ID of a connection management entity responsible for (or managing) the SCTP connection for each entry (or external peer), a gNB ID of the vCU-CP (300), an NR interface type of each session (e.g., F1, E1, NG, X2, or Xn interface), the number of SCTP connections per NR interface, or NAT information of each session. The NAT information of each session may include at least one of the following: a source address, a destination address, a source port, a destination port, or a protocol type. Based on the NAT information of the session, a network address used within the connection management entities (or used within the vCU-CP (300)) may be converted to a network address for an external node.

[0087] Based on the reallocated session information, the connection management entities (311, 312) can perform SCTP reconnection. In one embodiment, the connection management entities (311, 312) can perform SCTP restart based on the reallocated session information from the connection management entity (313). After the SCTP reconnection of the connection management entities (311, 312) is completed, the traffic (313-1) processed by the connection management entity (313) in FIG. 3A can be redistributed to the connection management entity (311) and the connection management entity (312). For example, as illustrated in FIG. 3B, a portion (313-11) of the traffic (313-1) processed by the connection management entity (313) can be distributed to the connection management entity (311). A portion (313-12) of the traffic (313-1) being processed by the connection management entity (313) may be distributed to the connection management entity (312).

[0088] In one embodiment, the reallocation of session information (or traffic, or SCTP connections) of a connection management entity (313) may be performed by an entity selected as a leader among the connection management entities (311, 312). The leader connection management entity may be selected as a leader before a failure event occurs, or may be newly selected as a leader in response to the failure event. The leader connection management entity may always or as needed store the latest session information of each connection management entity in an internal storage of the entity or an external storage of the entity. Based on the stored session information, the leader connection management entity may reallocate the session information of the failed connection management entity to the remaining connection management entities. In one embodiment, a new leader connection management entity may be selected due to a failure event, and the remaining connection management entities may provide their session information to the new leader connection management entity. The new leader connection management entity can determine the session information of the failed connection management entity based on the session information of the remaining connection management entities. The new leader connection management entity can reallocate the session information of the failed connection management entity to the remaining connection management entities.

[0089] FIG. 4 illustrates a method (400) for at least partially reallocating session information between entities within a vCU-CP according to one embodiment of the present disclosure.

[0090] In the embodiment of FIG. 4, the OAM entity (41) may be implemented in a similar manner to the OAM entity (130) of FIG. 1 and may operate in a similar manner. The connection management entities (42, 43, 44) may be implemented in a similar manner to the connection management entity (111) of FIG. 1 and may operate in a similar manner. The call processing entity (45) may be implemented in a similar manner to the call processing entity (121) of FIG. 1 and may operate in a similar manner. The leader selection entity (46) may be implemented in a similar manner to the leader selection entity (140) of FIG. 1 and may operate in a similar manner.

[0091] In the embodiment of FIG. 4, the connection management entity (42) may be a leader of the connection management entities (42, 43, 44). The connection management entities (43, 44) may be follower connection management entities. In the embodiment of FIG. 4, a scaling-in event may occur for the connection management entity (44). Referring to FIG. 4, through the method (400), the connection management entity (42) may reallocate session information of the connection management entity (44) to the connection management entity (42) and the connection management entity (43). Through the method (400), the connection management entity (42) may share the reallocated session information with the connection management entities (43, 44). For example, through method (400), session information of connection management entity (213) of FIG. 2A may be redistributed to connection management entities (211, 212). Method (400) may include steps (401 to 412). Method (400) is not limited to that illustrated in FIG. 4, and in one or more embodiments, method (400) may further include steps not illustrated in FIG. 4, some of the steps of FIG. 4 may be omitted from method (400), or the order of some of the steps of FIG. 4 may be changed.

[0092] In step (401), the OAM entity (41) may transmit status information to entities (42, 43, 44, 45, 46) within the vCU-CP. The status information may indicate the type of event that occurred within the vCU-CP and the target of the event. The type of event indicated by the status information may include an increase (e.g., scaling out of entities), a decrease (e.g., scaling in of entities), or a failure of one or more entities. In the embodiment of FIG. 4, the status information may indicate a scaling in for the connection management entity (44).

[0093] In the embodiment of FIG. 4, the leader selection entity (46) can identify the target of the event indicated by the state information based on the received state information. The leader selection entity (46) can store the IDs of the connection management entities within the current vCU-CP and information indicating which entity among the connection management entities is the leader. The leader selection entity (46) can identify that the target of the event indicated by the state information is a follower (e.g., the connection management entity (44)) and not a leader (e.g., the connection management entity (42)). Based on identifying that the target of the event indicated by the state information is not the leader of the connection management entities, the leader selection entity (46) can suspend leader re-election.

[0094] In step (402), the connection management entity (44) may initiate a termination procedure based on status information received from the OAM entity (41). In step (403), the connection management entity (44) may transmit a termination notification to the connection management entity (42) indicating that it is about to be terminated.

[0095] In one embodiment, the termination procedure may include starting a termination timer, notifying the connection management entity (42) that it is about to be terminated, receiving a response to the notification from the connection management entity (42), and terminating its operations (or those of its internal containers) based on the received response. For example, based on state information indicating scaling-in for the connection management entity (44), the connection management entity (44) may identify (or determine) that it is about to be terminated, start a termination timer, and notify the connection management entity (42) that it is about to be terminated. Until the termination timer expires and / or a termination notification response is received from the connection management entity (42), the connection management entity (44) may maintain the SCTP connections managed by it without completing the termination procedure. The termination notification message may be a message requesting the leader connection management entity to transfer its sessions to other connection management entities. In one embodiment, the termination procedure may be the graceful termination procedure provided by Kubernetes.

[0096] In one embodiment, the termination timer may expire after a sufficient amount of time for session information for the connection management entity (44) to be reassigned to other connection management entities (e.g., entities (42, 44)). For example, the termination timer may be set to 30 seconds, 60 seconds, 90 seconds, or any other suitable time. The termination timer may be set by the OAM entity (41) or may have been preset when the connection management entity (44) was established. In one embodiment, the termination procedure may not include starting the termination timer.

[0097] In step (404), based on the status information received from the OAM entity (41), the call processing entity (45) may wait for transmission of a processing response. For example, the call processing entity (45) may withhold transmission of a call processing response that is to be transmitted to a target of an event indicated in the received status information. In the embodiment of FIG. 4, the status information may indicate scaling-in to the connection management entity (44), and based on the status information, the call processing entity (45) may withhold transmission of the processing response(s) that are to be transmitted to the connection management entity (44).

[0098] In step (405), based on the state information received from the OAM entity (41), the connection management entity (42) can reallocate session information for the connection management entity (44). The connection management entity (42) can identify a target of an event indicated in the received state information. Based on the fact that the target of the identified event is the connection management entity (44), the connection management entity (42) can reallocate session information for the connection management entity (44) to at least some of other connection management entities (e.g., connection management entities (42, 43)) other than the connection management entity (44). For example, the connection management entity (42) can reallocate session information for a first connection among the SCTP connections managed by the connection management entity (44) to the connection management entity (43) and can reallocate session information for a second connection among the SCTP connections to the connection management entity (42).

[0099] In one embodiment, the connection management entity (42) may include a session table that stores session information of some or all of the connection management entities within the vCU. Alternatively or additionally, the connection management entity (42) may manage (or access) a session table (or database) stored in an external storage device. Based on the session information of the connection management entities stored in the session table, the connection management entity (42) may reallocate the session information for the connection management entity (44) to other connection management entities other than the connection management entity (44). For example, the connection management entity (42) may reallocate the session information for the connection management entity (44) to other connection management entities other than the connection management entity (44) taking into account the traffic balance between the connection management entities or the number of SCTP connections assigned to each of the connection management entities.

[0100] In step (406), the connection management entity (42) can transmit the session information reallocated in step (405) to the connection management entity (43). For example, based on the reallocation of session information for a first connection among one or more SCTP connections managed by the connection management entity (44) to the connection management entity (43), the connection management entity (42) can transmit session information for the first connection to the connection management entity (43).

[0101] In step (407-1), the connection management entity (42) can perform SCTP reconnection based on the reassigned session information. In step (407-2), the connection management entity (43) can perform SCTP reconnection based on the reassigned session information. For example, the connection management entity (42) can perform SCTP reconnection based on the session information reassigned to the connection management entity (42) in step (405). The connection management entity (43) can perform SCTP reconnection based on the received reassigned session information. For example, the connection management entity (42) and the connection management entity (43) can initiate connections with endpoints of the SCTP connection(s) included in their reassigned session information based on the reassigned session information. In one embodiment, the connection management entity (42) and the connection management entity (43) may perform a restart mechanism supported by SCTP based on the reallocated session information.

[0102] In step (408), if SCTP reconnection is completed, the connection management entity (43) may transmit reconnection completion information indicating that SCTP reconnection is completed to the connection management entity (42). For example, the reconnection completion information may indicate that the connection management entity (43) has established SCTP connections based on reallocated session information.

[0103] In step (409), the connection management entity (42) may transmit a response to the termination notification received in step (403) to the connection management entity (44). The connection management entity (42) may identify (or determine) that its SCTP reconnection is complete, and may transmit a response to the termination notification to the connection management entity (43) based on the fact that its SCTP reconnection is complete and the receipt of reconnection completion information from the connection management entity (44). For example, the response to the termination notification may indicate that the SCTP connections managed by the connection management entity (44) have been transferred to other connection management entity(ies).

[0104] In step (410), based on the response to the termination notification, the connection management entity (44) may complete the termination procedure. The connection management entity (44) may terminate its own operations (or the operations of its internal containers) after receiving the response to the termination notification. Upon termination of the connection management entity (44), SCTP connections managed by the connection management entity (44) may be released.

[0105] In step (411), the connection management entity (42) may transmit the reallocated session information in step (405) to the call processing entity (45). In response to receiving the reallocated session information, the call processing entity (45) may restart transmitting the processing response.

[0106] In step (412), the call processing entity (45) may transmit the pending processing response to the corresponding connection management entity. For example, if session information for a first SCTP connection among the SCTP connections managed by the connection management entity (44) is reassigned to the connection management entity (43), the call processing entity (45) may transmit the processing response(s) that should be transmitted to the endpoint associated with the first SCTP connection among the pending processing responses to the connection management entity (43). Similarly, if session information for a second SCTP connection among the SCTP connections managed by the connection management entity (44) is reassigned to the connection management entity (43), the call processing entity (45) may transmit the processing response(s) that should be transmitted to the endpoint associated with the second SCTP connection among the pending processing responses to the connection management entity (44).

[0107] In the method (400) of FIG. 4, the connection management entity (44), which is the target of the scaling-in event, does not immediately terminate upon receiving state information. Instead, the connection management entity (44) may wait (or hold) its termination until the SCTP connections managed by the connection management entity (44) are redistributed (or transferred) to other connection management entities. Accordingly, the abrupt closing of the SCTP connections managed by the connection management entity (44) can be avoided.

[0108] FIG. 5 illustrates a method (500) for at least partially reallocating session information between entities within a vCU-CP according to one embodiment of the present disclosure.

[0109] In the embodiment of FIG. 5, the OAM entity (51) may be implemented in a similar manner to the OAM entity (130) of FIG. 1 and may operate in a similar manner. The connection management entities (52, 53, 54) may be implemented in a similar manner to the connection management entity (111) of FIG. 1 and may operate in a similar manner. The call processing entity (55) may be implemented in a similar manner to the call processing entity (121) of FIG. 1 and may operate in a similar manner. The leader selection entity (56) may be implemented in a similar manner to the leader selection entity (140) of FIG. 1 and may operate in a similar manner.

[0110] In the embodiment of FIG. 5, the connection management entity (52) may be the current leader of the connection management entities (52, 53, 54). The connection management entities (53, 54) may be follower connection management entities. In the embodiment of FIG. 5, a scaling-in event may occur for the connection management entity (52). Referring to FIG. 5, through the method (500), the connection management entity (52), which is the leader connection management entity, may be terminated. Through the method (500), the connection management entity (54) may be elected as the new leader, reallocate session information of the connection management entity (52), and share the reallocated session information with the entities (53, 55). The method (500) may include steps (501 to 518). The method (500) is not limited to that illustrated in FIG. 5, and in one or more embodiments, the method (500) may further include steps not illustrated in FIG. 5, some of the steps in FIG. 5 may be omitted from the method (500), or the order of some of the steps in FIG. 5 may be changed.

[0111] In step (501), the OAM entity (51) may transmit state information to entities (52, 53, 54, 55, 56) within the vCU-CP. In the embodiment of FIG. 5, the state information may indicate scaling-in to the connection management entity (52).

[0112] In step (502), the connection management entity (52) may initiate a termination procedure based on the state information received from the OAM entity (51). The termination procedure may include starting a termination timer, notifying the new leader connection management entity that it is about to be terminated, receiving a response to the notification from the new leader connection management entity, and terminating its operations (or the operations of its internal containers) based on the received response. For example, based on the state information indicating scaling-in for the connection management entity (52), the connection management entity (52) may identify (or determine) that it is about to be terminated and start a termination timer. The connection management entity (52) may notify the new leader connection management entity that it is about to be terminated. Until the termination timer expires and / or a termination notification response is received from the new leader connection management entity, the connection management entity (52) may maintain the SCTP connections managed by it without completing the termination procedure. In one embodiment, the shutdown procedure may be the graceful shutdown procedure provided by Kubernetes.

[0113] In one embodiment, the termination timer may expire after a sufficient amount of time for session information for the connection management entity (52) to be reassigned to other connection management entities (e.g., entities (53, 54)). For example, the termination timer may be set to 30 seconds, 60 seconds, 90 seconds, or any other suitable time. The termination timer may be set by the OAM entity (51) or may have been preset when the connection management entity (52) was established. In one embodiment, the termination procedure may not include starting the termination timer.

[0114] In step (503), based on the status information received from the OAM entity (51), the call processing entity (55) may wait for transmission of a processing response. For example, the call processing entity (55) may withhold transmission of call processing response(s) that are to be transmitted to the connection management entity (52) that is the target of the event indicated in the received status information.

[0115] In step (504), the leader selection entity (56) may re-elect a leader based on the received state information. The leader selection entity (56) may store IDs of connection management entities within the current vCU-CP and information indicating which entity among the connection management entities is the leader. The leader selection entity (56) may identify that the target of the event indicated by the state information is the current leader of the connection management entities (i.e., the connection management entity (52)). Based on identifying that the target of the event indicated by the state information is the leader of the connection management entities, the leader selection entity (56) may decide to re-elect a leader. The leader selection entity (56) may re-elect one of the connection management entities (53, 54) as the new leader. In the embodiment of FIG. 5, the leader selection entity (56) may select the connection management entity (54) as the new leader.

[0116] In one embodiment, the leader selection entity (56) may randomly or rule-based select one of the connection management entities as the leader. For example, the leader selection entity (56) may select the entity with the largest ID (e.g., the largest ID value) among the connection management entities as the new leader. Alternatively, the leader selection entity (56) may select the entity with the smallest ID (e.g., the smallest ID value) among the connection management entities as the new leader.

[0117] In step (505), the leader selection entity (56) may transmit leader re-election information to entities (52, 53, 54, 55) within the vCU-CP. The leader re-election information may indicate that the connection management entity (54) has been selected as the new leader of the connection management entities. The leader re-election information may indicate that the leader of the connection management entities has changed from the connection management entity (52) to the connection management entity (54).

[0118] At step (506), the connection management entity (54) may transition from a follower to a leader based on the received leader re-election information. The connection management entity (54) may initialize at least some of its functions to perform its role as the new leader. The connection management entity (54) may prepare to receive session information from follower connection management entities (52, 53).

[0119] In step (507), the connection management entity (52) may be switched from a leader to a follower based on the received leader re-election information. The connection management entity (52) may prepare to transmit session information to the new leader.

[0120] In step (508), the connection management entity (52) can transmit session information of the connection management entity (52) to a new leader, i.e., the connection management entity (54). In step (509), the connection management entity (53) can transmit session information of the connection management entity (53) to a new leader, i.e., the connection management entity (54).

[0121] In one embodiment, a connection management entity (52) may segment and transmit its session information to a connection management entity (54). The connection management entity (52) may transmit a first portion of its session information during a first time period, and a second portion of its session information during a second time period. For example, the connection management entity (52) may segment and transmit its session information to the connection management entity (54) by NR interface type (e.g., F1, E1, NG, X2, or Xn) and / or endpoint (e.g., gNB (next generation Node B)) ID. The connection management entities may have a packet processing structure per NR interface type and / or endpoint ID. Therefore, by segmenting and transmitting and / or receiving session information per NR interface type and / or endpoint ID, the processing overhead of session information sharing may be reduced.

[0122] Additionally or alternatively, the follower connection management entities (52, 53) may be able to access a session table where session information is stored. Instead of directly transmitting their current session information to the connection management entity (54), the follower connection management entities (52, 53) may indirectly provide their current session information to the connection management entity (54) by updating the session table based on their current session information. Additionally or alternatively, the follower connection management entities (52, 53) may update the session table and transmit a session information update notification to the connection management entity (54) notifying that the session table has been updated.

[0123] At step (510), the connection management entity (52) may send a termination notification to the new leader connection management entity (54) indicating that it is about to be terminated.

[0124] In step (511), based on the received state information, the connection management entity (54) can reallocate session information for the connection management entity (52). The connection management entity (54) can identify a target of an event indicated in the state information received in step (501). Based on the fact that the target of the identified event is the connection management entity (52), the connection management entity (54) can reallocate session information for the connection management entity (52) to at least some of other connection management entities (e.g., connection management entities (53, 54)) other than the connection management entity (52). For example, the connection management entity (54) can reallocate session information for a first connection among the SCTP connections managed by the connection management entity (52) to the connection management entity (53) and can reallocate session information for a second connection among the SCTP connections to the connection management entity (54).

[0125] In one embodiment, the connection management entity (52), which is a previous leader, may include a session table that stores session information of some or all connection management entities within the vCU. Alternatively or additionally, the connection management entity (52) may manage (or access) a session table (or database) stored in an external storage device. The connection management entity (52) may transfer the session table to the connection management entity (54). Alternatively or additionally, the connection management entity (52) may transfer the authority to manage (or access) the session table (or database) stored in the external storage device to the connection management entity (54). Alternatively or additionally, the authority to manage the session table may be granted to the connection management entity (54) by the leader selection entity (56), the OAM entity (51), or an entity internal or external to the vCU-CP. Based on the session information of the connection management entities stored in the session table, the connection management entity (42) can reallocate the session information for the connection management entity (52) to other connection management entities other than the connection management entity (52) by taking into account the traffic balance between the connection management entities.

[0126] In step (512), the connection management entity (54) can transmit the session information reallocated in step (511) to the connection management entity (53). For example, based on the reallocation of session information for a first connection among the SCTP connections managed by the connection management entity (52) to the connection management entity (53), the connection management entity (54) can transmit session information for the first connection to the connection management entity (53).

[0127] In step (513-1), the connection management entity (54) may perform SCTP reconnection based on the reassigned session information. In step (513-2), the connection management entity (54) may perform SCTP reconnection based on the reassigned session information. For example, the connection management entity (54) may perform SCTP reconnection based on the session information reassigned to the connection management entity (54) in step (511). The connection management entity (53) may perform SCTP reconnection based on the received reassigned session information. For example, the connection management entity (53) and the connection management entity (54) may initiate connections with endpoints of the SCTP connection(s) included in their reassigned session information based on the reassigned session information. In one embodiment, the connection management entity (53) and the connection management entity (54) may perform a restart mechanism supported by SCTP based on the reallocated session information.

[0128] In step (514), if SCTP reconnection is completed, the connection management entity (53) may transmit reconnection completion information indicating that SCTP reconnection is completed to the connection management entity (54). For example, the reconnection completion information may indicate that the connection management entity (53) has established SCTP connections based on reallocated session information.

[0129] In step (515), the connection management entity (54) may transmit a response to the termination notification received in step (510) to the connection management entity (52). The connection management entity (54) may identify (or determine) that its SCTP reconnection is complete, and may transmit a response to the termination notification to the connection management entity (52) based on the fact that its SCTP reconnection is complete and the receipt of reconnection completion information from the connection management entity (53). For example, the response to the termination notification may indicate that the SCTP connections managed by the connection management entity (52) have been transferred to other connection management entity(ies).

[0130] In step (516), based on the response to the termination notification, the connection management entity (52) may complete the termination procedure. The connection management entity (52) may terminate its own operations (or the operations of its internal containers) after receiving the response to the termination notification. Upon termination of the connection management entity (52), SCTP connections managed by the connection management entity (52) may be released.

[0131] In step (517), the connection management entity (54) may transmit the reallocated session information in step (511) to the call processing entity (55). In response to receiving the reallocated session information, the call processing entity (55) may restart transmitting the processing response.

[0132] In step (518), the call processing entity (55) may transmit the pending processing response to the corresponding connection management entity. For example, if session information for a first SCTP connection among the SCTP connections managed by the connection management entity (52) is reassigned to the connection management entity (53), the call processing entity (55) may transmit the processing response(s) that should be transmitted to the endpoint associated with the first SCTP connection among the pending processing responses to the connection management entity (53). Similarly, if session information for a second SCTP connection among the SCTP connections managed by the connection management entity (52) is reassigned to the connection management entity (54), the call processing entity (55) may transmit the processing response(s) that should be transmitted to the endpoint associated with the second SCTP connection among the pending processing responses to the connection management entity (54).

[0133] In the method (500) of FIG. 5, the connection management entity (52) that is the target of the scaling-in event is not immediately terminated upon receiving state information. Instead, the connection management entity (52) may wait (or hold) its termination until the leader is re-elected and the SCTP connections managed by the connection management entity (52) are redistributed (or transferred) to other connection management entities. Accordingly, when the leader is selected as the target of the scaling-in event, the leader of the connection management entities is re-elected, and an abrupt closure of the SCTP connections managed by the connection management entity (52) can be avoided.

[0134] FIG. 6 illustrates a method (600) for at least partially reallocating session information between entities within a vCU-CP according to one embodiment of the present disclosure.

[0135] In the embodiment of FIG. 6, the OAM entity (61) may be implemented in a similar manner to the OAM entity (130) of FIG. 1 and may operate in a similar manner. The connection management entities (62, 63, 64) may be implemented in a similar manner to the connection management entity (111) of FIG. 1 and may operate in a similar manner. The call processing entity (65) may be implemented in a similar manner to the call processing entity (121) of FIG. 1 and may operate in a similar manner. The leader selection entity (66) may be implemented in a similar manner to the leader selection entity (140) of FIG. 1 and may operate in a similar manner.

[0136] In the embodiment of FIG. 6, the connection management entity (62) may be a leader of the connection management entities (62, 63, 64). The connection management entities (63, 44) may be follower connection management entities. In the embodiment of FIG. 6, a failure event may occur for the connection management entity (64). For example, the connection management entity (64) may be suddenly terminated. Referring to FIG. 6, through the method (600), the connection management entity (62) may reallocate session information of the connection management entity (64) to the connection management entity (62) and the connection management entity (63). Through the method (600), the connection management entity (62) may share the reallocated session information with the connection management entity (63). The method (600) may include steps (601 to 608). The method (600) is not limited to that illustrated in FIG. 6, and in one or more embodiments, the method (600) may further include steps not illustrated in FIG. 6, some of the steps in FIG. 6 may be omitted from the method (600), or the order of some of the steps in FIG. 6 may be changed.

[0137] In step (601), the OAM entity (61) may transmit status information to entities (62, 63, 65, 66) within the vCU-CP (100). The OAM entity (61) may detect that a failure has occurred in the connection management entity (64) and transmit status information to the entities (62, 63, 65, 66). In the embodiment of FIG. 6, the status information may indicate that a failure has occurred in the connection management entity (64).

[0138] In the embodiment of FIG. 6, the leader selection entity (66) can identify the target of the event indicated by the state information based on the received state information. The leader selection entity (66) can identify that the target of the event indicated by the state information is a follower (i.e., a connection management entity (64)) and not a leader (i.e., a connection management entity (62)). Based on identifying that the target of the event indicated by the state information is not a leader of the connection management entities, the leader selection entity (66) can withhold leader re-election.

[0139] In step (602), based on the status information received from the OAM entity (61), the call processing entity (65) may wait for transmission of a processing response. In the embodiment of FIG. 6, the status information may indicate that a failure has occurred for the connection management entity (64), and based on the status information, the call processing entity (65) may withhold transmission of the processing response(s) that are to be transmitted to the connection management entity (64).

[0140] In step (603), based on the status information received from the OAM entity (61), the connection management entity (62) can reallocate session information for the connection management entity (64). The connection management entity (62) can identify a target of an event indicated in the received status information. Based on the fact that the target of the identified event is the connection management entity (64), the connection management entity (62) can reallocate session information for the connection management entity (64) to at least some of other connection management entities (e.g., connection management entities (62, 43)) other than the connection management entity (64). For example, the connection management entity (62) can reallocate session information for a first connection among the SCTP connections managed by the connection management entity (64) to the connection management entity (63) and can reallocate session information for a second connection among the SCTP connections to the connection management entity (62).

[0141] In one embodiment, the connection management entity (62) may include a session table that stores session information of some or all of the connection management entities within the vCU-CP. Alternatively or additionally, the connection management entity (62) may manage (or access) a session table (or database) stored in an external storage device. Based on the session information of the connection management entities stored in the session table, the connection management entity (62) may reallocate the session information for the connection management entity (64) to other connection management entities other than the connection management entity (64). For example, the connection management entity (62) may reallocate the session information for the connection management entity (64) to other connection management entities other than the connection management entity (64) taking into account the traffic balance between the connection management entities or the number of SCTP connections assigned to each of the connection management entities.

[0142] In step (604), the connection management entity (62) can transmit the session information reallocated in step (603) to the connection management entity (63). For example, based on the reallocation of session information for a first connection among one or more SCTP connections managed by the connection management entity (64) to the connection management entity (63), the connection management entity (62) can transmit session information for the first connection to the connection management entity (63).

[0143] In step (605-1), the connection management entity (62) can perform SCTP reconnection based on the reassigned session information. In step (605-2), the connection management entity (63) can perform SCTP reconnection based on the reassigned session information. For example, the connection management entity (62) can perform SCTP reconnection based on the session information reassigned to the connection management entity (62) in step (603). The connection management entity (63) can perform SCTP reconnection based on the received reassigned session information. For example, the connection management entity (62) and the connection management entity (63) can initiate connections with endpoints of the SCTP connection(s) included in their reassigned session information based on the reassigned session information. In one embodiment, the connection management entity (62) and the connection management entity (63) may perform a restart mechanism supported by SCTP based on the reallocated session information.

[0144] In step (606), if SCTP reconnection is completed, the connection management entity (63) may transmit reconnection completion information indicating that SCTP reconnection is completed to the connection management entity (62). For example, the reconnection completion information may indicate that the connection management entity (63) has established SCTP connections based on reallocated session information.

[0145] In step (607), the connection management entity (62) may transmit the reallocated session information in step (603) to the call processing entity (65). In response to receiving the reallocated session information, the call processing entity (65) may restart transmitting the processing response.

[0146] In step (608), the call processing entity (65) may transmit the pending processing response to the corresponding connection management entity. For example, if session information for a first SCTP connection among the SCTP connections managed by the connection management entity (64) is reassigned to the connection management entity (63), the call processing entity (65) may transmit the processing response(s) that should be transmitted to the endpoint associated with the first SCTP connection among the pending processing responses to the connection management entity (63). Similarly, if session information for a second SCTP connection among the SCTP connections managed by the connection management entity (64) is reassigned to the connection management entity (63), the call processing entity (65) may transmit the processing response(s) that should be transmitted to the endpoint associated with the second SCTP connection among the pending processing responses to the connection management entity (64).

[0147] In the method (600) of FIG. 6, the connection management entity (64) that is the target of the failure occurrence event can be immediately terminated. Even if the connection management entity (64) is suddenly terminated, the leader connection management entity (62) can redistribute the SCTP connections managed by the connection management entity (64) to other connection management entities based on the session information of the connection management entity (64) that it was managing.

[0148] FIG. 7 illustrates a method for at least partially reallocating session information between entities within a vCU according to one embodiment of the present disclosure.

[0149] In the embodiment of FIG. 7, the OAM entity (71) may be implemented in a similar manner to the OAM entity (130) of FIG. 1 and may operate in a similar manner. The connection management entities (72, 73, 74) may be implemented in a similar manner to the connection management entity (111) of FIG. 1 and may operate in a similar manner. The call processing entity (75) may be implemented in a similar manner to the call processing entity (121) of FIG. 1 and may operate in a similar manner. The leader selection entity (76) may be implemented in a similar manner to the leader selection entity (140) of FIG. 1 and may operate in a similar manner.

[0150] In the embodiment of FIG. 7, the connection management entity (72) may be the current leader of the connection management entities (72, 73, 74). The connection management entities (73, 74) may be follower connection management entities. In the embodiment of FIG. 7, a failure event may occur for the connection management entity (72). For example, the connection management entity (72) may be suddenly terminated. Through the method (700), the connection management entity (74) may be elected as the new leader, reallocate session information of the connection management entity (72), and share the reallocated session information with the entities (73, 75). The method (700) may include steps (701 to 712). The method (700) is not limited to that illustrated in FIG. 7, and in one or more embodiments, the method (700) may further include steps not illustrated in FIG. 7, some of the steps in FIG. 7 may be omitted from the method (700), or the order of some of the steps in FIG. 7 may be changed.

[0151] In step (701), the OAM entity (71) may transmit status information to entities (73, 74, 75, 76) within the vCU. The OAM entity (71) may detect that a failure has occurred in the connection management entity (72) and transmit status information to the entities (73, 74, 75, 76). In the embodiment of FIG. 7, the status information may indicate that a failure has occurred in the connection management entity (72).

[0152] In step (702), based on the status information received from the OAM entity (71), the call processing entity (75) may wait for transmission of a processing response. For example, the call processing entity (75) may withhold transmission of call processing response(s) that are to be transmitted to the connection management entity (72) that is the target of the event indicated in the received status information.

[0153] In step (703), the leader selection entity (76) may re-elect a leader based on the received status information. The leader selection entity (76) may store IDs of connection management entities within the current vCU and information indicating which entity among the connection management entities is the leader. The leader selection entity (76) may identify that the target of the event indicated by the status information is the current leader of the connection management entities (i.e., the connection management entity (72)). Based on identifying that the target of the event indicated by the status information is the leader of the connection management entities, the leader selection entity (76) may decide to re-elect a leader. The leader selection entity (76) may re-elect one of the connection management entities (73, 74) as the new leader. In the embodiment of FIG. 7, the leader selection entity (76) may select the connection management entity (74) as the new leader.

[0154] In step (704), the leader selection entity (76) may transmit leader re-selection information to entities (73, 74, 75) within the vCU. The leader re-selection information may indicate that the connection management entity (74) has been selected as the new leader of the connection management entities. The leader re-selection information may indicate that the leader of the connection management entities has changed from the connection management entity (72) to the connection management entity (74).

[0155] In step (705), the connection management entity (74) may transition from a follower to a leader based on the received leader re-election information. The connection management entity (74) may initialize at least some of its functions to perform its role as the new leader. The connection management entity (74) may prepare to receive session information from the follower connection management entity (73).

[0156] In step (706), the connection management entity (73) may transmit session information of the connection management entity (73) to a new leader, i.e., the connection management entity (74). In one embodiment, the connection management entity (73) may segment and transmit its session information to the connection management entity (74). The connection management entity (73) may transmit a first part of its session information during a first time period and a second part of its session information during a second time period. For example, the connection management entity (73) may segment and transmit its session information to the connection management entity (74) by NR interface type (e.g., F1, E1, NG, X2, or Xn) and / or endpoint (e.g., gNB) ID. The connection management entities may have a packet processing structure per NR interface type and / or endpoint ID. Therefore, by dividing session information by NR interface type and / or endpoint ID unit and transmitting and / or receiving it, the processing overhead of session information sharing can be reduced.

[0157] Additionally or alternatively, the follower connection management entity (73) may be able to access a session table where session information is stored. Instead of directly transmitting its current session information to the connection management entity (74), the follower connection management entity (73) may indirectly provide its current session information to the connection management entity (74) by updating the session table based on its current session information. Additionally or alternatively, the follower connection management entity (73) may update the session table and transmit a session information update notification to the connection management entity (74) notifying that the session table has been updated.

[0158] In step (707), based on the received state information and session information, the connection management entity (74) can reallocate session information for the connection management entity (72). The connection management entity (74) can identify a target of an event indicated in the state information received in step (701). Based on the identified target of the event being the connection management entity (72), the connection management entity (74) can reallocate the session information for the connection management entity (72) to at least some of other connection management entities (e.g., connection management entities (73, 74)) other than the connection management entity (72). For example, the connection management entity (74) can reallocate session information for a first connection among the SCTP connections managed by the connection management entity (72) to the connection management entity (73) and can reallocate session information for a second connection among the SCTP connections to the connection management entity (74).

[0159] In one embodiment, the connection management entity (74) can determine the session information of the connection management entity (72) based on the session information received from the remaining connection management entities (73) and its own session information. For example, the connection management entity (74) can obtain a session table from a database in which the session table is stored. The connection management entity (74) can determine the session information that does not correspond to the session information of the remaining connection management entities (73, 74) among the session information stored in the session table as the session information of the connection management entity (72). The connection management entity (74) can reallocate the session information determined as the session information of the connection management entity (72) to the remaining connection management entities (73, 74) and update the session table based on the reallocation of the session information.

[0160] In one embodiment, access (or management) to the session table may be granted to a new leader connection management entity (74) by a leader election entity (76), an OAM entity (71), or an entity internal or external to the vCU. Based on the session information of the connection management entities stored in the session table, the connection management entity (74) may reallocate session information for the connection management entity (72) to other connection management entities other than the connection management entity (72) in consideration of traffic balance among the connection management entities.

[0161] In step (708), the connection management entity (74) can transmit the session information reallocated in step (707) to the connection management entity (73). For example, based on the reallocation of session information for a first connection among the SCTP connections managed by the connection management entity (72) to the connection management entity (73), the connection management entity (74) can transmit session information for the first connection to the connection management entity (73).

[0162] In step (709-1), the connection management entity (73) may perform SCTP reconnection based on the reassigned session information. In step (709-2), the connection management entity (74) may perform SCTP reconnection based on the reassigned session information. For example, the connection management entity (74) may perform SCTP reconnection based on the session information reassigned to the connection management entity (74) in step (707). The connection management entity (73) may perform SCTP reconnection based on the received reassigned session information. For example, the connection management entity (73) and the connection management entity (74) may initiate connections with endpoints of the SCTP connection(s) included in their reassigned session information based on the reassigned session information. In one embodiment, the connection management entity (73) and the connection management entity (74) may perform a restart mechanism supported by SCTP based on the reallocated session information.

[0163] In step (710), if SCTP reconnection is completed, the connection management entity (73) may transmit reconnection completion information indicating that SCTP reconnection is completed to the connection management entity (74). For example, the reconnection completion information may indicate that the connection management entity (73) has established SCTP connections based on reallocated session information.

[0164] In step (711), the connection management entity (74) may transmit the reallocated session information in step (707) to the call processing entity (75). In response to receiving the reallocated session information, the call processing entity (75) may restart transmitting the processing response.

[0165] In step (712), the call processing entity (75) may transmit the pending processing response to the corresponding connection management entity. For example, if session information for a first SCTP connection among the SCTP connections managed by the connection management entity (72) is reassigned to the connection management entity (73), the call processing entity (75) may transmit the processing response(s) that should be transmitted to the endpoint associated with the first SCTP connection among the pending processing responses to the connection management entity (73). Similarly, if session information for a second SCTP connection among the SCTP connections managed by the connection management entity (72) is reassigned to the connection management entity (74), the call processing entity (75) may transmit the processing response(s) that should be transmitted to the endpoint associated with the second SCTP connection among the pending processing responses to the connection management entity (74).

[0166] In the method (700) of FIG. 7, the connection management entity (72) that is the target of the failure event can be immediately terminated. Even if the existing leader connection management entity (72) is suddenly terminated, another connection management entity can be selected as the new leader connection management entity, and the SCTP connections managed by the connection management entity (72) that has failed can be redistributed to other connection management entities.

[0167] FIG. 8 illustrates a method (800) for at least partially reallocating session information by a connection management entity according to one embodiment of the present disclosure.

[0168] Referring to FIG. 8, the method (800) may include steps (801 to 804). In one embodiment, the method (800) may be performed by a first entity of the vCU-CP (100) of FIG. 1. The method (800) may be performed by a first entity (e.g., a leader connection management entity) that manages one or more SCTP connections in the vCU-CP (100).

[0169] In step (801), the first entity may receive status information from the OAM entity. The OAM entity, which manages the lifetime of the vCU-CP (100), may detect an event that has occurred within the vCU-CP (100). In one embodiment, the OAM entity may detect a scaling-in event for a third entity or a failure event for the third entity. The OAM entity may forward status information indicating the detected event to some or all entities of the vCU-CP (100). For example, the status information may indicate a scaling-in event for the third entity or a failure event for the third entity.

[0170] In step (802), the first entity may reassign a first portion of session information for one or more SCTP connections managed by a third entity to a second entity based on state information. The first entity may identify that the target of the event indicated by the state information is the third entity managing the SCTP connections, and reassign session information of sessions managed by the third entity to at least some of the entities managing the SCTP connections, excluding the third entity.

[0171] In step (803), the first entity may transmit the first portion of the reallocated session information to the second entity. Additionally or alternatively, the first entity may reallocate the second portion of the reallocated session information to itself and temporarily or non-temporarily store the second portion of the reallocated session information. Additionally or alternatively, the first entity may forward the reallocated session information to corresponding entities.

[0172] In step (804), the first entity may receive completion information from the second entity indicating that the SCTP reconnection of the second entity is completed. The second entity may perform SCTP reconnection with the endpoint based on the first part of the reassigned session information received in step (803). For example, the second entity may perform an SCTP restart mechanism based on the first part of the reassigned session information. Based on the completion of the SCTP reconnection, the second entity may transmit completion information indicating that the SCTP reconnection of the second entity is completed to the first entity.

[0173] Alternatively or additionally, the state information may indicate that a third entity is a target for scaling-in. The step of reallocating the first portion of the session information may include: receiving a termination notification from the third entity, indicating that the third entity is about to be terminated; and, in response to the termination notification, reallocating the first portion of the session information, corresponding to at least some of the one or more SCTP connections managed by the third entity, to the second entity.

[0174] Alternatively or additionally, the method (800) may further include the step of transmitting a message indicating that the transfer of one or more SCTP connections managed by the third entity has been completed, at least based on the completion information.

[0175] Alternatively or additionally, the first part of the reallocated session information may include at least one of: an ID of the second entity, an ID of the server containing the first entity, an interface type corresponding to the SCTP connection, a number of SCTP connections for the interface type, and information for network address translation associated with the first SCTP connection.

[0176] Alternatively or additionally, the method (800) may further include the step of reassigning a second portion of session information for a third entity to the first entity based on the state information; and performing an SCTP reconnection based on the second portion of the reassigned session information.

[0177] Alternatively or additionally, the method (800) may further include providing a second portion of the reallocated session information to a fourth entity; and receiving, from the fourth entity, a processing response message for an endpoint connected via SCTP connections corresponding to the reallocated second portion. In one embodiment, the fourth entity may be any one of the call processing entities (121 to 12M) of FIG. 1.

[0178] FIG. 9 illustrates a method (900) for managing session information by a connection management entity according to one embodiment of the present disclosure.

[0179] Referring to FIG. 9, the method (900) may include steps (901, 902). In one embodiment, the method (900) may be performed by a first entity of the vCU-CP (100) of FIG. 1. The method (900) may be performed by a first entity (e.g., a leader connection management entity) that manages one or more SCTP connections in the vCU-CP (100).

[0180] In step (901), the first entity may obtain session information about the third entity from a session table that stores session information about the third entity. In one embodiment, the first entity may include a session table that stores session information about some or all connection management entities within the vCU-CP. Alternatively or additionally, the session table may be stored in an external database (or storage device) of the first entity. The first entity may manage (or access) the session table (or database) stored in the external storage device. The first entity may obtain session information about the third entity from the session table. Based on the session information about the third entity obtained from the session table, the first entity may reallocate some or all of the session information about the third entity to another entity other than the third entity, for example, a second entity.

[0181] In step (902), the first entity may update the session table based on the reassignment of the first portion of the session information to the second entity. The first entity may reassign the session information of the third entity to an entity(ies) other than the third entity, and update the session table based on the reassigned session information. For example, the first entity may map the first portion of the session information of the third entity stored in the session table to the second entity.

[0182] In one embodiment, in response to a new leader entity being elected (e.g., a new leader connection management entity), the session table may be managed by the new leader entity instead of the first entity. The session table management authority may be granted to the new leader entity by the first entity, the leader election entity OAM entity, or an entity internal or external to vCU-CP.

[0183] In one embodiment, concurrently with the first entity, another entity within the vCU-CP (e.g., a follower connection management entity) may also access the session table. The entity may update the session table based on its current session information periodically, aperiodically, when its session information changes, or upon request from another entity (e.g., a leader connection management entity, an OAM entity, a leader election entity, or a scaling agent). The first entity may obtain session information of other entities indirectly from the session table, instead of directly receiving it from other entities.

[0184] Additionally or alternatively, if the follower connection management entities have access to the session table, the follower connection management entities can update the session table instead of directly transmitting their current session information to the leader connection management entity. Additionally or alternatively, after updating the session table, the follower connection management entities can notify the leader connection management entity that they have updated the session table. The leader connection management entity can obtain the updated session information of the follower connection management entities from the session table.

[0185] Additionally or alternatively, if the follower connection management entities have access to the session table, a new leader connection management entity may be selected. The new leader connection management entity may indirectly obtain the session information of the follower connection management entities from the database (or storage device) where the session table is stored. The new leader connection management entity may perform the role of the leader entity based on the session information obtained from the session table.

[0186] FIG. 10 illustrates a method (1000) for at least partially reallocating session information by a connection management entity according to one embodiment of the present disclosure.

[0187] Referring to FIG. 10, the method (1000) may include steps (1001 to 1004). In one embodiment, the method (1000) may be performed by a first entity of the vCU-CP (100) of FIG. 1. The method (1000) may be performed by a first entity (e.g., a leader connection management entity) that manages one or more SCTP connections in the vCU-CP (100). However, the present disclosure is not limited thereto, and steps (1001 to 1004) may be performed individually or in combination by any electronic device. The method (1000) according to one embodiment of the present disclosure is not limited to that illustrated in FIG. 10, and any one of the steps illustrated in FIG. 10 may be omitted, and steps not illustrated in FIG. 10 may be further included. In one or more embodiments, the order of at least some of the steps (1001 to 1004) may be changed.

[0188] In step (1001), the first entity may receive status information from the OAM entity. The OAM entity, which manages the lifetime of the vCU-CP (100), may detect an event that has occurred within the vCU-CP (100). In one embodiment, the OAM entity may detect a scaling-in event for the first entity. The OAM entity may forward status information indicating the detected event to some or all entities of the vCU-CP (100). For example, the status information may indicate that the first entity is a target for scaling-in.

[0189] At step (1002), the first entity may initiate a termination procedure based on state information. If the state information indicates that the first entity is a target for scaling-in, the first entity designated as a target for scaling-in may initiate a termination procedure. The first entity may not be terminated immediately, but may wait a predetermined amount of time before being terminated. In one embodiment, the termination procedure may be a graceful termination procedure provided by Kubernetes. Alternatively or additionally, the first entity may send a notification to the second entity indicating that it is about to be terminated.

[0190] Alternatively or additionally, the first entity can complete the termination procedure after the sessions of the SCTP connections it managed have been transferred to other entities. This prevents the first entity from being terminated without transferring the sessions, resulting in unexpected session closures.

[0191] At step (1003), the first entity may receive information indicating that the second entity has been selected as the leader. Based on the state information indicating that the first entity is a target for scaling-in, the second entity may be selected as the new leader. Based on the information indicating that the second entity has been selected as the leader, the first entity may transition from being a leader to being a follower.

[0192] In step (1004), the first entity may provide the second entity with the session information of the first entity and the session information of the third entity. Based on the information indicating that the second entity has been selected as the leader, the first entity may provide the second entity with the session information of the first entity and the session information of the third entity that it managed. In one embodiment, the first entity may directly transmit at least a portion of the session information of the first entity and the session information of the third entity to the second entity. For example, the first entity may divide the session information by interface type and / or by gNB ID and transmit it to the second entity. Alternatively or additionally, the first entity may indirectly provide at least a portion of the session information of the first entity and the session information of the third entity to the second entity by granting the second entity permission to the database in which the session information of the first entity and the session information of the third entity are stored.

[0193] Alternatively or additionally, the method (1000) may further include the step of receiving, from the second entity, a message indicating that the transfer of SCTP connections managed by the first entity is complete. Alternatively or additionally, the method (1000) may further include the step of completing a termination procedure of the first entity in response to the message indicating that the transfer of SCTP connections managed by the first entity is complete.

[0194] FIG. 11 illustrates a method (1100) for at least partially reallocating session information by a connection management entity according to one embodiment of the present disclosure.

[0195] Referring to FIG. 11, the method (1100) may include steps (1101 to 1104). In one embodiment, the method (800) may be performed by a first entity of the vCU-CP (100) of FIG. 1. The method (800) may be performed by a first entity (e.g., a follower connection management entity) that manages one or more SCTP connections in the vCU-CP (100). However, the present disclosure is not limited thereto, and steps (1101 to 1104) may be performed individually or in combination by any electronic device. The method (1100) according to one embodiment of the present disclosure is not limited to that illustrated in FIG. 11, and any one of the steps illustrated in FIG. 11 may be omitted, and steps not illustrated in FIG. 11 may be further included. In one or more embodiments, the order of at least some of the steps (1101 to 1104) may be changed.

[0196] In step (1101), the first entity may receive status information from the OAM entity. The OAM entity, which manages the lifetime of the vCU-CP (100), may detect an event that has occurred within the vCU-CP (100). In one embodiment, the OAM entity may detect a scaling-in event for a third entity or a failure event for the third entity. The OAM entity may forward status information indicating the detected event to some or all entities of the vCU-CP (100). Alternatively or additionally, the status information may indicate that the third entity is a target for scaling-in or that a failure has occurred in the third entity.

[0197] In step (1102), the first entity may receive reassigned session information for the first entity from the second entity based on the fact that the target of the state information is the third entity. In one embodiment, the first entity may receive reassigned session information for the first entity from the second entity that is not the target of the state information. In one embodiment, the reassigned session information for the first entity may include session information corresponding to the first SCTP connection that was reassigned from the third entity to the first entity.

[0198] In step (1103), the first entity may perform SCTP reconnection based on the reassigned session information. The first entity may perform SCTP reconnection with the endpoint based on the reassigned session information received in step (1102). For example, the first entity may perform an SCTP restart mechanism based on the reassigned session information.

[0199] In step (1104), the first entity may transmit a message to the second entity indicating completion of the SCTP reconnection. Based on the completion of the SCTP reconnection, the first entity may transmit completion information to the second entity indicating that the SCTP reconnection of the first entity has been completed.

[0200] Alternatively or additionally, the method (1100) may include receiving a processing response to a request originating from an endpoint of the first SCTP connection from a fourth entity. In one embodiment, the fourth entity may be any one of the call processing entities (121, 122, …, 12M) of FIG. 1.

[0201] Alternatively or additionally, the method (1100) may include receiving leader re-election information indicating that a second entity has been re-elected as a leader.

[0202] Alternatively or additionally, the method (1100) may include, in response to the leader re-election information, transmitting session information of the first entity to the second entity; and, in response to the transmitting of the session information of the first entity, receiving reassigned session information for the first entity.

[0203] Alternatively or additionally, the method (1100) may include: transmitting, during a first time period, session information associated with a first interface type from among the session information of the first entity to a third entity; and transmitting, during a second time period, session information associated with a second interface type from among the session information of the first entity to the third entity.

[0204] Alternatively or additionally, the method (1100) may include: transmitting, during a first time period, to a second entity, session information associated with a first network entity ID among the session information of the first entity; and transmitting, during a second time period, to the second entity, session information associated with a second network entity ID among the session information of the first entity.

[0205] FIG. 12 illustrates a block diagram of a server device (1200) according to one embodiment of the present disclosure.

[0206] The server device (1200) illustrated in FIG. 12 may be a network entity constituting at least one of the network entities described in FIG. 1. For example, the server device (1200) may be a communication device constituting the vRAN system (10) of FIG. 1. The server device (1200) may be a server device configured with a vCU-CP (100), a vDU (11), an eNB (12), a gNB (13), a virtualization core (14), a vCU-UP (15), or a router (16) of FIG. 1. The server device (1200) may be a server device or a network entity for constituting the vRAN system (10), which is not illustrated in FIG. 1. The server device (1200) may be a server device constituting at least some entities of the vCU-CP (100). For example, at least one of the connection management entities (111 to 11N), call processing entities (121 to 12M), OAM entity (130), or leader selection entity (140) may be configured on the server device (1200).

[0207] In one embodiment of the present disclosure, the server device (1200) may include, but is not limited to, at least one processor (1210) and a memory (1220). The processor (1210) may be electrically connected to components included in the server device (1200) and may execute operations or data processing related to control and / or communication of the components included in the server device (1200). In one embodiment of the present disclosure, the processor (1210) may load and process a request, command, or data received from at least one of the other components into a memory, and store the processed result data in the memory. According to various embodiments, the processor (1210) may include at least one of a general-purpose processor such as a central processing unit (CPU), an application processor (AP), a digital signal processor (DSP), a graphics-only processor such as a graphics processing unit (GPU), a vision processing unit (VPU), or an artificial intelligence-only processor such as a neural processing unit (NPU).

[0208] In one embodiment, the processor (1210) may include multiple processors. The functions of at least some modules included in each unit (or entity) conceptually separating the functions of the server device (1200) may be implemented by multiple processors. In this case, the multiple processors may be implemented as separate hardware to perform each operation.

[0209] The processor (1210) may be controlled to process input data according to predefined operation rules, algorithms, methods, or models stored in the memory (1220). The processor (1210) may be controlled to process the input data based on the data stored in the memory (1220). The processor (1210) may perform operations of predefined operation rules, algorithms, methods, or models stored in the memory (1220) using the input data. The operations of the processor (1210) may also be implemented as software modules stored in the memory (1220). For example, the software modules may be stored in the memory (1220) and may be operated by being executed by the processor (1210).

[0210] The memory (1220) is electrically connected to the processor (1210) and can store one or more modules, algorithms, operation rules, models, programs, commands, or data related to the operations of the components included in the server device (1200). For example, the memory (1220) can store one or more modules, algorithms, operation rules, models, programs, commands, or data for processing and controlling the processor (1210). The memory (1220) can include at least one type of storage medium among a flash memory type, a hard disk type, a multimedia card micro type, a card type memory (e.g., SD or XD memory, etc.), a RAM (Random Access Memory), a SRAM (Static Random Access Memory), a ROM (Read-Only Memory), an EEPROM (Electrically Erasable Programmable Read-Only Memory), a PROM (Programmable Read-Only Memory), a magnetic memory, a magnetic disk, and an optical disk, but is not limited thereto.

[0211] In one embodiment, the memory (1220) may store data or information identified, acquired, generated, or determined by the server device (1200). The memory (1220) may store the data or information identified, acquired, generated, or determined by the server device (1200) in a compressed form. For example, if a leader connection management entity is configured on the server device (1200), the memory (1220) may store a session information table created, managed, and updated by the leader connection management entity. For example, if a leader selection entity is configured on the server device (1200), the memory (1220) may store the ID of the leader connection management entity.

[0212] Some modules that perform at least one operation of the server device (1200) may be implemented as hardware modules, software modules, and / or a combination thereof. The memory (1220) may include software modules that perform at least some of the operations of the server device (1200) described above. In one embodiment of the present disclosure, the modules included in the memory (1220) may perform operations by being executed by the processor (1210). For example, the modules (i.e., software modules) included in the memory (1220) may include programs, models, or algorithms that are executed according to the control or instructions of the processor (1210) and are configured to perform operations that derive output data for input data. Some modules that perform at least one operation of the server device (1200) may be composed of a plurality of sub-modules or may constitute a single module.

[0213] The server device (1200) may include more components than those illustrated in FIG. 12. In one embodiment of the present disclosure, the server device (1200) may further include a communication interface (or communication module) for communicating with an external device (e.g., an external network entity or an external network node). For example, the server device (1200) may include a wireless communication module (e.g., a cellular communication module, a short-range wireless communication module, or a Global Navigation Satellite System (GNSS) communication module) or a wired communication module (e.g., a Local Area Network (LAN) communication module, or a power line communication module), and may use the corresponding communication module to communicate with an external electronic device via a short-range communication network (e.g., Bluetooth, WiFi direct, or Infrared Data Association (IrDA)) or a long-range communication network (e.g., a cellular network, the Internet, or a computer network (e.g., a LAN or a Wide Area Network (WAN))). In one embodiment of the present disclosure, the server device (1200) may further include an input / output device and / or an input / output interface.

[0214] In one embodiment, the server device (1200) may include at least one processor (1210) and a memory (1220) electrically coupled thereto. The at least one processor (1210) may individually or in combination execute instructions stored in the memory (1220), thereby causing the server device (1200) to perform at least one step of at least one of the methods described with reference to FIGS. 4 to 11.

[0215] In the present disclosure, overlapping descriptions in FIGS. 1 to 12 may be omitted, and one or more of the above-described embodiments may be applied / implemented in combination with each other. In the present disclosure, an operation described as being performed by a module may be executed / performed by an electronic device in which the module is included or stored, or may be executed / performed by the control of at least one processor of the electronic device in which the module is included. An operation described as being performed by an electronic device may be executed / performed by a module included or stored in the electronic device, or may be performed by the control of at least one processor of the electronic device using a module included or stored in the electronic device.

[0216] A device-readable storage medium may be provided in the form of a non-transitory storage medium. Here, the term "non-transitory storage medium" simply means a tangible device that does not contain signals (e.g., electromagnetic waves). This term does not distinguish between cases where data is permanently stored in the storage medium and cases where data is temporarily stored. For example, a "non-transitory storage medium" may include a buffer in which data is temporarily stored.

[0217] According to one embodiment, the method according to various embodiments disclosed in the present document may be provided as included in a computer program product. The computer program product may be traded as a product between a seller and a buyer. The computer program product may be distributed in the form of a machine-readable storage medium (e.g., compact disc read-only memory (CD-ROM)), or may be distributed online (e.g., downloaded or uploaded) through an application store or directly between two user devices (e.g., smartphones). In the case of online distribution, at least a portion of the computer program product (e.g., a downloadable app) may be temporarily stored or temporarily generated in a machine-readable storage medium, such as the memory of a manufacturer's server, an application store's server, or an intermediary server.

[0218] Although the embodiments described above have been described with limited examples and drawings, those skilled in the art will appreciate that various changes and modifications may be made based on the above description. For example, appropriate results may still be achieved even if the described techniques are performed in a different order than described, and / or components such as the described computer system or modules are combined or combined in a different manner than described, or are replaced or substituted with other components or equivalents.

Claims

1. A method (800) performed by a first entity managing one or more Stream Control Transmission Protocol (SCTP) associations in a virtualized central unit (vCU), Step (801) of receiving status information from an OAM (Operation Administration Maintenance) entity; A step (802) of reallocating a first part of session information for one or more SCTP connections managed by a third entity to a second entity based on the above state information; a step (803) of transmitting a first part of the reallocated session information to the second entity; and A method comprising the step (804) of receiving completion information from the second entity indicating that the SCTP reconnection of the second entity has been completed.

2. In paragraph 1, A method wherein the above status information indicates that the third entity is subject to scaling-in or that a failure has occurred in the third entity.

3. In paragraph 1 or 2, The above state information indicates that the third entity is the target of scaling-in, The steps for reallocating the first part of the above session information are: A step of receiving a termination notification from the third entity, notifying that the third entity is about to be terminated; and A method comprising, in response to said termination notification, reassigning a first portion of said session information corresponding to at least some of said one or more SCTP connections managed by said third entity to said second entity.

4. In any one of paragraphs 1 to 3, A method further comprising the step of transmitting a message indicating that the transfer of one or more SCTP connections managed by the third entity has been completed, based at least on the completion information.

5. In any one of paragraphs 1 to 4, a step of reassigning a second part of the session information for the third entity to the first entity based on the state information; and A method further comprising the step of performing SCTP reconnection based on a second part of the reassigned session information.

6. In paragraph 5, providing a second portion of the above reallocated session information to a fourth entity; and A method further comprising the step of receiving, from the fourth entity, a processing response message for an endpoint connected via SCTP connections corresponding to the reallocated second portion.

7. A method (1000) performed by a first entity managing one or more Stream Control Transmission Protocol (SCTP) associations in a virtualized central unit (vCU), Step (1001) of receiving status information from an OAM (Operation Administration Maintenance) entity; Based on the above status information, a step (1002) of starting a termination procedure; Step (1003) of receiving information indicating that a second entity has been selected as a leader; and A method comprising the step (1004) of providing session information of the first entity and session information of the third entity to the second entity.

8. In paragraph 7, A method wherein the above state information indicates that the first entity is a target of scaling-in.

9. In paragraph 8, A method further comprising the step of transmitting a notification to the second entity informing that the first entity is about to be terminated.

10. In paragraph 9, A step of receiving a message from the second entity indicating that the transfer of SCTP connections managed by the first entity has been completed; and A method further comprising, in response to the above message, completing a termination procedure of the first entity.

11. A method (1100) performed by a first entity managing one or more Stream Control Transmission Protocol (SCTP) connections in a virtualized central unit (vCU), Step (1101) of receiving status information from an OAM (Operation Administration Maintenance) entity; A step (1102) of receiving reallocated session information for the first entity from the second entity based on the target of the status information being a third entity; Step (1103) of performing SCTP reconnection based on the above reallocated session information; and A method comprising the step (1104) of transmitting a message indicating completion of SCTP reconnection to the second entity.

12. In paragraph 11, A method wherein the above status information indicates that the third entity is subject to scaling-in or that a failure has occurred in the third entity.

13. In paragraph 11 or 12, The reassigned session information for the first entity includes session information corresponding to the first SCTP connection that was reassigned from the third entity to the first entity, The method further comprises the step of receiving, from a fourth entity, a processing response to a request generated from an endpoint of the first SCTP connection.

14. In any one of paragraphs 11 to 13, A method wherein the step of receiving reassigned session information for the first entity comprises the step of receiving leader re-election information indicating that the second entity has been re-elected as a leader.

15. In paragraph 14, The step of receiving reallocated session information for the first entity comprises: In response to the leader re-selection information, a step of transmitting session information of the first entity to the second entity; and A method comprising the step of receiving reallocated session information for the first entity in response to transmission of session information of the first entity.

Images