Device, method and computer program

Abstract

An apparatus is provided, the apparatus comprising means for receiving information regarding an identification of a network function set associated with at least one packet data network connection. The means is further configured to transfer the at least one packet data network connection from the network function instance to another network function instance included in the network function set in response to receiving an indication that the network function instance of the network function set supporting the at least one packet data network connection is no longer available.

Description

Technical Field

[0001] The present application relates to an apparatus, a method and a computer program. Background Art

[0002] A communication system is a facility for enabling communication sessions between two or more entities (such as user terminals, base stations / access points, and / or other nodes) by providing carrier waves between the various entities involved in the communication path. For example, a communication system may be provided by a communication network and one or more compatible communication devices. A communication session may include, for example, communications of data used to carry communications, such as voice, electronic mail (email), text messages, multimedia, and / or content data. Non-limiting examples of the services provided include two-way or multi-way calls, data communications or multimedia services, and access to data network systems such as the Internet. Summary of the invention

[0003] According to one aspect, an apparatus is provided that includes components for: receiving information about an identification of a network function set associated with at least one packet data network connection; and in response to receiving an indication that a network function instance of the network function set supporting the at least one packet data network connection is no longer available, transferring the at least one packet data network connection from the network function instance to another network function instance included in the network function set.

[0004] The means for transferring may also be configured to initiate a transfer of the at least one packet data network connection from the network function instance to another network function instance included in the network function set.

[0005] The means for transferring may also be configured to receive a transfer request of at least one packet data network connection from the network function instance to another network function instance included in the network function set.

[0006] The information regarding the identification of the network capability set may be received during one of a packet data network connection establishment and an inter-system mobility of the packet data connection.

[0007] The component may also be configured to perform, in response to receiving an indication that the network function instance is no longer available, maintaining a context of the at least one packet data network connection and transferring the at least one packet data network connection to another network function instance included in the network function set.

[0008] The context of at least one packet data network connection may include at least one of the following: an international mobile subscriber identity, an international mobile equipment identity, a globally unique temporary identity, an access point name, a packet data gateway identifier, a packet data gateway Internet Protocol address of an S5 or S8 interface, a packet data gateway tunnel endpoint identifier of an S5 or S8 interface, a mobility management entity Internet Protocol address of an S11 interface, a mobility management entity tunnel endpoint identifier of an S11 interface, and a serving gateway Internet Protocol address of an S11 interface.

[0009] The component may be further configured to perform: providing a session request message to the network function instance during establishment of the packet data network connection, the session request message including an indication that the apparatus supports transfer of the packet data network connection from one network function instance to another network function instance in the set of network functions.

[0010] The component may also be configured to perform: providing a mobility bearer request message to the network function instance during inter-system mobility of the packet data connection, the mobility bearer request message including an indication that the apparatus supports transfer of the packet data network connection from one network function instance to another network function instance in the network function set.

[0011] The component may also be configured to perform: selecting, for at least one packet data network connection, another network function instance of the network function set to be transferred to based on the received information about the identification of the network function set.

[0012] The component may also be configured to perform: receiving an indication that another network function instance has been selected for at least one packet data network connection.

[0013] The component may also be configured to perform: when transferring at least one packet data network connection to another network function instance, providing a message to the other network function instance, the message including an identifier of a user subscription or user equipment associated with the at least one packet data network connection, and information about a default bearer of the at least one packet data network connection.

[0014] The component may also be configured to perform: receiving information about another network function instance to which the at least one packet data network connection is being transferred.

[0015] The component may also be configured to perform: receiving information about another network function instance, the information including a fully qualified domain name of the another network function instance.

[0016] The information about the other network function instance may include an Internet Protocol address and a control plane identifier of a General Packet Radio Service Tunneling Protocol control plane tunnel for the packet data network connection at the other network function instance.

[0017] At least one of the network function instance and the other network function instance may include a session management function / packet data network gateway control plane SMF / PGW-c instance.

[0018] The information about the identification of the network capability set may be included in one of the create session response message and the modify bearer response message.

[0019] The information about the identification of the network capability set may include a domain name of the network capability set.

[0020] The information about the identity of the network capabilities set includes a fully qualified domain name of the network capabilities set.

[0021] A network function instance may no longer be available due to at least one of a failure, a restart, and a scale-in.

[0022] An indication that the network function instance is unavailable is received in a gateway restart notification message.

[0023] The component may also be configured to perform: notifying the home subscriber server that the at least one packet data network connection has been transferred from the network function instance to another network function instance, enabling the home subscriber server to update stored information about the at least one packet data network connection.

[0024] The apparatus may be included in one of a mobility management entity and a serving gateway entity.

[0025] According to another aspect, a method is provided, the method comprising: receiving information about an identification of a network function set associated with at least one packet data network connection; and in response to receiving an indication that a network function instance of the network function set supporting the at least one packet data network connection is no longer available, transferring the at least one packet data network connection from the network function instance to another network function instance included in the network function set.

[0026] The transferring may include initiating a transfer of the at least one packet data network connection from the network function instance to another network function instance included in the network function set.

[0027] The transferring may include receiving a transfer request of at least one packet data network connection from the network function instance to another network function instance included in the network function set.

[0028] The information regarding the identification of the network capability set may be received during one of a packet data network connection establishment and an inter-system mobility of the packet data connection.

[0029] The method may include, in response to receiving an indication that a network function instance is no longer available, maintaining a context of at least one packet data network connection, and transferring the at least one packet data network connection to another network function instance included in the network function set.

[0030] The context of at least one packet data network connection may include at least one of the following: an international mobile subscriber identity, an international mobile equipment identity, a globally unique temporary identity, an access point name, a packet data gateway identifier, a packet data gateway Internet Protocol address of an S5 or S8 interface, a packet data gateway tunnel endpoint identifier of an S5 or S8 interface, a mobility management entity Internet Protocol address of an S11 interface, a mobility management entity tunnel endpoint identifier of an S11 interface, and a serving gateway Internet Protocol address of an S11 interface.

[0031] The method may include providing a session request message to the network function instance during establishment of the packet data network connection, the session request message including an indication that the apparatus supports transfer of the packet data network connection from one network function instance to another network function instance in the set of network functions.

[0032] The method may include providing a mobility bearer request message to a network function instance during inter-system mobility of a packet data connection, the mobility bearer request message including an indication that the apparatus supports transfer of the packet data network connection from one network function instance to another network function instance in a network function set.

[0033] The method may include selecting, for at least one packet data network connection, another network function instance of the network function set to be transferred to based on the received information about the identification of the network function set.

[0034] The method may include receiving an indication that another network function instance has been selected for at least one packet data network connection.

[0035] The method may include, when transferring at least one packet data network connection to another network function instance, providing a message to the other network function instance, the message including an identification of a user subscription or user equipment associated with the at least one packet data network connection, and information about a default bearer for the at least one packet data network connection.

[0036] The method may include receiving information about another network function instance to which at least one packet data network connection is being transferred.

[0037] The component may also be configured to perform: receiving information about another network function instance, the information including a fully qualified domain name of the another network function instance.

[0038] The information about the other network function instance may include an Internet Protocol address and a control plane identifier of a General Packet Radio Service Tunneling Protocol control plane tunnel for the packet data network connection at the other network function instance.

[0039] At least one of the network function instance and the other network function instance may include a session management function / packet data network gateway control plane SMF / PGW-c instance.

[0040] The information about the identification of the network capability set may be included in one of the create session response message and the modify bearer response message.

[0041] The information about the identification of the network capability set may include a domain name of the network capability set.

[0042] The information about the identity of the network capabilities set includes a fully qualified domain name of the network capabilities set.

[0043] The network function instance may no longer be available due to at least one of a failure, a restart, and a scale-in.

[0044] An indication that the network function instance is unavailable is received in a gateway restart notification message.

[0045] The method may include notifying a home subscriber server that at least one packet data network connection has been transferred from a network function instance to another network function instance, enabling the home subscriber server to update stored information about the at least one packet data network connection.

[0046] The method may be performed by one of a mobility management entity and a serving gateway entity.

[0047] According to one aspect, an apparatus is provided that includes means for providing information regarding an identification of a network capability set associated with at least one packet data network connection.

[0048] The component may also be configured to perform: providing an indication that a network function instance of the network function set is no longer available, enabling at least one packet data network connection to be transferred from the network function instance to another network function instance included in the network function set.

[0049] The identifier of the network capability set may include a fully qualified domain name.

[0050] The component may also be configured to perform: providing an echo request to a mobility management entity.

[0051] The component may also be configured to perform: providing an echo request including the incremented restart counter to the serving gateway.

[0052] The component may also be configured to perform: providing an echo request including a new restart counter to the serving gateway.

[0053] The apparatus may be comprised in a packet data gateway.

[0054] The apparatus may include a packet data network gateway instance.

[0055] According to one aspect, an apparatus is provided that includes components for: receiving a request to transfer at least one packet data network connection from a network function instance within a network function set to another network function instance included in the network function set; and providing an indication that at least one packet data network connection has been transferred to the other network function instance, the indication including information about an identification of the other network function instance.

[0056] The component may also be configured to perform: providing information about another network function instance, the information including a fully qualified domain name of the another network function instance.

[0057] The information about the other network function instance may include an Internet Protocol address and a control plane identifier of a General Packet Radio Service Tunneling Protocol control plane tunnel for at least one packet data network connection at the other network function instance.

[0058] The component may also be configured to perform: receiving context data of a user subscriber or user equipment of at least one packet data network connection.

[0059] The apparatus may be comprised in a packet data gateway.

[0060] The apparatus may be included within a packet data network gateway instance.

[0061] According to another aspect, a method is provided, the method comprising providing information regarding an identification of a network capability set associated with at least one packet data network connection.

[0062] The method may include providing an indication that a network function instance of the network function set is no longer available, enabling at least one packet data network connection to be transferred from the network function instance to another network function instance included in the network function set.

[0063] The identifier of the network capability set may include a fully qualified domain name.

[0064] The method may include providing an echo request to a mobility management entity.

[0065] The method may include providing an echo request including an incremented restart counter to a serving gateway.

[0066] The method may include providing an echo request including a new restart counter to a serving gateway.

[0067] The method may be performed by a packet data network gateway instance.

[0068] According to another aspect, a method is provided, the method comprising: receiving a request to transfer at least one packet data network connection from a network function instance within a network function set to another network function instance included in the network function set; and providing an indication that at least one packet data network connection has been transferred to the other network function instance, the indication comprising information about an identification of the other network function instance.

[0069] The method may include providing information about another network function instance, the information including a fully qualified domain name of the another network function instance.

[0070] The information about the other network function instance may include an Internet Protocol address and a control plane identifier of a General Packet Radio Service Tunneling Protocol control plane tunnel for at least one packet data network connection at the other network function instance.

[0071] The method may comprise receiving context data of a user subscriber or user equipment of at least one packet data network connection.

[0072] The method may be performed by a packet data network gateway instance.

[0073] According to another aspect, a set is provided, the device comprising: a first device, comprising a component for providing information about the identification of a network function set associated with at least one packet data network connection; a second device, comprising a component for the following operations: receiving a request to transfer at least one packet data network connection from a network function instance within the network function set to another network function instance included in the network function set; and providing an indication that at least one packet data network connection has been transferred to another network function instance, the indication comprising information about the identification of the other network function instance.

[0074] At least one of the set, the first device, and the second device may be included in a packet data gateway.

[0075] According to another aspect, an apparatus is provided, comprising: at least one processor; and at least one memory comprising computer program code, the at least one memory and the computer program code being configured to, together with the at least one processor, cause the apparatus to at least perform: receiving information about an identification of a network function set associated with at least one packet data network connection; and in response to receiving an indication that a network function instance of the network function set supporting at least one packet data network connection is no longer available, transferring at least one packet data network connection from the network function instance to another network function instance included in the network function set.

[0076] The at least one memory and the computer program code may be configured to, with the at least one processor, cause the apparatus to at least perform: initiating transfer of at least one packet data network connection from a network function instance to another network function instance included in the network function set.

[0077] The at least one memory and the computer program code may be configured to, with the at least one processor, cause the apparatus to at least perform: receiving a transfer request of at least one packet data network connection from a network function instance to another network function instance included in the network function set.

[0078] The information regarding the identification of the network capability set may be received during one of a packet data network connection establishment and an inter-system mobility of the packet data connection.

[0079] The at least one memory and the computer program code may be configured to, with the at least one processor, cause the apparatus to at least perform: in response to receiving an indication that a network function instance is no longer available, maintaining a context of at least one packet data network connection, and transferring at least one packet data network connection to another network function instance included in the network function set.

[0080] The context of at least one packet data network connection may include at least one of the following: an international mobile subscriber identity, an international mobile equipment identity, a globally unique temporary identity, an access point name, a packet data gateway identifier, a packet data gateway Internet Protocol address of an S5 or S8 interface, a packet data gateway tunnel endpoint identifier of an S5 or S8 interface, a mobility management entity Internet Protocol address of an S11 interface, a mobility management entity tunnel endpoint identifier of an S11 interface, and a serving gateway Internet Protocol address of an S11 interface.

[0081] The at least one memory and the computer program code may be configured to, with the at least one processor, cause the apparatus to at least perform: providing a session request message to a network function instance during establishment of a packet data network connection, the session request message comprising an indication that the apparatus supports transfer of the packet data network connection from one network function instance to another network function instance in a set of network functions.

[0082] The at least one memory and the computer program code may be configured to, with the at least one processor, cause the apparatus to at least perform: providing a mobility bearer request message to a network function instance during inter-system mobility of a packet data connection, the mobility bearer request message comprising an indication that the apparatus supports transfer of the packet data network connection from one network function instance to another network function instance in a network function set.

[0083] The at least one memory and the computer program code may be configured to, with the at least one processor, cause the apparatus to at least perform: selecting, for at least one packet data network connection, another network function instance of the network function set to be transferred to based on the received information about the identification of the network function set.

[0084] The at least one memory and the computer program code may be configured to, with the at least one processor, cause the apparatus to at least perform: receiving an indication that another network function instance has been selected for at least one packet data network connection.

[0085] The at least one memory and the computer program code may be configured to, together with the at least one processor, cause the apparatus to at least perform: when transferring at least one packet data network connection to another network function instance, provide a message to the other network function instance, the message comprising an identification of a user subscription or user equipment associated with the at least one packet data network connection, and information about a default bearer for the at least one packet data network connection.

[0086] The at least one memory and the computer program code may be configured to, with the at least one processor, cause the apparatus to at least perform: receiving information about another network function instance to which at least one packet data network connection is being transferred.

[0087] The at least one memory and the computer program code may be configured to, with the at least one processor, cause the apparatus to at least perform: receiving information about another network function instance, the information comprising a fully qualified domain name of the another network function instance.

[0088] The information about the other network function instance may include an Internet Protocol address and a control plane identifier of a General Packet Radio Service Tunneling Protocol control plane tunnel for the packet data network connection at the other network function instance.

[0089] At least one of the network function instance and the other network function instance may include a session management function / packet data network gateway control plane SMF / PGW-c instance.

[0090] The information about the identification of the network capability set may be included in one of the create session response message and the modify bearer response message.

[0091] The information about the identification of the network capability set may include a domain name of the network capability set.

[0092] The information about the identity of the network capabilities set includes a fully qualified domain name of the network capabilities set.

[0093] The network function instance may no longer be available due to at least one of a failure, a restart, and a scale-in.

[0094] An indication that the network function instance is unavailable is received in a gateway restart notification message.

[0095] The at least one memory and the computer program code may be configured to, with the at least one processor, cause the apparatus to at least perform: notifying a home subscriber server that at least one packet data network connection has been transferred from a network function instance to another network function instance, so that the home subscriber server can update stored information about the at least one packet data network connection.

[0096] The apparatus may be included in one of a mobility management entity and a serving gateway entity.

[0097] According to another aspect, an apparatus is provided, comprising: at least one processor; and at least one memory comprising computer program code, the at least one memory and the computer program code being configured to, together with the at least one processor, cause the apparatus to at least perform: providing information about an identification of a network function set associated with at least one packet data network connection.

[0098] The at least one memory and the computer program code may be configured to, together with the at least one processor, cause the apparatus to at least perform: providing an indication that a network function instance of a network function set is no longer available, so that at least one packet data network connection can be transferred from the network function instance to another network function instance included in the network function set.

[0099] The identifier of the network capability set may include a fully qualified domain name.

[0100] The at least one memory and the computer program code may be configured to, with the at least one processor, cause the apparatus to at least perform: providing an echo request to a mobility management entity.

[0101] The at least one memory and the computer program code may be configured to, with the at least one processor, cause the apparatus to at least perform: providing an echo request including an incremented restart counter to a serving gateway.

[0102] The at least one memory and the computer program code may be configured to, with the at least one processor, cause the apparatus to at least perform: providing an echo request including a new restart counter to a serving gateway.

[0103] The apparatus may be comprised in a packet data gateway.

[0104] The apparatus may be included within a packet data network gateway instance.

[0105] According to another aspect, an apparatus is provided, comprising: at least one processor; and at least one memory comprising computer program code, the at least one memory and the computer program code being configured to, together with the at least one processor, cause the apparatus to at least perform: receiving a request to transfer at least one packet data network connection from a network function instance within a network function set to another network function instance included in the network function set; and providing an indication that at least one packet data network connection has been transferred to another network function instance, the indication comprising information about an identification of the other network function instance.

[0106] The at least one memory and the computer program code may be configured to, with the at least one processor, cause the apparatus to at least perform: providing information about another network function instance, the information comprising a fully qualified domain name of the another network function instance.

[0107] The information about the other network function instance may include an Internet Protocol address and a control plane identifier of a General Packet Radio Service Tunneling Protocol control plane tunnel for at least one packet data network connection at the other network function instance.

[0108] The at least one memory and the computer program code may be configured to, with the at least one processor, cause the apparatus to at least perform: receiving context data of a user subscriber or user equipment of at least one packet data network connection.

[0109] The apparatus may be comprised in a packet data gateway.

[0110] The apparatus may be included within a packet data network gateway instance.

[0111] According to another aspect, a computer program comprising computer executable instructions is provided that, when executed on one or more processors, performs: receiving information about an identification of a network function set associated with at least one packet data network connection; and in response to receiving an indication that a network function instance of the network function set supporting the at least one packet data network connection is no longer available, transferring the at least one packet data network connection from the network function instance to another network function instance included in the network function set.

[0112] According to another aspect, there is provided a computer program comprising computer executable instructions which, when executed on one or more processors, performs: providing information about an identification of a network capability set associated with at least one packet data network connection.

[0113] According to another aspect, a computer program comprising computer executable instructions is provided, which, when executed on one or more processors, performs: receiving a request to transfer at least one packet data network connection from a network function instance within a network function set to another network function instance included in the network function set; and providing an indication that at least one packet data network connection has been transferred to the other network function instance, the indication comprising information about an identification of the other network function instance.

[0114] A computer product stored on a medium may cause an apparatus to perform a method as described herein.

[0115] An electronic device may comprise an apparatus as described herein.

[0116] In the above, various aspects have been described. It should be understood that other aspects can be provided by combining any two or more of the above various aspects.

[0117] Various other aspects and further embodiments are also described in the following detailed description and appended claims.

[0118] According to some aspects, the subject matter of the independent claims is provided. Some other aspects are defined in the dependent claims. Embodiments not falling within the scope of the claims are to be construed as examples useful for understanding the present disclosure.

[0119] List of abbreviations:

[0120] AF Application Function

[0121] AUSF authentication server function

[0122] AMF Access and Mobility Management Function

[0123] BS Base Station

[0124] DN Data Network

[0125] eNB eNodeB

[0126] gNB gNodeB

[0127] HSS Home Subscriber Server

[0128] LTE Long Term Evolution

[0129] MME Mobility Management Entity

[0130] NEF Network Exposure Function

[0131] NF Network Function

[0132] NR New Radio

[0133] NRF Network Repository Features

[0134] MS Mobile Station

[0135] PDN Packet Data Network

[0136] PDU Protocol Data Unit

[0137] PGW Packet Data Network Gateway

[0138] PLMN Public Land Mobile Network

[0139] QoS Quality of Service

[0140] RAN Radio Access Network

[0141] RF

[0142] SGW Service Gateway

[0143] SMF session management functions

[0144] UE User Equipment

[0145] UDSF unstructured data storage function

[0146] UDM Unified Data Management

[0147] 3GPP Third Generation Partnership Project

[0148] 5G Fifth Generation

[0149] 5GC 5G Core Network

[0150] 5G-AN 5G Access Network

[0151] 5GS 5G System BRIEF DESCRIPTION OF THE DRAWINGS

[0152] Embodiments will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0153] Figure 1 A schematic diagram of a 5G system is shown;

[0154] Figure 2 shows a schematic diagram of the control device;

[0155] Figure 3 shows a schematic diagram of a terminal;

[0156] Figure 4 shows a schematic diagram of a 4G system;

[0157] Figure 5 A schematic diagram showing the interaction between EPS and 5G system;

[0158] Figure 6 A schematic diagram showing the connection between user equipment and network functions;

[0159] Figure 7 shows an example signaling diagram between network entities;

[0160] Figure 8 Another example signaling diagram between network entities is shown;

[0161] Fig. 9 Another example signaling diagram between network entities is shown;

[0162] Fig.10 Another example signaling diagram between network entities is shown;

[0163] Fig.11 Another example signaling diagram between network entities is shown;

[0164] Fig.12 Example method steps performed by a first network entity are shown;

[0165] Fig.13 Example method steps performed by a second network entity are shown;

[0166] Fig.14 Example method steps performed by a second network entity are shown; and

[0167] Fig.15 A schematic diagram of a non-volatile storage medium storing instructions that, when executed by a processor, allow the processor to perform Figure 12 to Figure 14 One or more of the steps of the method. DETAILED DESCRIPTION

[0168] Before explaining some examples of the present disclosure in detail, Figures 1 to 3 Certain general principles of wireless communication systems and mobile communication devices are briefly explained to aid understanding of the underlying technology of the described examples.

[0169] In such Figure 1In the wireless communication system 100 shown, a mobile communication device / terminal or user equipment and / or user equipment (UE) and / or machine type communication device 102 is provided with wireless access via at least one base station (not shown) or similar wireless transmission and / or reception node or point. The communication device is provided with appropriate signal reception and transmission means to enable communication, such as access to a communication network or direct communication with other devices. The communication device can access a carrier provided by a station or access point and transmit and / or receive communications on the carrier.

[0170] In the following, certain examples are explained with reference to a mobile communication device capable of communicating via a wireless cellular system and a mobile communication system serving such a mobile communication device. Figure 1 , Figure 2 and Figure 3 Certain general principles of wireless communication systems, their access systems and mobile communication devices are briefly explained to help understand the technology underlying the described examples.

[0171] Figure 1 A schematic diagram of a 5G system (5GS) 100 is shown. The 5GS may include a terminal 102, an access network (AN) 106, a 5G core network (5GC) 104, one or more network functions (NFs), one or more application functions (AFs) 108, and one or more data networks (DNs) 110.

[0172] 5G-AN 106 may include one or more gNodeB (gNB) distributed unit functions connected to one or more gNodeB (gNB) centralized unit functions. 5G-AN may also include other forms of access networks, such as non-3GPP interworking functions (N3IWF), trusted non-3GPP gateway functions (TNGF), or wired access gateway functions (W-AGF) (connected to wired access).

[0173] 5GC 104 may include access and mobility management function (AMF) 112, session management function (SMF) 114, authentication server function (AUSF) 116, user data management (UDM) 118, user plane function (UPF) 120, network exposure function (NEF) 122 and / or other NFs. 5GS may also include a policy control function (PCF) not shown. Some of the examples shown below may be applicable to the 3GPP 5G standard. However, some examples may also be applicable to 4G, 3G and other 3GPP standards.

[0174] In such Figure 1In the communication system shown, a mobile communication device / terminal or user equipment and / or user equipment (UE) and / or machine type communication device is provided with wireless access via at least one base station or similar wireless transmission and / or reception node or point. The terminal is provided with appropriate signal reception and transmission devices to enable communication, such as access to a communication network or direct communication with other devices. The communication device can access a carrier provided by a station or access point and transmit and / or receive communications on the carrier.

[0175] Figure 2 shows the control method for Figure 1 An example of a control device 200 for the functions of a 5G-AN or 5GC shown. The control device may include at least one random access memory (RAM) 211a, at least one read-only memory (ROM) 211b, at least one processor 212, 213, and an input / output interface 214. At least one processor 212, 213 may be coupled to the RAM 211a and the ROM 211b. At least one processor 212, 213 may be configured to execute appropriate software code 215. The software code 215 may, for example, allow one or more steps to be executed to perform one or more of the present aspects. The software code 215 may be stored in the ROM 211b. The control device 200 may be interconnected with another control device 200 that controls another function of a 5G-AN or 5GC. In some examples, the functions of the 5G-AN and / or 5GC include the control device 200. In an alternative example, two or more functions of the 5G-AN or 5GC may share a control device.

[0176] Figure 3 An example of a terminal 300 is shown, such as Figure 1 The terminal shown. The terminal 300 can be provided by any device capable of sending and receiving radio signals. Non-limiting examples include user equipment, a mobile station (MS) or a mobile device (such as a mobile phone or a so-called "smart phone", etc.), a computer provided with a wireless interface card or other wireless interface facilities (e.g., a USB dongle), a personal data assistant (PDA) or a tablet computer provided with wireless communication capabilities, a machine type communication (MTC) device, a cellular Internet of Things (CIoT) device, or any combination of these devices, etc. The terminal 300 can provide, for example, data communication for bearer communication. The communication can be one or more of voice, email (email), text message, multimedia, data, machine data, etc.

[0177] The terminal 300 may receive signals over the air or radio interface 307 via suitable means for reception, and may transmit signals via suitable means for transmission of radio signals. Figure 3In the mobile device, the transceiver arrangement is schematically represented by a block 306. The transceiver arrangement 306 may be provided, for example, by means of a radio part and an associated antenna arrangement. The antenna arrangement may be arranged internally or externally to the mobile device.

[0178] The terminal 300 may be provided with at least one processor 301, at least one memory ROM 302a, at least one RAM 302b and other possible components 303 for use in the software and hardware assisted execution of the tasks it is designed to perform, including control of access to and communication with access systems and other communication devices. The at least one processor 301 is coupled to the RAM 302a and the ROM 302b. The at least one processor 301 may be configured to execute appropriate software code 308. The software code 308 may, for example, allow one or more of the aspects to be performed. The software code 308 may be stored in the ROM 302b.

[0179] The processor, storage means and other related control means may be provided on an appropriate circuit board and / or in a chipset. This feature is indicated by reference numeral 304. The device may optionally have a user interface, such as a keypad 305, a touch-sensitive screen or keyboard, a combination thereof, etc. Optionally, one or more of a display, a speaker and a microphone may be provided depending on the type of device.

[0180] Some of the example embodiments shown below may be applicable to both 3GPP 4G and 5G standards. However, some example embodiments may also be applicable to 3G and other 3GPP standards.

[0181] It has been proposed to have a control and user plane separation. This can enable flexible network deployment and operation through distributed or centralized deployment. This can provide independent scaling between control plane functions and user plane functions while not affecting the functionality of existing nodes affected by the split.

[0182] Control and User Plane Separation (CUPS) of Evolved Packet Core (EPC) nodes was introduced in 4G. CUPS is an architectural enhancement feature that introduces the concept of separation between the control plane and the user plane of EPC nodes, such as S-GW (Serving Gateway), P-GW (Packet Data Network), and T-DF (Traffic Detection Function).

[0183] This example architecture of a 4G system with CUPS is Figure 4 Shown in.

[0184] The architecture shows a base station 401 (such as an evolved Node B eNB) that can communicate with a mobile mobility management entity (MME) 403. The base station 401 can communicate with one or more user equipments (UEs) (not shown). The MME 403 can communicate with a control plane serving gateway 405 (SGW-C) function, which in turn can communicate with a control plane packet data network gateway 407 (PGW-C) function and a user plane serving gateway function 409 (SGW-U). The SGW-U function 409 is also connected to a user plane packet data network gateway function 411 (PGW-U). The PGW-C function 407 can communicate with the PGW-U 411 function.

[0185] Therefore, if Figure 4 As shown, MME 403, SGW-C and PGW-C constitute the control plane function, while eNB 401, SGW-U 409 and PGW-U 411 constitute the user plane function. eNB 401 may include both the user plane function and the control plane function.

[0186] In Release 16 5G Core Network, from the perspective of 3GPP functions, a Session Management Function (SMF) set may include a set of equivalent and interchangeable SMF instances. SMF sets may share the same (packet data unit session) context data. SMF sets may provide distribution, redundancy, and scalability when acting together as a set of SMF instances.

[0187] Figure 5 The architecture supporting inter-system mobility between the Evolved Packet System (EPS) and the 5G System (5GS) is schematically shown. For EPS interworking, the SMF 501 is co-located with the Packet Data Network (PDN) Gateway Control Plane (PGW-c). PGW-c represents the control plane portion of the PGW. In some of the following examples, the SMF located together with the PGW-c may be labeled as SMF / PGW-c. SMF / PGW-c is a combined network entity that acts as the SMF for a 5GC peer and as the PGW-c for an EPC peer. This allows data connections (PDU sessions / PDN connections) to move between the EPC and the 5GC. The N26 interface can be supported between the Mobility Management Entity (MME) 503 and the Access and Mobility Management Function (AMF) 505 to achieve inter-system mobility.

[0188] exist Figure 5On the EPS side of the UE 507, the UE 507 is connected to the Evolved UMTS Terrestrial Radio Access Network (E-UTRAN) 509. The E-UTRAN 509 is connected to the MME 503. The MME 503 is connected to the Serving Gateway (SGW) 511 via the S11 interface. The MME 503 is also connected to the Home Subscriber Server / Unified Data Management HSS / UDM 521 via the S6a interface. The SGW 511 is connected to the SMF / PGW-c 501 via the S5-C interface. The SGW 511 is also connected to the UPF / PGW-u 513 via the S5-U interface.

[0189] On the 5GS side, another UE 515 is connected to the Next Generation Radio Access Network (NG-RAN) 517. The other UE 515 is also connected to the AMF 505 via the N1 interface. The NG-RAN 517 is also connected to the AMF 505 via the N2 interface. The NG-RAN 517 is connected to the UPF / PGW-u 513 via the N3 interface. The AMF 505 is connected to the SMF / PGW-c 501 via the N11 interface. The AMF 505 is also connected to the Policy Control Function (PCF) 519. The AMF 505 is also connected to the HSS / UDM 521 via the N8 interface.

[0190] UPF / PGW-u 513 is connected to SMF / PGW-c 501 via N4 interface. SMF / PGW-c 501 is connected to PCF 519 via N7 interface. SMF / PGW-c 501 is connected to HSS / UDM 521 via N10 interface.

[0191] In the current system, there is no concept of PGW-c set in EPC. SGW can notify MME of PGW failure or restart by sending PGW restart notification to MME. In this case, MME releases the PDN connection supported by the PGW and requests UE to reestablish sensitive packet data network (PDN) connection. An example of sensitive PDN connection is Internet Protocol Multimedia System (IMS) connection. The release of PDN connection causes a lot of signaling on the radio interface in the access network and core network.

[0192] Current systems for inter-system mobility between EPS and 5GS that rely on SMF / PGW-c combinations may not be suitable for the SMF Set concept. It may not be possible to extend the SMF Set inwards without tearing down and re-establishing the PDN connection of the SMF / PGW-c. In this context, extending the SMF Set inwards is the same as removing the SMF / PGW-c instances. In addition, if one or more of the SMF / PGW-c instances fail, the MME cannot reselect a different SMF / PGW-c from the set of SMF / PGW-c instances for the ongoing PDN connection. If the SMF / PGW-c instance were to fail, the PDN connection would be lost and would need to be re-established.

[0193] Questions such as Figure 6 shown. Figure 6 The EPS is shown to include a UE 601 and an MME 603. The 5GS includes a further UE 605 and an AMF 607. The SMF set 609 includes four SMF / PGW-c instances 611a to 611d. The SMF set 609 is accessible by both the EPS and the 5GS. The SMF set 609 is associated with an unstructured data storage function 613. A Home Subscriber Server / Unified Data Management 615 is also provided.

[0194] Figure 6 It shows a PDN connection between another UE 605 and SMF set 609. There is a PDN connection between UE 601 and SMF / PGW-c which has been disconnected.

[0195] SMF / PGW-c 611a to 611d instances can be accessed via 5GS or EPS to establish PDU sessions (5GS) and PDN connections (EPS). In 5GS, network functions that interact with SMF can utilize the SMF set concept. If one of the SMF instances fails or cannot access the ongoing PDU session for any reason, the network function can reselect another SMF instance from the SMF set 609. Some examples of where an SMF instance may fail include temporary network failures, overloads, and SMF instances being de-instantiated during inbound expansion operations. After reselection, normal operations can be performed on the relevant PDU sessions.

[0196] However, this situation is different from the case of a PDN connection using EPS, or the case where a PDU session established over 5GS becomes a PDN connection when the UE has moved into EPS coverage. According to current network specifications, if one SMF / PGW-c fails, the MME cannot reselect a different SMF / PGW-c from the set for the ongoing PDN connection. The PDN connection is lost and needs to be reestablished. In addition, if the SMF / PGW-c instance is de-instantiated, the MME cannot reselect a different SMF / PGW-c from the set for the ongoing PDN connection. This is in Figure 6 , where in 5GS, there is a PDN connection between another UE 605 and the SMF set 609. If one of the SMF / PGW-c 611a to 611d instances fails or is inaccessible, the AMF can reselect another SMF / PGW-c 611a to 611d within the set 609. A PDN connection between a UE 601 and SMF / PGW-c 611b in EPS is shown. If the SMF / PGW-c 611b instance fails, is extended inward, or is inaccessible, the PDN connection will be lost. The PDN connection will be lost and needs to be reestablished.

[0197] The following examples and embodiments are directed to addressing one or more of the above issues.

[0198] As described above, if one SMF / PGW-c fails, becomes inaccessible or is de-instantiated, the MME cannot reselect a different SMF / PGW-c instance from the set of SMF / PGW-c instances for the ongoing PDN connection.

[0199] Some examples propose enhancements to the General Packet Radio Service (GPRS) Tunneling Protocol Control (GTP-C) protocol and the EPC recovery process. Some examples enable the PGW-c to signal the PGW set fully qualified domain name (FQDN) to the SGW / MME during PDN connection establishment or during the mobility of a PDU session from the 5GC to the EPC. When the PGW-c becomes unavailable, the MME does not tear down the PDN connection supported by the PGW-C, but reselects a new SMF / PGW-c instance from the set based on the PGW set FQDN. This will be described in more detail below.

[0200] Before discussing these examples and embodiments, Figures 7 to 9 Discuss some potential alternative solutions together.

[0201] Figure 7An example signaling diagram between MME, SGW, and the first and second PGWs is shown. For SMF / PGW-c, there is a standby SMF / PGW-c. The standby SMF / PGW-c takes over the control of the PDN connection when PGW-c fails / inward expansion occurs.

[0202] At S701 , the MME transmits a create session request to PGW A via the SGW.

[0203] At S702 , PGW A transmits a create session response message to MME via SGW.

[0204] At S703 , a failure, inward expansion, or restart of PGW A occurs.

[0205] In S704, the MME transmits a bearer modification request to the standby SMF / PGW-c and PGW B via the SGW.

[0206] At S705 , PGW B transmits a modify bearer response message to MME via SGW.

[0207] Some of the disadvantages of this mechanism are that deploying geographically redundant PGW-c for each PGW-c in the public land mobile network may incur significant operational expenses. In addition, it does not take advantage of the SMF set concept in 5GS. SMF sets can enable cheaper redundancy schemes where there is no need to deploy duplicate signaling resources for redundancy, such as Figure 7 In addition, this mechanism does not support preserving PDN connections during inbound extension of PGW-c.

[0208] Figure 8 An example signaling diagram between an MME, an SGW, a front end of a PGW set, and a first PGW and a second PGW of the PGW set is shown. The PGW set supports a front end GPRS Tunneling Protocol Control Plane (GTP-C) relay.

[0209] At S801 , the MME transmits a create session request to PGW A via the SGW and the front-end relay.

[0210] At S802, PGW A transmits a create session response message to MME via SGW. PGW A may also transmit a fully qualified tunnel endpoint identifier (eg, IP address and TEID of PGW A) and a front-end IP address to SGW / MME via S5 / S8.

[0211] At S803, a failure, inward expansion, or restart of PGW A occurs.

[0212] At S804, the MME transmits a modify bearer request via the SGW. This may take the IP address of the front end as transmitted by the PGWA in the fully qualified TEID. The front end forwards the request to the standby PGW B.

[0213] At S805 , PGW B transmits a modify bearer response message to MME via SGW.

[0214] The front-end entity forwards the request to the back-end entity which processes the request. The back-end entity can scale inwards, fail, and restart transparently to the MME / SGW. Redundant front-end entities are required which support moving the IP address of one front-end to another in case of a front-end failure. This is transparent to the MME and SGW.

[0215] Some of the disadvantages of this mechanism are that this requires the deployment of a new front-end entity in the existing EPC. In addition, the front-end must handle the GTP-c traffic of the SMF / PGW-c cluster, which may have high signaling costs. In addition, the front-end must be replicated using floating IP addresses and the association between the fully qualified tunnel endpoint identifier control plane (F-TEID-c) and the SMF / PGW-c instance must be maintained (stateful), which has signaling costs.

[0216] Fig. 9 An example signaling diagram is shown between the MME, SGW, and the first PGW and the second PGW of the PGW set. If a PGW fails or is extended inward, the PGW-cF-TEID will be taken over by another PGW. In this case, being taken over means that the F-TEID is taken over by another PGW. This is transparent to the MME and / or SGW.

[0217] At S901 , the MME transmits a create session request to PGW A via the SGW.

[0218] At S902, PGW A transmits a create session response message to MME via SGW. The create session response message may include a PGW fully qualified tunnel endpoint identifier (F-TEID).

[0219] At S903 , a failure, inward expansion, or restart of PGW A occurs.

[0220] In S904, the MME transmits a bearer modification request to the standby SMF / PGW-c and PGW B via the SGW.

[0221] At S905 , PGW B transmits a modify bearer response message to MME via SGW.

[0222] Some of the disadvantages of this mechanism are that the set of PGWs may span different subnets or even data centers to support geographic redundancy. In addition, this mechanism may utilize Border Gateway Protocol (BGP) or another protocol that may take an unacceptable amount of time for the network to converge. The PDN connection of a failed / inbound PGW may need to be taken over by another PGW of the same, which may not be possible or cause the new PGW to be overloaded.

[0223] As described above, some examples enable the PGW-c to signal the PGW set fully qualified domain name (FQDN) to the SGW / MME during PDN connection establishment. This can also occur during the mobility of the PDU session from the 5GC to the EPC. When the PGW-c becomes unavailable, the MME does not tear down the PDN connection supported by the PGW-c. In some examples, the MME can reselect a new SMF / PGW-c instance from the set based on the PGW set FQDN. In these examples, the MME supports the transfer of a PDN connection from one PGW instance to another PGW instance.

[0224] Fig.10 An example signaling diagram between network entities is shown. In this example, communication occurs between an MME, an SGW, an HSS, a first network function instance (labeled "PGW A"), and a second network function (labeled "PGW B"). The first network function instance and the second network function instance may be part of a network function set. In this example, PGW A depicts a PGW-c that will fail, disconnect, or be extended inward. In this example, PGW B depicts a PGW-c within a PGW-c set that will be selected to take over to provide services for a PDN connection that was once served by PGW-A. The first network function instance and the second network function instance may be SMF / PGW-c instances. In other examples, the first network function instance and the second network function instance may be PGW-c instances. In other examples, one or more entities may not participate in the communication. In other examples, one or more additional entities may participate in the communication. A user equipment (UE) may be associated with an MME. A user subscriber may be associated with an MME. The UE may maintain a PDN connection context associated with a network function instance that is part of a set. In the following notations, an SMF / PGW-c set may be referred to as a PGW set.

[0225] At S1001, the MME provides a request message to the SGW. The request message may be, for example, a create session request message. The SGW forwards the request message to PGW A. The SGW forwards the request message to PGW A using the IP address indicated by the MME. When the MME provides the request message, the MME may signal a flag indicating support for the following enhancements. For example, the MME may set a flag indicating that the MME supports transferring a PDN connection from one PGW instance to another PGW instance. For example, the flag may be a "PGW Set FQDN Support Indication".

[0226] At S1002, PGW A provides a response message to the SGW. The response message may be, for example, a create session response message. The response message may include information about the identity of the PGW set. In one example, the information about the identity of the PGW set may include the domain name of the PGW set. In another example, the response message may include the PGW set FQDN. As discussed in S1001, when the MME has signaled a flag indicating support for enhancement, the response message may include information about the identity of the PGW set. The SGW then forwards the response message to the MME.

[0227] At S1003a, PGW A is shut down due to a restart. In other examples, PGW A is shut down due to a failure. PGW A may be shut down for any suitable reason.

[0228] At S1003b, PGW A is de-instantiated. PGW A may be de-instantiated due to, for example, an inward extension scenario.

[0229] At S1004, if PGW A is de-instantiated, the access point name (APN) related domain name server (DNS) record is updated to remove PGW A. The DNS record can be updated by the operation, administration and maintenance (OAM) entity. PGW A can provide an echo request to the SGW. The echo request is a GTP-u type message. The echo request may include an incremented restart counter. If PGW A is de-instantiated, the echo request may include a new restart timer instead. In other examples, instead of receiving the echo request at the SGW, the SGW detects the absence of an acknowledgment of the PGW A answer. For example, the absence of a response to the echo request message received by PGW A.

[0230] At S1005, when the SGW has detected that PGW A has failed / restarted / de-instantiated, the SGW provides a restart notification to the MME. The SGW may have detected that PGW A has failed / restarted / de-instantiated due to the reception of an echo request message. In other examples, the SGW may have detected that PGW A has failed / restarted / de-instantiated due to the lack of a response from PGW A. If PGW A has failed / restarted / de-instantiated, the PGW may be considered to be no longer available to maintain the PDN connection. The restart notification may be, for example, a PGW restart notification. In one example, when the MME receives a notification that PGW A is no longer available and the MME has received an identifier of a PGW set for the PDN connection, the MME maintains the PDN connection context. The MME maintains the PDN connection, rather than initiating the release of the PDN connection as defined in the current 3GPP specifications. The MME may maintain the PDN connection context so that it can be transferred to be controlled by different PGWs in the set. The identifier of the PGW set may include the PGW set FQDN. In other examples, the identifier of the PGW set may include other suitable identification information. For example, the context of the PDN connection may include at least one of the following: an international mobile subscriber identity, an international mobile equipment identity, a globally unique temporary identity, an access point name, a packet data gateway identifier, a packet data gateway Internet Protocol address of the S5 or S8 interface, a packet data gateway tunnel endpoint identifier of the S5 or S8 interface, a mobility management entity Internet Protocol address of the S11 interface, a mobility management entity tunnel endpoint identifier of the S11 interface, and a serving gateway Internet Protocol address of the S11 interface.

[0231] At S1006, the MME selects a new PGW based on the received PGW set FQDN. In this example, the MME selects PGW B. PGW B may be part of the SMF / PGW-c set. The MME may perform this selection in response to receiving a restart notification from the SGW. The MME may not tear down the related PDN connections. In some examples, step S1006 may not occur immediately after step S1005.

[0232] At S1007, the MME provides information about the UE to the SGW. The SGW propagates the information to PGW-c B. The information about the UE may include a UE identity. The MME may also provide the SGW with a linked EPS bearer identifier (EBI). The EBI may identify the default EPS bearer for the PDN connection. Information about the UE and the EBI may help the new PGW-c (i.e., PGW B) find the PDN connection and take it over. In this case, taking it over means controlling the PDN connection. Information about the UE and the EBI may be included in a modify bearer request message provided to the SGW. When the corresponding signaling interaction needs to occur, the MME may immediately send a modify bearer request or send any of the aforementioned information to the PGW. The SGW may forward the information about the UE and the EBI to PGW B. In another example, the SGW may forward the modify bearer request message including information about the UE and the EBI to PGW B. In other examples, the MME may provide information about the UE and the EBI directly to PGW B.

[0233] At S1008, PGW B provides a response message to the SGW. The response message may be a modify bearer response message. The message may include identification information of PGW B. For example, the message may include a fully qualified tunnel endpoint identifier (F-TEID) of PGW B. The F-TEID may be an S5 / S8 F-TEID for the control plane of PGW B. The response message may include the name of PGW B. In some examples, the response message may include the FQDN of PGW B. PGW B may provide the PGW B F-TEID and the PGW B name / PGW B FQDN to the SGW in the response message. In other examples, PGW B may provide the PGW B F-TEID and the PGW B name / PGW B FQDN to the SGW in response to any of the aforementioned requests. However, if PGW B is to receive a delete session request, there is no need to return the PGW B F-TEID and the PGW B name / PGW B FQDN. The SGW then forwards the response message to the MME. In other examples, PGW B communicates directly with the MME.

[0234] At S1009, the MME provides the Home Subscriber Service (HSS) with the received information about the name of PGW B. This can update the PGW identity of the PDN connection in the HSS. The HSS can also update the PGW identity in the UDM of the 5GS.

[0235] At S1010, the HSS notifies the MME that the identity of the PGW has been updated. PGW B is now linked to the PDN connection.

[0236] For PDU session establishment in 5GS, the PDU session is established in 5GS as specified in the existing procedures. The AMF may also handle the SMF set as per the existing specifications. In some cases, the PDU session may be handed over to the EPC. The handover may occur with or without the N26 interface. During the mobility of the PDU session towards EPS, the PGW provides the PGW set FQDN to the MME in the Modify Bearer Response. In other examples, the PGW provides the PGW set FQDN in another suitable message type. Thereafter, the same procedures as for the PDN connection established in EPS apply, such as Fig.10 The signaling diagram is shown in FIG.

[0237] Fig.11 Another example signaling diagram between network entities is shown. If the new SMF / PGW-c instance taking over control of the PDN connection is to initiate a request towards the MME, but has not yet received a request from the MME / SGW to enable the new SMF / PGW-c instance to return the PGW-cF-TEID, as described above with respect to Fig.10 As described above, the following signaling may occur. Fig.11 In the example, communication occurs between an MME, an SGW, an HSS, a first network function instance (labeled "PGW A"), and a second network function (labeled "PGW B"). The first network function instance and the second network function instance may be part of a network function set. In this example, PGW A depicts a PGW-c that will fail, disconnect, or be extended inward. In this example, PGW-B depicts a PGW-c within the PGW-c set that will be selected to take over to provide services for the PDN connection that was once served by PGW-A. The first network function instance and the second network function instance may be SMF / PGW-c instances. In other examples, the first network function instance and the second network function instance may be PGW-c instances. In some examples, one or more entities may not participate in the communication. In other examples, one or more additional entities may participate in the communication. A user equipment (UE) may be associated with an MME. The UE may maintain a PDN connection associated with a network function instance that is part of the set. In the following notation, the SMF / PGW-c set may be referred to as a PGW set.

[0238] At S1101, the MME provides a request message to the SGW. The request message may be, for example, a create session request message. The SGW forwards the request message to PGW A. The SGW forwards the request message to PGW A using the IP address indicated by the MME. When the MME provides the request message, the MME may signal a flag indicating support for the following enhancements. For example, the flag may be a "PGW Set FQDN Support Indication".

[0239] At S1102, PGW A provides a response message to SGW. The response message may be, for example, a create session response message. SGW then forwards the response message to MME. The response message may include the PGW set FQDN. As discussed in S1101, when MME has signaled a flag indicating support for enhancement, the response message may include the PGW set FQDN.

[0240] At S1103, PGW A is shut down due to a restart. In other examples, PGW A is shut down due to a fault. In other examples, PGW A is de-instantiated. PGW A may be de-instantiated due to, for example, an inward expansion scenario. PGW A may be shut down for any suitable reason.

[0241] At S1104, if PGW A is de-instantiated / restarted / failed, the access point name (APN) related domain name server (DNS) record is updated to remove PGW A. The DNS server record may be updated by OAM. PGW A may provide an echo request to the SGW. The echo request may include an incremented restart counter. If PGW A is de-instantiated, the echo request may include a new restart timer. In other examples, instead of receiving the echo request at the SGW, the SGW detects a lack of confirmation answered by PGW A. For example, a lack of a response to an echo request message received by PGW A.

[0242] At S1105, when the SGW has detected that PGW A has failed / restarted / de-instantiated, the SGW provides a restart notification to the MME. The SGW may have detected that PGW A has failed / restarted / de-instantiated due to reception of an echo request message. In other examples, the SGW may have detected that PGW A has failed / restarted / de-instantiated due to a lack of a response from PGW A. The restart notification may be, for example, a PGW restart notification.

[0243] At S1106, another SMF / PGW-c is selected from the SMF / PGW-c for the PDN connection. Fig.11 In the example of , PGW B is selected for the PDN connection. The PCF may perform the selection. When the PCF needs to send a request for the PDN connection to the SMF, the PCF may perform the selection. In other examples, one of the UPF and PGW-u may perform the selection. In other examples, other suitable network functions may perform the selection.

[0244] At S1107, PGW B provides a request message to the SGW. The request message may be a create bearer request message. In other examples, the request message may be one of an update bearer request and a remove bearer request. The message may include identification information of PGW B. For example, the message may include a PGW B fully qualified tunnel endpoint identifier (F-TEID). The F-TEID may be an S5 / S8 F-TEID of the control plane of PGW B. The request message may include the name of PGW B. In some examples, information about the name of PGW B may include the FQDN of PGW B. PGW B may provide the PGW B F-TEID and the PGW B name / PGW B FQDN to the SGW in the request message. Then, the SGW forwards the request message to the MME. The MME may store the PGW B F-TEID and / or the PGW B name information and / or the PGW B FQDN. The SGW may also store the PGW B F-TEID and / or the PGW B name information and / or the PGW B FQDN.

[0245] At S1108, the MME provides a response message to the SGW. The response message may be a create bearer response message. The SGW then forwards the response message to PGW B. In other examples, the MME may provide a response message directly to PGW B.

[0246] At S1109, the MME provides the PGW B FQDN and / or PGW B name information to the Home Subscriber Server (HSS). This can update the PGW identity of the PDN connection in the HSS. The HSS can also update the PGW identity in the UDM of the 5GS.

[0247] At S1110, the HSS notifies the MME that the identity of the PGW has been updated. PGW B is now linked to the PDN connection.

[0248] and Fig.11 Similar examples of the signal flow shown may occur in some other examples described below.

[0249] When the MME decides not to select a new PGW-c immediately, it may happen that the PGW-u / UPF, which has detected that PGW A has failed and needs to contact the SMF / PGW-c (e.g. due to usage monitoring reports from PGW-u / UPF), selects another PGW-c in the set, such as PGW B. In this case, PGW B takes over the PDN connection from PGW A. This will be Fig.11 Another trigger of step 6 in .

[0250] The newly selected PGW B may want to inform the MME that it has taken over the PDN connection from PGW A. In this case, PGW B initiates an Update Bearer Request message to the MME, similar to Fig.11 Step S1107. The update bearer request message may provide the following information: Fully Qualified Tunnel Endpoint Identifier (F-TEID) of PGW B. The F-TEID may be the S5 / S8 F-TEID of the control plane of PGW B. The request message may include the name of PGW B. In some examples, the information about the name of PGW B may include the FQDN of PGW B. PGW B may provide the PGW B F-TEID and the PGW B name / PGWB FQDN to the SGW in the request message. The SGW then forwards the request message to the MME. The rest of the process is as above. Fig.11 As described in S1108, S1109 and S1110.

[0251] The following examples illustrate how embodiments allow inter-PLMN compatibility, while different networks (PLMNs) may have different policies on whether and when to deploy the new features. In one example, if the visited public land mobile network (VPLMN) (i.e., MME) supports the additional features as described above, but the home public land mobile network (HPLMN) (i.e., PGW) does not support the additional features, then the additional features are not applied. In this case, the behavior remains as specified in the existing specifications.

[0252] In another example, if the HPLMN (PGW) supports the additional features but the VPLMN (MME) does not support the additional features, the additional features are not applied. In this case, since the visited public land mobile network (VPLMN) ignores the new information provided by the PGW (as Fig.10 and Fig.11 ), so the behavior remains as specified in the existing specification. Upon PGW restart notification, the PDU session will be released. The PGW-C can then delete the PDN connection context. Deleting the PDN connection context can avoid hanging the context.

[0253] Some of the advantages of the examples given are that SMF / PGW-C failures and / or inbound extensions are supported without tearing down or re-establishing the UE's PDN connection in the EPC (and without radio signaling). This is achieved without deploying new entities in the EPC or geographically redundant PGWs, significantly optimizing operating expenses (OPEX). Furthermore, the concept of SMF sets of 5GS fully integrates with EPS interworking.

[0254] Fig.12An example method flow performed by an apparatus is shown. The first apparatus may be included in a network entity. The network entity may be, for example, an MME.

[0255] In S1201 , the method includes receiving information about an identification of a network capability set associated with at least one packet data network connection.

[0256] In S1203, the method includes: in response to receiving an indication that a network function instance of a network function set supporting at least one packet data network connection is no longer available, transferring at least one packet data network connection from the network function instance to another network function instance included in the network function set.

[0257] Fig.13 An example method flow performed by an apparatus is shown. The first apparatus may be included in a network entity. The network entity may be, for example, a PGW instance. In another example, the network entity may be an SMF / PGW-c instance.

[0258] In S1301 , the method includes providing information about an identification of a network capability set associated with at least one packet data network connection.

[0259] Fig.14 An example method flow performed by an apparatus is shown. The first apparatus may be included in a network entity. The network entity may be, for example, a PGW instance. In another example, the network entity may be an SMF / PGW-c instance.

[0260] In S1401 , the method includes receiving a request to transfer at least one packet data network connection from a network function instance within a network function set to another network function instance included in the network function set.

[0261] In S1403 , the method includes providing an indication that at least one packet data network connection has been transferred to another network function instance, the indication including information about an identity of the another network function instance.

[0262] Fig.15 Schematic diagram of non-volatile storage media 1500a (e.g., a computer disk (CD) or digital versatile disk (DVD)) and 1500b (e.g., a universal serial bus (USB) memory stick) storing instructions and / or parameters 1502 that, when executed by a processor, allow the processor to perform Figure 12 to Figure 14 One or more of the steps of the method.

[0263] It should be noted that while the above describes exemplifying embodiments, there are several variations and modifications which may be made to the disclosed solution without departing from the scope of the present invention.

[0264] Therefore, the examples may vary within the scope of the appended claims. In general, some embodiments may be implemented in hardware or dedicated circuits, software, logic, or any combination thereof. For example, some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software that may be executed by a controller, microprocessor, or other computing device, but the embodiments are not limited thereto. Although various embodiments may be illustrated and described as block diagrams, flow charts, or using some other graphical representations, it is well understood that, as non-limiting examples, the blocks, devices, systems, techniques, or methods described herein may be implemented in hardware, software, firmware, dedicated circuits or logic, general hardware or controllers or other computing devices, or some combination thereof.

[0265] These examples may be implemented by computer software stored in a memory and executable by at least one data processor of the entity involved, or by hardware, or by a combination of software and hardware. Further, in this regard, it should be noted that, for example, Fig.12 and Fig.13 Any process in the software may represent program steps, or interconnected logic circuits, blocks and functions, or a combination of program steps and logic circuits, blocks and functions. The software may be stored on physical media such as memory chips or memory blocks implemented within a processor, magnetic media such as hard disk or floppy disks, and optical media such as DVDs and their data variants, CDs.

[0266] The memory may be of any type suitable for the local technical environment and may be implemented using any suitable data storage technology, such as semiconductor-based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory, and removable memory. The data processor may be of any type suitable for the local technical environment and may include, as non-limiting examples, one or more of a general-purpose computer, a special-purpose computer, a microprocessor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a gate-level circuit, and a processor based on a multi-core processor architecture.

[0267] Alternatively or additionally, some examples may be implemented using a circuit system. The circuit system may be configured to perform one or more of the previously described functions and / or method steps. The circuit system may be provided in a base station and / or a communication device.

[0268] As used in this application, the term "circuitry" may refer to one or more or all of the following:

[0269] (a) pure hardware circuit implementation (such as implementation using only analog and / or digital circuit systems);

[0270] (b) A combination of hardware circuits and software, such as:

[0271] (i) a combination of analog and / or digital hardware circuits and software / firmware, and

[0272] (ii) any portion of a hardware processor(s) with software (including digital signal processor(s), software and memory(s)) that work together to enable an apparatus (such as a communication device or base station) to perform the various previously described functions; and

[0273] (c) Hardware circuit(s) and / or processor(s), such as microprocessor(s) or portion(s) of microprocessor(s), that require software (e.g., firmware) to operate, but the software may be absent when not required for operation.

[0274] This definition of circuitry applies to all uses of this term in this application, including in any claims. As another example, as used in this application, the term circuitry also covers an implementation of merely a hardware circuit or processor (or multiple processors) or a portion of a hardware circuit or processor and its accompanying software and / or firmware. The term circuitry also covers, for example, an integrated device.

[0275] The foregoing description provides a complete and informative description of some embodiments by way of exemplary and non-limiting examples. However, various modifications and adaptations may become apparent to those skilled in the relevant arts in view of the foregoing description when read in conjunction with the accompanying drawings and the appended claims. However, all such and similar modifications of these teachings will still fall within the scope defined in the appended claims.

Claims

1. A method of communication performed by a mobility management entity, comprising: receiving information regarding an identification of a network capability set associated with at least one packet data network connection; as well as In response to receiving an indication that the network function instance of the network function set supporting the at least one packet data network connection is no longer available, maintaining the context of the at least one packet data network connection, and transferring the at least one packet data network connection from the network function instance to another network function instance included in the network function set, wherein transferring the at least one packet data network connection to the another network function instance comprises providing a message to the another network function instance, the message comprising an identification of a user subscription or user equipment associated with the at least one packet data network connection and information about a default bearer for the at least one packet data network connection.

2. The method of claim 1, wherein the transferring may include: A transfer request of the at least one packet data network connection from the network function instance to another network function instance included in the set of network functions is received.

3. The method according to any one of claims 1 to 2, wherein the information about the identification of the network capability set can be received during one of: packet data network connection establishment, and inter-system mobility of a packet data connection.

4. The method of claim 1 , wherein the context of the at least one packet data network connection may include at least one of the following: an international mobile subscriber identity, an international mobile equipment identity, a globally unique temporary identity, an access point name, a packet data gateway identifier, a packet data gateway Internet Protocol address of an S5 or S8 interface, a packet data gateway tunnel endpoint identifier of an S5 or S8 interface, a mobility management entity Internet Protocol address of an S11 interface, a mobility management entity tunnel endpoint identifier of an S11 interface, and a serving gateway Internet Protocol address of an S11 interface.

5. The method according to any one of claims 1 to 2, further comprising: A session request message is provided to the network function instance during establishment of a packet data network connection, the session request message including an indication that the device supports transfer of the packet data network connection from one network function instance to another network function instance in the set of network functions.

6. The method according to any one of claims 1 to 2, further comprising: A mobility bearer request message is provided to the network function instance during inter-system mobility of a packet data connection, the mobility bearer request message including an indication that the apparatus supports transfer of a packet data network connection from one network function instance to another network function instance in the set of network functions.

7. The method according to any one of claims 1 to 2, further comprising: Based on the received information about the identification of the network function set, the other network function instance of the network function set to be transferred to is selected for the at least one packet data network connection.

8. The method according to any one of claims 1 to 2, further comprising: An indication is received that the another network function instance has been selected for the at least one packet data network connection.

9. The method according to any one of claims 1 to 2, further comprising: Information about the another network function instance to which the at least one packet data network connection is transferred is received.

10. The method of claim 9, wherein the information about the another network function instance comprises: An internet protocol address and a control plane identifier of a general packet radio service tunneling protocol control plane tunnel for the packet data network connection at the other network function instance.

11. The method according to any one of claims 1 to 2, wherein at least one of the network function instance and the another network function instance comprises: Session Management Function / Packet Data Network Gateway Control Plane SMF / PGW-c instance.

12. The method according to any one of claims 1 to 2, wherein the information about the identification of the network function set is included in one of: a create session response message, and a modify bearer response message.

13. The method according to any one of claims 1 to 2, wherein the information about the identification of the network function set comprises a domain name of the network function set.

14. The method according to any one of claims 1 to 2, wherein the information about the identification of the network capabilities set comprises a fully qualified domain name of the network capabilities set.

15. The method according to any one of claims 1 to 2, wherein the network function instance is no longer available due to at least one of the following: failure, restart, and in-scaling.

16. The method of any one of claims 1 to 2, wherein the indication that the network function instance is unavailable is received in a Gateway Restart Notification message.

17. The method according to any one of claims 1 to 2, further comprising: A home subscriber server is informed that the at least one packet data network connection has been transferred from the network function instance to the another network function instance, enabling the home subscriber server to update stored information about the at least one packet data network connection.

18. The method according to any one of claims 1 to 2, wherein the transferring may comprise: A transfer of the at least one packet data network connection from the network function instance to another network function instance included in the set of network functions is initiated.

19. An apparatus for communication, comprising means for performing the method according to any one of claims 1 to 18, wherein the apparatus is comprised in or comprises a mobility management entity.

20. A computer program product comprising computer executable instructions which, when executed by one or more processors of an apparatus, cause the apparatus to perform the method according to any one of claims 1 to 18.

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