WO2021016631A2 - Procédés et appareil de gestion de mobilité - Google Patents

Procédés et appareil de gestion de mobilité Download PDF

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Publication number
WO2021016631A2
WO2021016631A2 PCT/US2020/059700 US2020059700W WO2021016631A2 WO 2021016631 A2 WO2021016631 A2 WO 2021016631A2 US 2020059700 W US2020059700 W US 2020059700W WO 2021016631 A2 WO2021016631 A2 WO 2021016631A2
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WIPO (PCT)
Prior art keywords
application
information
upf
address
dns
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PCT/US2020/059700
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English (en)
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WO2021016631A3 (fr
Inventor
Kaippallimalil Mathew John
Mazin Ali AL-SHALASH
Khosrow Tony Saboorian
Zhixian Xiang
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Futurewei Technologies, Inc.
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Application filed by Futurewei Technologies, Inc. filed Critical Futurewei Technologies, Inc.
Publication of WO2021016631A2 publication Critical patent/WO2021016631A2/fr
Publication of WO2021016631A3 publication Critical patent/WO2021016631A3/fr

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements
    • H04W36/0005—Control or signalling for completing the hand-off
    • H04W36/0011—Control or signalling for completing the hand-off for data sessions of end-to-end connection
    • H04W36/0033—Control or signalling for completing the hand-off for data sessions of end-to-end connection with transfer of context information
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements
    • H04W36/12—Reselecting a serving backbone network switching or routing node
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L45/00—Routing or path finding of packets in data switching networks
    • H04L45/34—Source routing
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W40/00—Communication routing or communication path finding
    • H04W40/34—Modification of an existing route

Definitions

  • the present disclosure relates generally to methods and apparatus for digital communications, and, in particular embodiments, to methods and apparatus for mobility management.
  • Mobility management generally refers to functions of a communication network intended to support the movement of subscribers (e.g., user equipments (UEs)), allowing the continuous delivery of services, such as calls, content, data, messages, and so on, to the subscribers as the subscribers move about the communication system.
  • subscribers e.g., user equipments (UEs)
  • services such as calls, content, data, messages, and so on
  • the tasks involved with mobility management also become harder to implement.
  • a method implemented by a control plane function comprising: receiving, by the CPF from a first user plane function (UPF) associated with a user equipment (UE), segment route (SR) information and flow information, the UE being served by a first access node; participating, by the CPF, in a handover procedure, the handover procedure comprising the UE changing from being served by the first access node to being served by a second access node; selecting, by the CPF, a second UPF in accordance with the second access node serving the UE; and providing, by the CPF to the second access node and the second UPF, the SR information and the flow information.
  • UPF user plane function
  • SR segment route
  • the flow information comprising an address of an application server servicing the UE, a port number, and a routing protocol.
  • providing the SR information and the flow information comprising providing the SR information and the flow information to the second access node and the second UPF.
  • the SR information comprising segment t information.
  • the CPF comprising a session management function (SMF).
  • SMF session management function
  • a method implemented by an application server comprising: receiving, by the AS from a UE, a first application request addressed to an anycast address of an application; and sending, by the AS, a redirect request with a universal resource locator (URL) of a local data center, where the URL of the local data center resolves to the AS and the AS is a lowest cost route from the local data center to any one of a plurality of ASs hosting the application.
  • AS application server
  • first implementation form of the method according to the second aspect further comprising: advertising, by an application domain of the AS, a first route from the local data center to the AS having a first cost; and advertising, by the application domain of the AS, a second route from the local data center to an alternate AS having a second cost, where the first cost is less than the second cost.
  • the application domain comprising a local server.
  • the URL of the local data center resolves to a failure group anycast address.
  • the redirect request further comprising a pushed domain name server (DNS) translation of the URL to a failure group anycast address.
  • DNS domain name server
  • the URL of the local data center comprising a failure group anycast address.
  • a CPF comprising: one or more processors; and a non-transitory memory storage comprising instructions that, when executed by the one or more processors, cause the CPF to: receive, from a first UPF associated with a UE, SR information and flow information, the UE being served by a first access node; participate in a handover procedure, the handover procedure comprising the UE changing from being served by the first access node to being served by a second access node; select a second UPF in accordance with the second access node serving the UE; and provide, to the second access node and the second UPF, the SR information and the flow information.
  • the flow information comprising an address of an application server servicing the UE, a port number, and a routing protocol.
  • the instructions further causing the CPF to provide the SR information and the flow information to the second access node and the second UPF.
  • the SR information comprising segment t information.
  • the CPF comprising a session management function.
  • an AS comprising: one or more processors; and a non-transitory memory storage comprising instructions that, when executed by the one or more processors, cause the AS to: receive, from a UE, a first application request addressed to an anycast address of an application; and send a redirect request with a URL of a local data center, where the URL of the local data center resolves to the AS and the AS is a lowest cost route from the local data center to any one of a plurality of ASs hosting the application.
  • the instructions further causing the AS to: advertise a first route from the local data center to the AS having a first cost; and advertise a second route from the local data center to an alternate AS having a second cost, where the first cost is less than the second cost.
  • the URL of the local data center resolves to a failure group anycast address.
  • the redirect request further comprising a pushed DNS translation of the URL to a failure group anycast address.
  • the URL of the local data center comprising a failure group anycast address.
  • the instructions further causing the AS to: receive, from the UE, a second application request having a different source address than the first application request.
  • An advantage of a preferred embodiment is that application servers are selected to minimize distance between UEs and the application servers as the UEs move (and change access nodes or networks). Minimizing the distance between UEs and the application servers may reduce latency and improve overall performance.
  • Yet another advantage of a preferred embodiment is that it is possible to maintain connectivity with application servers, even when the UE has changed access nodes or networks. Not changing application servers when the UE moves can be advantageous in terms of server load, network condition, transition costs, etc.
  • Figure t illustrates an example communications system
  • Figure 2 illustrates an example communication system highlighting application servers
  • FIG. 3 illustrates a communication system highlighting methods and apparatus for selecting edge application servers (EASs) based on the location of user equipments (UEs) in the communication system according to example embodiments presented herein;
  • EASs edge application servers
  • Figure 4 illustrates a flow diagram of example operations occurring in the selecting EASs based on the location of UEs according to example embodiments presented herein;
  • FIG. 5A illustrates a flow diagram of example operations occurring in an application function (AF) provisioning information for a DNS authoritative according to example embodiments presented herein;
  • AF application function
  • Figure 5B illustrates a flow diagram of example operations occurring in a domain name server (DNS) authoritative selecting EASs based on the location of UEs according to example embodiments presented herein;
  • DNS domain name server
  • Figure 5C illustrates a flow diagram of example operations occurring in a DNS resolver selecting EASs based on the location of UEs according to example embodiments presented herein;
  • Figure 5D illustrates a flow diagram of example operations occurring in a UE resolving an IP address based on the location of the UE according to example embodiments presented herein;
  • Figure 6 illustrates a communication system highlighting anycast based server selection and re-selection following UE mobility according to example embodiments presented herein;
  • Figure 7 illustrates a communication system highlighting segment routing for a stateful application according to example embodiments presented herein;
  • Figure 8A illustrates a flow diagram of example operations occurring in an AF utilizing segment routing for server selection and re-selection with stateful applications according to example embodiments presented herein;
  • Figure 8B illustrates a flow diagram of example operations occurring in a UE utilizing segment routing for server selection and re-selection with stateful applications according to example embodiments presented herein;
  • FIG. 8C illustrates a flow diagram of example operations occurring in a session management function (SMF) utilizing segment routing for server selection and re selection with stateful applications according to example embodiments presented herein;
  • SMF session management function
  • Figure 9 illustrates a communication system highlighting operations for a UE
  • FIG. 1 Figure to illustrates an example communication system highlighting the informing of an application server (AS) of the change in IP attachment point according to example embodiments presented herein;
  • AS application server
  • Figure 11A illustrates a flow diagram of example operations occurring in a DNS being configured for anycast server selection according to example embodiments presented herein;
  • Figure 11B illustrates a flow diagram of example operations occurring in a UE participating in anycast server selection according to example embodiments presented herein;
  • Figure 11C illustrates a flow diagram of example operations occurring in an AS participating in anycast server selection according to example embodiments presented herein;
  • Figure 12 illustrates a diagram of operations occurring in and transmissions made by devices participating in EAS selection for stateful applications according to example embodiments presented herein;
  • Figure 13 illustrates a flow diagram of example operations occurring in an AF
  • Figure 14 illustrates an example communication system according to example embodiments presented herein;
  • Figures 15A and 15B illustrate example devices that may implement the methods and teachings according to this disclosure;
  • Figure 16 is a block diagram of a computing system that may be used for implementing the devices and methods disclosed herein.
  • FIG. 1 illustrates an example communications system too.
  • Communications system too includes an access node 110, with coverage area 101, serving user equipments (UEs), such as UEs 120.
  • Access node 110 is connected to a backhaul network 115 that provides connectivity to services and the Internet.
  • UEs user equipments
  • Backhaul network 115 that provides connectivity to services and the Internet.
  • a first operating mode communications to and from a UE passes through access node 110.
  • a second operating mode In a second operating mode,
  • access node 110 typically allocates resources used by the UE to communicate when specific conditions are met. Communication between a UE pair in the second operating mode occurs over sidelinks 125, comprising uni-directional communication links.
  • Communication between a UE and access node pair also occur over uni-directional communication links, where the communication links between the UE and the access node are referred to as uplinks 130, and the communication links between the access node and UE is referred to as downlinks 135.
  • Access nodes may also be commonly referred to as Node Bs, evolved Node Bs (eNBs), next generation (NG) Node Bs (gNBs), master eNBs (MeNBs), secondary eNBs (SeNBs), master gNBs (MgNBs), secondary gNBs (SgNBs), network controllers, control nodes, base stations, access points, transmission points (TPs), transmission -reception points (TRPs), cells, carriers, macro cells, femtocells, pico cells, and so on, while UEs may also be commonly referred to as mobile stations, mobiles, terminals, users, subscribers, stations, and the like.
  • Access nodes may provide wireless access in accordance with one or more wireless communication protocols, e.g., the Third Generation Partnership Project (3GPP) long term evolution (LTE), LTE advanced (LTE-A), 5G, 5G LTE, 5G NR, sixth generation (6G), High Speed Packet Access (HSPA), the IEEE 802.11 family of standards, such as 802.na/b/g/n/ac/ad/ax/ay/be, etc. While it is understood that communications systems may employ multiple access nodes capable of communicating with a number of UEs, only one access node and two UEs are illustrated for simplicity.
  • 3GPP Third Generation Partnership Project
  • LTE long term evolution
  • LTE-A LTE advanced
  • 5G LTE 5G LTE
  • 5G NR sixth generation
  • 6G sixth generation
  • 802.11 family of standards such as 802.na/b/g/n/ac/ad/ax/ay/be, etc. While it is understood that communications
  • DNSs Domain name servers
  • IP Internet Protocol anycast operation, along with route control, have been used by content delivery networks (CDNs) to select an application server (AS) that is located in the cloud.
  • the AS provides hardware and software resources to run applications requested by the UE.
  • the AS selected are typically located close to the UE making the request.
  • FIG. 2 illustrates an example communication system 200 highlighting application servers.
  • Communication system 200 includes an Internet Protocol (IP) network 205 that provides interconnectivity for devices making up communication system 200.
  • IP Internet Protocol
  • Communication system 200 includes access nodes (AN), such as AN 207, serving UEs, including UE 209.
  • AN access nodes
  • EASs edge application servers
  • Communication system 200 also includes edge application servers (EASs), such as EAS 211 and 212.
  • EASs edge application servers
  • a connection 213 exists between UE 209 and EAS 211.
  • the application domain uses client subnet information stored in DNS 215 to derive location information (of UEs, for example).
  • client subnet information and IP anycast is used to select one out of many appropriate EASs.
  • EAS 211 is shown in Figure 2 as being closer to UE 209 than EAS 212, hence EAS 211 is selected to serve UE 209.
  • LDNs Local Data Networks
  • MNO Mobile Network Operator
  • AF application function
  • BGP border gateway protocol
  • IXPs inter-exchange points
  • methods and apparatus are provided for providing information related to the location of UEs to a DNS.
  • the information may then be used to select an EAS closest to a UE, thereby helping to meet stringent latency requirements associated with EC.
  • the proximate location of a LDN, relative to the access location of a UE is identified.
  • the information e.g., IP address of a user plane function (UPF), location of a LDN, and so forth, may be used to provision an AF (i.e., the application controller).
  • the AF utilizes the information, along with other policy criteria, to populate data at a DNS.
  • the DNS receives a name resolution request from a UE
  • the IP address of an EAS closest to the UE (as derived from the data stored at the DNS and the IP address of the UE) is provided.
  • the communication latency between the UE and the EAS is potentially minimized.
  • Figure 3 illustrates a communication system 300 highlighting methods and apparatus for selecting EASs based on the location of UEs in the communication system.
  • Communication system 300 includes a 5G system (5GS) 305 providing connectivity for UEs (such as UEs 307 and 308) to an IP network 310.
  • the UEs are connected to IP network 310 by way of gNBs, such as gNB 311, and UPFs, such as UPFs 312 and 313.
  • the UPFs serve an IP address range, such as range X for UPF 312 and range Y for UPF 313, for example.
  • Communication system 300 also includes a mobile network operator (MNO) 315 that hosts EC servers, such as AS 316 in LDN 318 and AS 317 in LDN 319, which are connected to IP network 310.
  • Communication system 300 also includes cloud computing resources, such as AS 320, which are connected to IP network 310 by way of external IP networks 322 and IXP 324.
  • MNO mobile network operator
  • the UE access is proximate to LDNs, such as LDN 318 or LDN 319, based on
  • IP path between UPF 313 and LDN 319
  • congestion of the path across IP network 310 e.g., an IP path between UPF 313 and LDN 319
  • information regarding which LDN and EAS is optimal when a UE tries to access from a UPF is provisioned and used to select the optimal EAS.
  • this information is provisioned to the DNS, which is used to steer incoming IP data packets to the optimal EAS.
  • MNO 315 provisions UPFs and LDNs that host EC servers by storing information in a network resource function (NRF) 325.
  • a network data analytics function (NWDAF) 327 and other network functions (NFs) of 5G core (5GC) 329 generates the information and sends the information to AF 331.
  • NWDAF network data analytics function
  • NFs network functions
  • the information may provide, to AF 331, knowledge regarding location, congestion, etc., for access to EAS, such as EAS 316 and 317.
  • the information may be generated in accordance with dynamic measurement information of IP traffic, bandwidth availability, congestion in IP network paths between UPFs and LDNs (e.g., paths of IP network 310), and so on.
  • An example of the provisioning of the information and the selection of an EAS based on the location of a UE is presented below.
  • a network edge function (NEF) 333 of 5GC 329 provides record information to AF 331 (event #1 335). Examples of the record information may be as follows:
  • IP address range [ X ]
  • LDN LDN-t
  • preference high
  • IP path traffic characteristics
  • IP address range [ Y ]
  • LDN LDN-2
  • preference medium
  • IP path traffic characteristics
  • IP address ranges correspond to source or UE location and points to a set of UPFs that terminate the protocol data unit (PDU) session.
  • PDU protocol data unit
  • AF 331 uses the record information provided by NEF 333, along with any policy information in the application domain (including but not limited to cost of access, access priority, and so on), and provisions DNS authoritative 337, which is also referred to as the DNS backend (event #2 339).
  • the provisioning of DNS authoritative 337 may proceed as follows: if a DNS query is from IP address range [X], then return an LDN or EAS address for the LDN in the DNS response. A DNS query with a UE IP address within in IP address range [X] will return a LDN or EAS address.
  • AF 331 may provision an IP address corresponding to an EAS, or AF 331 may provision an IP anycast address corresponding to a set of LDNs or EASs.
  • a group of LDNs is indicated with one IP anycast address provisioned in AF 331 or DNS authoritative 337.
  • the provisioned IP anycast address points to a set of LDNs in a geographical location.
  • Each LDN in the set of LDNs may advertise route priority dynamically to IP network 310. If multiple LDNs advertise the same priority, IP network 310 uses round robin resolution to select an LDN, for example.
  • the grouping of LDNs and EASs may be by configuration performed at AF 331. Thus, the grouping is flexible.
  • DNS authoritative 337 has been configured to direct the name resolution based on the location of the requesting UE, as well as the location of the UPF.
  • the provisioning of DNS authoritative 337 enables DNS authoritative 337 to serve requests from UEs and select optimal LDNs or EASs.
  • UE 308 has setup a PDU session between UE 308 and UPF 313. Any IP datagrams to the external network (e.g., LDNs or EASs) are forwarded by UPF
  • the application domain comprises MNO hosted EASs, and UE 308 sends a DNS query to DNS resolver 341 (event #3 343).
  • DNS resolver 341 If DNS resolver 341 does not have a cached entry for the IP address included in the DNS query, DNS resolver 341 sends the DNS query to DNS authoritative 337 (event #4 345).
  • DNS resolver 341 may add client subnet information (as presented in RFC 7871, which is hereby incorporated herein by reference in its entirety) to assist DNS authoritative 337 with determining the location of UE 308.
  • DNS queries over Hypertext Transfer Protocol Secure (HTTPS) DoH
  • DoH Hypertext Transfer Protocol Secure
  • DNS authoritative 337 inspects the URL of the DNS request, as well as the IP information of UE 308, to determine a response record.
  • DNS authoritative 337 uses information provisioned in events #1337 and #2 339 to populate the A record or the AAAA record with the IP address of the EAS (e.g., EAS 317).
  • DNS authoritative 337 sends the A record (or the AAAA record) to DNS resolver 341 (event #5 347). If there are multiple LDNs and EASs, the provisioning performed in events #1 337 and #2 339 would provide an IP anycast address that is pointing to the set of LDNs or EASs.
  • the IP anycast address may point to area-B 349. IP anycast resolution may be based on dynamic route control where the LDNs advertise routes to the EASs.
  • DNS resolver 341 caches the A record (or the AAAA record) and forwards the DNS response to UE 308 (event #6 351). DNS resolver 341 may cache the IP address included in the A record (or the AAAA record), for example.
  • IP datagram e.g., HTTPS, Message Queuing Telemetry Transport (MQTT), etc.
  • MQTT Message Queuing Telemetry Transport
  • the IP datagram is forwarded to UPF 313 as part of the PDU session, and UPF 313 forwards the packet with the IP address of EAS 317. If the IP address is a standard address, normal IP forwarding is used to reach EAS 317. However, if the IP address is an anycast address, the dynamic information in IP network 310 is used to select the best EAS (e.g., EAS 317).
  • IP datagram e.g., HTTPS, Message Queuing Telemetry Transport (MQTT), etc.
  • MQTT Message Queuing Telemetry Transport
  • the specific information provisioned by 5GC 329 into AF 331 and DNS resolver 341 and DNS authoritative 337 is used to provide the best IP address for the EAS server for a specific UE or UPF access location.
  • Figure 4 illustrates a flow diagram of example operations 400 occurring in the selecting EASs based on the location of UEs.
  • Operations 400 may be indicative of operations occurring in the selection of EASs based on the location of UEs.
  • Operations 400 begin with the provisioning of a DNS with information from a 5GC (block 405).
  • the information may include one or more records, with each record including an IP address range, LDN address, traffic characteristics, and so forth. Both a DNS resolver and a DNS authoritative may be provisioned with the information.
  • the provisioning of the DNS may involve interaction with an AF.
  • the selection of the EASs also includes the selection of an optimal LDN or EAS for a UE (block 407).
  • the selection of the optimal LDN or EAS may be in accordance with the location of the UE.
  • the information provisioned at the DNS is used to select a LDN or EAS or a set of LDNs or EASs that are optimal for the UE based on the location of the UE or the location of the UPF of the UE. If a LDN or EAS is selected, then an actual IP address of the selected LDN or EAS is provided to the UE. If a set of LDNs or EASs is selected, then an anycast address is provided to the UE. IP anycast address resolution may be based on dynamic route control and advertised routes to EASs.
  • Figure 5A illustrates a flow diagram of example operations 500 occurring in an AF provisioning information for a DNS authoritative.
  • Operations 500 may be indicative of operations occurring in an AF as the AF provisions information for a DNS authoritative usable in selecting EASs based on the location of UEs.
  • Operations 500 begin with the AF receiving record information from the 5GC (block 505).
  • the information may include one or more records, with each record including an IP address range, LDN address, traffic characteristics, and so forth.
  • the information may provide knowledge regarding location, congestion, etc., for access to EASs.
  • the information may be generated in accordance with dynamic measurement information of IP traffic, bandwidth availability, congestion in IP network paths between UPFs and LDNs, and so on.
  • the AF combines the record information provided by the 5GC, along with any policy information in the application domain (including but not limited to cost of access, access priority, and so on) (block 507) and provisions the DNS authoritative (block 509).
  • the provisioning of the DNS authoritative may proceed as follows: if a DNS query is from IP address range [X], then return an LDN or EAS address for the LDN in the DNS response.
  • a DNS query with a UE IP address within in IP address range [X] will return a LDN or EAS address.
  • the AF may provision an IP address corresponding to an EAS, or the AF may provision an IP anycast address corresponding to a set of LDNs or EASs.
  • Figure 5B illustrates a flow diagram of example operations 515 occurring in a DNS authoritative selecting EASs based on the location of UEs.
  • Operations 515 maybe indicative of operations occurring in a DNS authoritative as the DNS authoritative is provisioned with information and selects EASs based on the location of UEs.
  • Operations 515 begin with the DNS authoritative being provisioned with information (block 520).
  • the information being provisioned to the DNS authoritative may include record information provided by a 5GC, along with policy information in the application domain.
  • the information is provisioned so that a DNS query includes an IP address in IP address range [X], the DNS authoritative returns an LDN or EAS address for the LDN in the DNS response.
  • the DNS authoritative receives a DNS query, i.e., an address resolution request (block 522).
  • the DNS query may be received from a DNS resolver when the DNS resolver does not have cached information to resolve the DNS query.
  • the DNS query from the DNS resolver may include client subnet information that may assist the DNS authoritative in determining the location of a UE making the DNS query.
  • the DNS authoritative determines the response record (block 524).
  • the response record may be an A record or an AAAA record.
  • the A record or AAAA record may include an IP address of a LDN or EAS or an IP anycast address of a set of LDNs or EASs.
  • the DNS authoritative sends a DNS response, i.e., an address resolution response (block 526).
  • the DNS response may be sent to the DNS resolver.
  • FIG. 5C illustrates a flow diagram of example operations 530 occurring in a DNS resolver selecting EASs based on the location of UEs.
  • Operations 530 may be indicative of operations occurring in a DNS resolver as the DNS resolver is selects EASs based on the location of UEs.
  • Operations 530 begin with the EAS resolver receiving a DNS query, i.e., an address resolution request (block 535).
  • the DNS query may be received from a UE that has launched an application and has a need to resolve the IP address of an EAS for the application in the application domain. If the EAS resolver has cached information resolving the IP address, the DNS resolver sends a DNS response with the cached information (block 541).
  • the DNS resolver sends an address resolution request to a DNS authoritative (block 537) and receives an address resolution response with the resolved address from the DNS authoritative (block 539).
  • the DNS resolver caches the resolved address (along with the IP address that resolved to the resolved address) and sends the DNS response with the resolved address (block 541).
  • Figure 5D illustrates a flow diagram of example operations 545 occurring in a UE resolving an IP address based on the location of the UE.
  • Operations 545 may be indicative of operations occurring in a UE as the UE resolves an IP address in accordance with the location of the UE.
  • Operations 545 begin with the UE sending a DNS query (block 550).
  • the DNS query is sent to a DNS resolver.
  • the DNS query may include an IP address for a URL of an application launched by the UE.
  • the UE receives a DNS response (block 552).
  • the DNS response includes an IP address of a LDN or EAS or an IP anycast address of a set of LDNs or EASs that have been selected in accordance with the location of the UE or a UPF serving the UE.
  • the LDN or EAS or set of LDNs or EASs may have been selected to minimize latency, cost, error rate, congestion, etc., of a path between the UE and the LDN or EAS.
  • the UE sends an IP datagram application request (block 554).
  • the IP datagram application request may include the IP address of the EAS provided in the DNS response.
  • the IP datagram application request is forwarded in accordance with the IP address included in the IP datagram application request. In the situation when the IP address is an IP anycast address, dynamic information is used to select the best EAS for the UE.
  • FIG. 6 illustrates a communication system 6oo highlighting anycast based server selection and re-selection following UE mobility.
  • Communication system 6oo includes a UE 605 connected to a first EAS 607 by way of a path 609, which is a route from A to El.
  • Path 609 encompasses a first gNB 611, a first user plane function (UPF) 613, and an IP network 615 comprising routers 617 and 618.
  • UPF user plane function
  • UE 605 is mobile and moves about communication system 600.
  • UE 621 represents UE 605 at a particular time instance. Due to the mobility, UE 621 is no longer served by first gNB 611.
  • a 5G Core (5GC) 623 has managed the mobility of UE 621, selecting a new gNB (i.e., second gNB 625) and a new UPF (i.e., second UPF 627) to serve UE 621. Based on the new location of UE 621 and second UPF 627, UE 621 is connected to a second EAS 629 by way of a path 631, which is a route from A to E2.
  • Path 631 encompasses second gNB 625, second UPF 627, and routers 633, 634, 635, and 636.
  • second EAS 629 may be selected for UE 621 because the routers of IP network 615 have no flow state associated with UE 605 or 621.
  • the selection of the EAS by the routers of IP network 615 may lead to undesired consequences because the selection of the EAS typically does not consider factors such as server load, network status, cost of transmissions, DDoS policies, UE mobility indications, and so on.
  • the selection of the EAS should occur in the application domain, where the above factors may be taken into consideration when selecting EASs. Therefore, there is a need for methods and apparatus for server selection and re-selection due to mobility. The methods and apparatus should not add additional state to the IP network.
  • the IP forwarding plane of IP networks avoids maintaining per-session state information for high scalability reasons.
  • the problem discussed above is due to the routers in the N6/IP network translating an IP anycast address into an actual IP address not having per-session or per-UE state information in the IP forwarding plane.
  • AS application server
  • Existing techniques for handling sticky server selection for stateful operation is to steer traffic at the application layer using Layer 7 (L7) load balancers.
  • Application layer session persistence can track source IP address, secure socket layer (SSL) session identifiers, and hypertext transfer protocol (HTTP) cookies. However, this does not help with optimal forwarding to an appropriate data center or application location following UE mobility.
  • methods and apparatus for server selection and re-selection due to mobility are provided.
  • the methods and apparatus presented herein consider factors such as server load, network status, cost of transmissions, DDoS policies, UE mobility indications, and so on, when moving a server due to mobility.
  • the methods and apparatus presented utilize application domain decision making to perform server selection and re-selection.
  • the methods and apparatus presented support UE mobility, server mobility, and multicast.
  • Segment routing is a source based routing technique that removes network state information from routers and nodes and places path state information in the packet headers. Because the state information is located in the packets, segment routing is responsive to network changes. When a packet arrives at a segment node, the segment node examines the outermost header and forwards the packet to the next segment node. This continues until the packet reaches the final segment endpoint.
  • Segment routing is a useful mechanism to steer traffic.
  • the ability to steer traffic is enhanced with public data network (PDN) session handling state information usable in selecting the AS (or EAS in edge computing applications) and to continue to route to the same AS when a stateful application is used.
  • PDN public data network
  • Table t outlines an example DNS configuration
  • Table 2 outlines an example segment routing and IP routes.
  • DNS segment routes, and IP routes may be configured ahead of processing a UE application request to an edge computing (EC) domain.
  • the DNS configuration such as shown in Table 1, consists of A records and AAAA records distributed for a wide area (e.g., an entire continent).
  • the segment routes and IP routes such as shown in Table 2, are programmed in a UPF PDU session anchor (PSA) and N6 IP network.
  • PSA PDU session anchor
  • N6 IP network There may be a translation from a DNS provided anycast address (e.g., G-4) to a list of segment routes (e.g., SEGt).
  • the segment routes may comprise a list of segments (e.g., SEGt comprises SEG-a, SEG-d, and SEG-li) that route from the UPF-PSAto a LDN (e.g., an EC site).
  • the segment routing may utilize multiprotocol label switching (MPLS) or segment routing over IPv6 dataplane (SRv6) technology. If MPLS is utilized, the UPF-PSA should be capable of supporting MPLS, and similarly for SRv6.
  • the DNS and router or UPF configuration are used to steer and manage application level requests from the UE.
  • FIG. 7 illustrates a communication system 700 highlighting segment routing for a stateful application.
  • Communication system 700 includes a UE 705 that, due to UE mobility (event #8 707), is represented as UE 709.
  • an AF 711 configures a DNS 713 with translations (e.g., A records or AAAA records for translation of app.net to IP addresses) (event #1 715).
  • AF 711 also configures a software defined network core (SDN- C) 717 with segment routing and IP routes to select and steer application traffic from a UPF-PSA to an EC application domain (events #2 721).
  • SDN- C software defined network core
  • Figure 7 illustrates a centralized approach, involving SDN-C 717, but the example embodiments also support border gateway protocol (BGP) based route injection or other distributed routing protocols that program N6 IP network 723 and the UPF-PSA.
  • BGP border gateway protocol
  • communication system 700 may be ready to handle application requests from UE 705.
  • UE 705 For discussion purposes, it is assumed that UE 705 has established a PDU session over which the application connection request is sent. UE 705 launches an application and sends a DNS query to DNS 713 to resolve the application name (app.net) (event #3 725). DNS 713 may respond with A records or AAAA records, for example. For the remainder of the discussion of Figure 7, IPv4 (G-4) nomenclature is used.
  • UE 705 initiates an application request (e.g., using HTTPS) with destination address G-4 (event #4 727).
  • the application request may be sent over path 729, which comprises a first gNB 731, a first UPF 733, and IP network 723 (which includes routers 735 and 736).
  • the application request PDU is forwarded to first UPF 733, and first UPF 733 terminates the general packet radio service (GPRS) tunneling protocol (GTP) connection and looks up a translation for destination address G-4.
  • GPRS general packet radio service
  • GTP general packet radio service
  • First UPF 733 obtains the segment routes and inserts segment routing information (e.g., SR-MPLS, SRv6, etc.) in the PDU.
  • segment routing information e.g., SR-MPLS, SRv6, etc.
  • first UPF 733 reports the segment routing along with a flow 3-tuple (comprising the IP destination address, ports, and protocol) to a session management function (SMF) 743 of a 5GC 745.
  • SMF session management function
  • first UPF 733 reports the SEGt list to SMF 743 (event #5 747).
  • flow 3- tuple and segment routing lists are used to route application requests to an AS.
  • the handover procedure includes the selection of a second UPF 751 by SMF 743.
  • Standard handover procedures such as those described in 3GPP TS 23.501 and 3GPP TS 23.502 may be followed.
  • the standard handover procedure also involves an access and mobility management function (AMF) 753.
  • AMF access and mobility management function
  • SMF 743 may program the segment routes (e.g., SEGt) and the flow 3-tuple selected for the PDU session at second gNB 755 and second UPF 751 (event #7757).
  • the standard handover procedure includes establishing a PDU session for UE 709 at its new location (event #8 707).
  • UE 709 continues to receive packets on first gNB 705 for a short period of time.
  • UE 709 initiates an application layer message at every gNB change (even in situations where there is nothing to send) (event #9 759).
  • the application layer message may be used to ensure that pending downstream packets are directed to UE 709 attached to second UPF 751.
  • the messages are routed using the segment routing information in second UPF 751, thus are steered to EAS 741.
  • Figure 8A illustrates a flow diagram of example operations 800 occurring in an AF utilizing segment routing for server selection and re-selection with stateful applications.
  • Operations 800 may be indicative of operations occurring in an AF as the AF uses segment routing for server selection and re-selection with stateful applications.
  • Operations 800 begin with the AF configuring a DNS (block 805).
  • the AF may configure the DNS with translations (e.g., A records or AAAA records for translation of app.net to IP addresses).
  • the AF configures SDN-C (block 807).
  • the AF also configures the SDN-C with segment routing and IP routes to select and steer application traffic from a UPF- PSA to an EC application domain.
  • Figure 8B illustrates a flow diagram of example operations 815 occurring in a UE utilizing segment routing for server selection and re-selection with stateful applications.
  • Operations 815 may be indicative of operations occurring in a UE as the UE uses segment routing for server selection and re-selection with stateful applications.
  • Operations 815 begin with the UE launching an application and sending a DNS query (block 820).
  • the DNS query may be sent to a DNS to resolve the application name, for example.
  • the UE receives a DNS response with the resolved application name.
  • the UE initiates an application request (block 822).
  • the application request includes the destination address of the application (as received in the DNS response, for example).
  • the UE participates in a handover procedure (block 824).
  • the handover procedure is initiated when the UE moves out of coverage of a first gNB and into coverage of a second gNB, for example.
  • the handover procedure results in the population of a flow 3-tuple and segment routing list at a new UPF associated with the second gNB.
  • the UE initiates an application layer message (block 826).
  • the application layer message may be sent to ensure that pending downstream packets are directed to the UE attached to the second UPF.
  • the messages are routed using the segment routing information in the second UPF, thus are steered to the AS of the UE.
  • Figure 8C illustrates a flow diagram of example operations 835 occurring in a SMF utilizing segment routing for server selection and re-selection with stateful applications.
  • Operations 835 may be indicative of operations occurring in a SMF as the SMF uses segment routing for server selection and re-selection with stateful applications.
  • Operations 835 begin with the SMF receiving segment routing and flow information (block 840).
  • the SMF receives the flow 3-tuple from a first UPF.
  • first UPF reports the SEGt list to the SMF.
  • flow 3-tuple and segment routing lists are used to route application requests to an AS of a UE.
  • the SMF participates in a handover procedure (block 842).
  • the handover procedure is initiated when the UE moves out of coverage of a first gNB and into coverage of a second gNB, for example.
  • the handover procedure results in the SMF populating the flow 3-tuple and segment routing list at a new UPF associated with the second gNB. This may be accomplished by the SMF selecting the second UPF (block 844) and providing the segment routing and flow information to the second UPF (block 846).
  • anycast is used extensively by various application providers and CDNs because anycast operation makes it possible to dynamically perform load balancing across servers without adding a network-level load balancer. This advantage enables anycast based solutions to be very robust.
  • the DNS may be configured with an IP anycast address in an A record or an AAAA record per fully qualified domain name (FQDN) for an entire region or continent.
  • a technique involving the configuring of DNS A or AAAA record translations with global and local scope may be used.
  • the application may start with global FQDN information that is translated to an anycast address.
  • a local URL and application layer redirect operation e.g., HTTPS 3xx
  • HTTPS 3xx may be used to send application traffic from the UE to the same AS, even after UE mobility.
  • Table 3 outlines an example DNS configuration
  • Table 4 outlines an example IP routes supporting anycast server selection.
  • Example DNS A and AAAA record translations with global and local scope are provided.
  • the IP route configuration (Table 4) has translations.
  • FIG. 9 illustrates a communication system 900 highlighting operations for a UE establishing an application connection or flow to an EAS using specific URLs.
  • Communication system 900 includes a UE 905 that, due to UE mobility (event #8 907), is represented as UE 909.
  • DNS local tables are configured to route requests to locally selected AS.
  • an AF 911 configures a DNS 913 with translations (e.g., A records or AAAA records for translation of app.net to IP addresses, and local scope, i.e., ldn(x).op(x).app.net) (event #1 915).
  • AF 911 also configures a SDN-C 917 with IP routes (e.g., Table 4: IP Routes 2:) to select and steer application traffic from a UPF- PSAto an EC application domain (events #2 921).
  • IP routes e.g., Table 4: IP Routes 2:
  • Table 4 describes IP routes for the global anycast address (G-4) and the local/failure group anycast addresses (Li, L2, L3).
  • G-4 global anycast address
  • L2 local/failure group anycast addresses
  • a second layer local anycast/failure group anycast route allows packets of the same flow to be routed to the same server location (i.e., an LDN) even after a handover, whereinafter the UE uses a new source IP address.
  • the routing cost of G-4 to LDNt, LDN2, or LDN3 (which are identified by gateway addresses El, E2, and E3 in this example respectively) maybe the same if each of the sites (LDNt, LDN2, and LDN3) have about the same distance from the ingress point.
  • a destination LDN is selected (e.g., G-4 - Et)
  • This is accomplished by the application server sending a redirect message to cause subsequent messages to be sent to the local/failure group anycast address.
  • this may be accomplished by having the advertised route for Li to Et having a low cost and advertised routes from Li to E2 and E3 having very high costs. This helps to ensure that the IP network always forwards to LDNt (i.e., Et) unless there is a failure of site LDNt.
  • the application server sends a redirect with a URL that the DNS translates to Li.
  • the application server may send a redirect with a URL and a pushed DNS translation (using DNS over HTTPS semantics, for example). This allows the UE to obtain the translation without an additional network DNS lookup.
  • the application server sends the local/failure group anycast address (e.g., Li) directly in the redirect message.
  • Figure 9 illustrates a centralized approach, involving SDN-C 717, but the example embodiments also support BGP based route injection or other distributed routing protocols that program N6 IP network 923 and the UPF-PSA.
  • communication system 900 may be ready to handle application requests from UE 90S-
  • UE 905 For discussion purposes, it is assumed that UE 905 has established a PDU session over which the application connection request is sent. UE 905 launches an application and sends a DNS query to DNS 913 to resolve the application name (app.net) (event #3 925). DNS 913 may respond with A records or AAAA records, for example. For the remainder of the discussion of Figure 9, IPv4 (G-4) nomenclature is used.
  • UE 905 initiates an application request (e.g., using HTTPS) with destination address G-4 over the PDU session (event #4 927).
  • the application request may be sent over a path, which comprises a first gNB 931, a first UPF 933, and N6 IP network 923.
  • the application request PDU is forwarded to first UPF 933, and first UPF 933 terminates the GTP connection and forwards the IP packet with destination address G-4 to N6 IP network 923.
  • Routers in N6 IP network 923 (as configured in event #2 921) select an EAS (for discussion purposes, consider the situation where EAS 941 is selected).
  • EAS 941 issues a redirect request with a new URL (event #5 943).
  • the new URL may be set to that of a local data center, e.g., ldni.opt.app.net.
  • the IP address translation directs packets to EAS 941, except in the case of a site failure.
  • UE 905 sends a DNS query to DNS 913 to resolve the new URL, e.g., ldni.opt.app.net, and DNS 913 replies with a DNS response with anycast address Li (event #6 945).
  • the EAS 941 may send the anycast address Li directly to UE 905 in which case no additional DNS translation is required.
  • the EAS 941 may send the new URL along with an embedded DNS translation for it using DoH (DNS over HTTPS) encoding in the redirect.
  • the embedded DoH message contains a translation from the URL (e.g., ldni.opt.app.net) to A record with anycast address (e.g, Li).
  • UE 905 continues application requests with anycast destination address Li (event #7 947).
  • the PDU is forwarded to first UPF 933 and first UPF 933 terminates the GTP and forwards an IP packet with anycast destination address Li to N6 IP network 923. Routing rules configured assure that anycast destination address Li is always forwarded to EAS 941, except in the case of an LDNt site failure.
  • UE 905 participates in a standard handover procedure where UE 909 establishes a PDU session from a new location (event #8 907). Part of the handover procedure involves SMF 943 populating information to a second UPF 951 selected for UE 909 based on second gNB 955. In the case of SSC mode 3, UE 909 continues to receive packets from first gNB 931 for a short period of time. UE 909 initiates an application layer message at every gNB change (even in situations where there is nothing to send) (event #9 959). The application layer message may be used to ensure that pending downstream packets are directed to UE 909 attached to second UPF 951.
  • procedure specified in 3GPP TS 23.502 may be used to keep the old PDU session active for a specified period of time. This period of time is conveyed to the UE in protocol configuration options (PCO).
  • PCO protocol configuration options
  • branching point UPF functionality as described in 3GPP TS 23.502, section 3.5.2 may be used to steer flows from the old UPF to the branching point UPF, which in turn, delivers the packets to the UE.
  • the branching point UPF may be deployed together with a new UPF.
  • 3GPP TS 23.502 section 3.5.2 specifies that mechanisms used by the UE to proactively move existing traffic flows from one IP address or prefix to another is outside the scope of 3GPP TS 23.502, section 4 ⁇ 3 ⁇ 5.2.
  • flows involved with EC one key requirement is to accomplish the transition with low latency and jitter.
  • active techniques at the application layer can help performance.
  • an upstream application level message is used to indicate to the AS or EAS that the IP attachment point has changed.
  • FIG. 1000 Figure to illustrates an example communication system 1000 highlighting the informing of an AS of the change in IP attachment point.
  • Communication system 1000 includes a UE 1005 with a PDU session established with an AS 1007.
  • UE 1005 has also setup the application details to receive a stream of downstream messages or notifications.
  • An application 1009 in UE 1005 also has registered interest to receive notifications on connection changes from an operating system of UE 1005 or a connection handler ton.
  • AS 1007 sends application messages to the destination IP address of UE 1005.
  • the application messages traverse through N6 IP network 1015, which forwards the application messages to second UPF 1017 using destination routing.
  • Second UPF 1017 uses PDU session forwarding to send the application messages to UE 1005 (through backhaul (BH) (N3, N9) 1019, and second gNB 1021).
  • BH backhaul
  • a mobile terminal 1023 in UE 1005 delivers the application messages to application 1009, as setup by the operating system of UE 1005 or connection handler ton (event #1* 1025).
  • UE 1005 moves out of coverage of second gNB 1021 or is instructed to participate in a handover procedure, operations are performed by a 5GC 1027 to initiate a handover, setup session context in a first gNB 1029 and a first UPF 1031, as well as remove session context from second gNB 1021 and second UPF 1017 (event #2 1033).
  • UE 1005 has a new IP address with first UPF 1031 being the IP attachment point.
  • 5GC 1027 may maintain a path from second UPF 1017 to first UPF 1031 for a period of time, for SSC mode 3 to make the handover process more seamless.
  • Connection handler ton (or the operating system of UE 1005) manages the new IP address or PDU connection and notifies application 1009 of the change of network address (event #3 1035).
  • Application 1009 binds to new socket or IP address and sends a message to AS 1007 (event #4 1037).
  • messages are triggered as a result of a new PDU connection.
  • AS 1009 inspects the source address and sends subsequent downstream messages to the new IP address of UE 1005, which are forwarded by first UPF 1031.
  • Application messages from UE 1005 to AS 1007 may be keepalive messages.
  • IP multicast e.g., Internet group management protocol (IGMP), multicast listener group (MLD), etc.
  • stage change record messages to subscribe to the multicast stream are sent.
  • First UPF 1031 may be a rendezvous point that forwards the stream to UE 1005.
  • the old multicast stream may timeout.
  • Flows or messages are sent with the new destination IP address of UE 1005.
  • multicast handling is performed by first UPF 1031.
  • Figure 11A illustrates a flow diagram of example operations 1100 occurring in a DNS being configured for anycast server selection.
  • Operations 1100 may be indicative of operations occurring in a DNS as the DNS is configured for anycast server selection.
  • the DNS may be configured by an AF of the communication system.
  • the DNS may be configured with A records or AAAA records for translation of a global scope and a local scope.
  • An example of global scope translation is app.net to IP address translation, while a local scope translation is ldn(x).op(x).app.net, for example.
  • the DNS resolves an application name (block 1107).
  • the DNS receives a DNS query with an application name and the DNS utilizes the configured translations to resolve the application name.
  • the DNS responds with a DNS response with A records or AAAA records, for example.
  • the DNS resolves a redirect URL (block 1109).
  • the DNS receives a DNS query with a redirect URL (which may be a URL of a local data center, for example).
  • the DNS resolves the redirect URL using the configured translations, for example, and responds with an anycast address.
  • Figure 11B illustrates a flow diagram of example operations 1150 occurring in a UE participating in anycast server selection.
  • Operations 1150 may be indicative of operations occurring in a UE as the UE participates in anycast server selection.
  • Operations 1150 begin with the UE launching an application and sending a DNS query (block 1155).
  • the UE sends the DNS query to resolve the application name and receives a destination address.
  • the UE initiates an application request (block 1157).
  • the application request includes the destination address of the application, as resolved by the DNS.
  • the UE receives a redirect request (block 1159).
  • the redirect request includes a new URL and is received from the AS of the application because the application is stateful.
  • the new URL may be set to the local data center.
  • the UE resolves the redirect URL (block 1161).
  • the UE may resolve the redirect URL by sending a DNS query to the DNS, with the DNS query including the redirect URL.
  • the UE receives an anycast address for the redirect URL.
  • the UE requests the destination address (block 1163).
  • the UE may send a PDU that is forwarded to the UPF of the UE, and the UPF forwards an IP packet with the destination address to the N6 IP network, where routing rules configured assure that the anycast address is forwarded to the AS.
  • the UE participates in a handover process (block 1165).
  • the handover process may be initiated by the UE moving out of the coverage of a first gNB and into the coverage of a second gNB.
  • the UE initiates an application layer message (block 1167).
  • the application layer message ensures that pending downstream packets are directed to the UE as it is attached to the second UPF.
  • Figure 11C illustrates a flow diagram of example operations 1175 occurring in an AS participating in anycast server selection.
  • Operations 1175 may be indicative of operations occurring in an AS as the AS participates in AS server selection.
  • Operations 1175 begin with the AS receiving the application request from a UE (block 1180).
  • the application request from the UE include the destination address of an application, as resolved by a DNS.
  • the AS was selected out of a plurality of potential AS, as an example, the AS is selected by routers in the N6 IP network.
  • the AS issues a redirect request (block 1182).
  • the redirect request includes a new UR.
  • the URL is set to the address of a LDN, e.g., ldni.opt.app.net.
  • the translation of the URL directs packets to the AS, except in the case of a site failure.
  • the LDNs have advertised IP routes with costs configured so that routers in N6 IP network will select the AS (except in the case of a site failure).
  • the LDNs advertise routes with the advertised route for Li to El having a low cost and advertised routes from Li to E2 and E3 having very high costs. Hence, the route for Li to Et would be chosen due to lower cost.
  • the route advertising may occur prior to the redirect request by the AS, for example.
  • the AS may send a redirect request with a URL and a pushed DNS translation (using DNS over HTTPS semantics, for example). This allows the UE to obtain the translation without an additional network DNS lookup.
  • the AS sends the local/failure group anycast address (e.g., Li) directly in the redirect request.
  • the AS receives an application request from the UE (block 1184). Because the UE has not moved, the source and destination addresses of the request remain as before.
  • the AS receives an application request from the UE post handover (block 1186). In this situation, the UE has participated in a handover and has a different source address. However, due to the redirect request from the AS in block 1182, the packets from the UE continue to be delivered to the AS.
  • Figure 12 illustrates a diagram 1200 of operations occurring in and transmissions made by devices participating in EAS selection for stateful applications.
  • the devices include a UE 1205, an access network (AN) 1207, a first UPF 1209, a second UPF 1211, a N6 IP network 1213, an EAS/LDN 1215, and a DNS 1217.
  • AN access network
  • server discovery is performed.
  • UE 1205 attaches and establishes a PDU session with first UPF t209 ⁇ UE t205 also launches an application and translates the FQDN (block t222).
  • a DNS query results in a destination address for the application (event t224).
  • UE t205 sends an application message with the destination address and routers in N6 IP network t2t3 select EAS/LDN t2t5 (the closest or otherwise best EAS/LDN for the application) and forwards the packet (event t226).
  • EHE edge hosting environment
  • first UPF 1209 selects the segment route list to forward to EAS/LDN 1215.
  • First UPF 1209 sends the flow 3- tuple and segment route list to the SMF as the flow state.
  • EAS/LDN 1215 issues a redirect with URL.
  • the redirect URL translation selects EAS/LDN 1215 for subsequent packets, except in the case of failure or other explicity redirect from the application domain.
  • UE 1205 sends a DNS query for the domain name and obtains the answer with A record or AAAA record with an anycast address.
  • the anycast address is translated by N6 IP network 1213 to EAS/LDN 1215 unless there is a site failure. In such a situation, other LDNs of the set of LDNs including EAS/LDN 1215 may be options.
  • UE 1205 sends application messages with the anycast destination address.
  • Routers in N6 IP network 1213 select EAS/LDN 1215 (which is preferred for the anycast destination address) and forwards the packets. Routers forward the packets to EAS/LDN 1215.
  • UE 1205 handovers to AN 1207 and second UPF 1211.
  • UE 1205 now has a new IP address.
  • UE 1205 continues sending application messages with the anycast destination address.
  • routers in N6 IP network 1213 do not have flow state, but because EAS/LDN 1215 is the preferred address for the anycast destination address, packets are forwarded to EAS/LDN 1215.
  • Second UPF 1211 forwards the flow from UE 1205 that matches the flow 3-tuple with segment routing.
  • the application domain may initiate an edge relocation sequence at any point.
  • the edge application domain may change servers based on various criteria, such as, overload, site failure, DDoS attach mitigation, configured policies, etc.
  • criteria such as, overload, site failure, DDoS attach mitigation, configured policies, etc.
  • For stateful applications there are costs associated with moving data and context, all of which may be managed by the application domain.
  • IP path information may provide a mechanism and signaling so that the AF can be aware of N6 path characteristics (in terms of available bandwidth, latency, congestion, etc.).
  • N6 path characteristics are used by the AF to determine if the AS should be re-selected.
  • AS handling stateful applications
  • the AF (a control plane entity) and the management plane selects the AS and informs other sub-systems, such as Layer 4 and Layer 7 load balancers in the LDN of the AS instance.
  • the AF subscribes to N6 path characteristics, as well as obtains other feedback, e.g., from firewalls, and intrusion detection system (IDS) on intrusion detection.
  • IDS intrusion detection system
  • AF->AS Subscribe AS events
  • the AF subscribes to AS events to obtain notifications on changes in UE IP address.
  • the AF may also obtain notifications on other information such as AS load, AS latency, AS congestion, etc.
  • the AF is considered as an external control plane entity that interacts with the 5GC.
  • the AF additionally represents the control plane of the edge application domain that also handles application policy, server re-selection, etc., in the application domain.
  • Figure 13 illustrates a flow diagram of example operations 1300 occurring in an AF participating in AS re-selection.
  • Operations 1300 may be indicative of operations occurring in an AF as the AF participates in AS re-selection utilizing N6 path
  • Operations 1300 begin with the AF selecting an AS (block 1305).
  • the AF and the management plane selects an AS for an application executing on a UE.
  • the AS may be selected in accordance with N6 path characteristics, as well as the location of the UE.
  • the AF subscribes to UE IP address changes (block 1307).
  • the AF subscribes to obtain notifications from the AS when the UE obtains a new IP address.
  • the AF may also obtain additional information, such as AS load, AS latency, AS congestion, etc.
  • the AF receives notification of UE IP address change (block 1309).
  • the notification of the UE IP address change may be received from the AS.
  • the AF re-selects the AS (block 1311).
  • the AS may utilize N6 path characteristics, along with other metrics (such as site load and policies) to determine AS re-selection. If the AF re-selects the AS, the AF sends a request with information the newly selected AS, the URL for the LDN of the newly selected AS (block 1313).
  • the AS and the newly selected AS replicate UE application data and context.
  • the AS sends a redirect request with the URL of the new LDN/AS.
  • UE applications should be capable of initiating application level messaging to the AS to indicate change of IP address.
  • the UPF when segment routing is used to assist in the selection or re selection of the AS, the UPF maintains the segment routing state on a per PDU basis for the slices and sessions needing the capability.
  • the UPF should be able to receive distributed routing protocols, such as IGP or BGP, and the segment routing list to AS/LDN.
  • the UPF should also be able to handle the segment routing layers in the protocol stack, e.g., SR-MPLS, SRv6, etc., and encapsulate PDU session requests destined for the AS or decapsulate segment routing packets from the AS.
  • Initial segment routing forwarding rules may be populated for PDU sessions if its network slice selection assistance information (NSSAI) characteristics or destination address matches the LDN. Subsequent forwarding for these PDU sessions use segment routing.
  • NSSAI network slice selection assistance information
  • the segment routing lists may be provided in N4 protocol messages during handover or UPF selection.
  • the SMF stores the segment routing lists of the PDU sessions whose NSSAI or destination address matches the LDNs. This may be provided to the SMF in the form of N4 notifications. During handovers, the segment routing list that is stored is provided to the new UPF in N4 updates.
  • the AF should be able to receive measurement and path telemetry information from the 5GC. Furthermore, the AF should be able to receive notifications from the AS on change of UE IP addresses. The AF may factor this information along with N6 path characteristics corresponding to the new UE IP address to determine if AS re-selection is needed.
  • the AS should be able to detect change of the UE IP address.
  • the AS does so when the AS observes that packets from the UE, for the same application context, have a different IP address.
  • the AS provides notifications to the AF in this instance.
  • the AS may be assumed to have other capabilities required for the handover of application context, i.e., replication of application data, and so on.
  • Figure 14 illustrates an example communication system 1400.
  • the system 1400 enables multiple wireless or wired users to transmit and receive data and other content.
  • the system 1400 may implement one or more channel access methods, such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal FDMA (OFDMA), single-carrier FDMA (SC-FDMA), or non-orthogonal multiple access (NOMA).
  • CDMA code division multiple access
  • TDMA time division multiple access
  • FDMA frequency division multiple access
  • OFDMA orthogonal FDMA
  • SC-FDMA single-carrier FDMA
  • NOMA non-orthogonal multiple access
  • the communication system 1400 includes electronic devices (ED) 1410a- 1410c, radio access networks (RANs) i42oa-t42ob, a core network 1430, a public switched telephone network (PSTN) 1440, the Internet 1450, and other networks 1460. While certain numbers of these components or elements are shown in Figure 14, any number of these components or elements may be included in the system 1400.
  • ED electronic devices
  • RANs radio access networks
  • PSTN public switched telephone network
  • the EDs i4ioa-i4toc are configured to operate or communicate in the system 1400.
  • the EDs i4ioa-i4toc are configured to transmit or receive via wireless or wired communication channels.
  • Each ED i4ioa-i4toc represents any suitable end user device and may include such devices (or may be referred to) as a user equipment or device (UE), wireless transmit or receive unit (WTRU), mobile station, fixed or mobile subscriber unit, cellular telephone, personal digital assistant (PDA), smartphone, laptop, computer, touchpad, wireless sensor, or consumer electronics device.
  • UE user equipment or device
  • WTRU wireless transmit or receive unit
  • PDA personal digital assistant
  • smartphone laptop, computer, touchpad, wireless sensor, or consumer electronics device.
  • the RANs i42oa-t42ob here include base stations 14703-1470b, respectively.
  • Each base station 14708-1470b is configured to wirelessly interface with one or more of the EDs i4ioa-i4toc to enable access to the core network 1430, the PSTN 1440, the Internet 1450, or the other networks 1460.
  • the base stations I470a-t470b may include (or be) one or more of several well-known devices, such as a base transceiver station (BTS), a Node-B (NodeB), an evolved NodeB (eNodeB), a Next Generation (NG) NodeB (gNB), a Home NodeB, a Home eNodeB, a site controller, an access point (AP), or a wireless router.
  • BTS base transceiver station
  • NodeB Node-B
  • eNodeB evolved NodeB
  • NG Next Generation
  • gNB Next Generation NodeB
  • a Home NodeB a Home eNodeB
  • AP access point
  • the EDs 14108-14100 are configured to interface and communicate with the Internet 1450 and may access the core network 1430, the PSTN 1440, or the other networks 1460.
  • the base station 1470a forms part of the RAN 1420a, which may include other base stations, elements, or devices.
  • the base station 1470b forms part of the RAN 1420b, which may include other base stations, elements, or devices.
  • Each base station 1470a- 1470b operates to transmit or receive wireless signals within a particular geographic region or area, sometimes referred to as a“cell.”
  • MIMO multiple-input multiple-output
  • the base stations 1470a- 1470b communicate with one or more of the EDs i4ioa-i4toc over one or more air interfaces 1490 using wireless communication links.
  • the air interfaces 1490 may utilize any suitable radio access technology.
  • the system 1400 may use multiple channel access functionality, including such schemes as described above.
  • the base stations and EDs implement 5G New Radio (NR), LTE, LTE-A, or LTE-B.
  • NR 5G New Radio
  • LTE Long Term Evolution
  • LTE-A Long Term Evolution
  • LTE-B Long Term Evolution-B
  • the RANs I420a-t420b are in communication with the core network 1430 to provide the EDs i4ioa-i4toc with voice, data, application, Voice over Internet Protocol (VoIP), or other services. Understandably, the RANs i42oa-t42ob or the core network 1430 may be in direct or indirect communication with one or more other RANs (not shown).
  • the core network 1430 may also serve as a gateway access for other networks (such as the PSTN 1440, the Internet 1450, and the other networks 1460).
  • some or all of the EDs i4ioa-i4toc may include functionality for communicating with different wireless networks over different wireless links using different wireless technologies or protocols. Instead of wireless communication (or in addition thereto), the EDs may communicate via wired communication channels to a service provider or switch (not shown), and to the Internet 1450.
  • Figure 14 illustrates one example of a communication system
  • the communication system 1400 could include any number of EDs, base stations, networks, or other components in any suitable configuration.
  • Figures 15A and 15B illustrate example devices that may implement the methods and teachings according to this disclosure.
  • Figure 15A illustrates an example ED 1510
  • Figure 15B illustrates an example base station 1570. These components could be used in the system 1400 or in any other suitable system.
  • the ED 1510 includes at least one processing unit 1500.
  • the processing unit 1500 implements various processing operations of the ED 1510.
  • the processing unit 1500 could perform signal coding, data processing, power control, input/output processing, or any other functionality enabling the ED 1510 to operate in the system 1400.
  • the processing unit 1500 also supports the methods and teachings described in more detail above.
  • Each processing unit 1500 includes any suitable processing or computing device configured to perform one or more operations.
  • Each processing unit 1500 could, for example, include a microprocessor, microcontroller, digital signal processor, field programmable gate array, or application specific integrated circuit.
  • the ED 1510 also includes at least one transceiver 1502.
  • the transceiver 1502 is configured to modulate data or other content for transmission by at least one antenna or NIC (Network Interface Controller) 1504.
  • the transceiver 1502 is also configured to demodulate data or other content received by the at least one antenna 1504.
  • Each transceiver 1502 includes any suitable structure for generating signals for wireless or wired transmission or processing signals received wirelessly or by wire.
  • Each antenna 1504 includes any suitable structure for transmitting or receiving wireless or wired signals.
  • One or multiple transceivers 1502 could be used in the ED 1510, and one or multiple antennas 1504 could be used in the ED 1510.
  • a transceiver 1502 could also be implemented using at least one transmitter and at least one separate receiver.
  • the ED 1510 further includes one or more input/output devices 1506 or interfaces (such as a wired interface to the Internet 1450).
  • the input/output devices 1506 facilitate interaction with a user or other devices (network communications) in the network.
  • Each input/output device 1506 includes any suitable structure for providing information to or receiving information from a user, such as a speaker, microphone, keypad, keyboard, display, or touch screen, including network interface communications.
  • the ED 1510 includes at least one memory 1508.
  • the memory 1508 stores instructions and data used, generated, or collected by the ED 1510.
  • the memory 1508 could store software or firmware instructions executed by the processing unit(s) 1500 and data used to reduce or eliminate interference in incoming signals.
  • Each memory 1508 includes any suitable volatile or non-volatile storage and retrieval device(s). Any suitable type of memory may be used, such as random access memory (RAM), read only memory (ROM), hard disk, optical disc, subscriber identity module (SIM) card, memory stick, secure digital (SD) memory card, and the like.
  • the base station 1570 includes at least one processing unit 1550, at least one transceiver 1552, which includes functionality for a transmitter and a receiver, one or more antennas 1556, at least one memory 1558, and one or more input/output devices or interfaces 1566.
  • a scheduler which would be understood by one skilled in the art, is coupled to the processing unit 1550. The scheduler could be included within or operated separately from the base station 1570.
  • the processing unit 1550 implements various processing operations of the base station 1570, such as signal coding, data processing, power control, input/output processing, or any other functionality.
  • the processing unit 1550 can also support the methods and teachings described in more detail above.
  • Each processing unit 1550 includes any suitable processing or computing device configured to perform one or more operations.
  • Each processing unit 1550 could, for example, include a microprocessor, microcontroller, digital signal processor, field programmable gate array, or application specific integrated circuit.
  • Each transceiver 1552 includes any suitable structure for generating signals for wireless or wired transmission to one or more EDs or other devices. Each transceiver 1552 further includes any suitable structure for processing signals received wirelessly or by wire from one or more EDs or other devices. Although shown combined as a transceiver 1552, a transmitter and a receiver could be separate components. Each antenna 1556 includes any suitable structure for transmitting or receiving wireless or wired signals. While a common antenna 1556 is shown here as being coupled to the transceiver 1552, one or more antennas 1556 could be coupled to the transceiver(s) 1552, allowing separate antennas 1556 to be coupled to the transmitter and the receiver if equipped as separate components.
  • Each memory 1558 includes any suitable volatile or non-volatile storage and retrieval device(s).
  • Each input/output device 1566 facilitates interaction with a user or other devices (network communications) in the network.
  • Each input/output device 1566 includes any suitable structure for providing information to or receiving/providing information from a user, including network interface communications.
  • FIG. 16 is a block diagram of a computing system 1600 that may be used for implementing the devices and methods disclosed herein.
  • the computing system can be any entity of UE, access network (AN), mobility management (MM), session management (SM), user plane gateway (UPGW), or access stratum (AS).
  • Specific devices may utilize all of the components shown or only a subset of the components, and levels of integration may vary from device to device.
  • a device may contain multiple instances of a component, such as multiple processing units, processors, memories, transmitters, receivers, etc.
  • the computing system 1600 includes a processing unit 1602.
  • the processing unit includes a central processing unit (CPU) 1614, memory 1608, and may further include a mass storage device 1604, a video adapter 1610, and an I/O interface 1612 connected to a bus 1620.
  • the bus 1620 may be one or more of any type of several bus architectures including a memory bus or memory controller, a peripheral bus, or a video bus.
  • the CPU 1614 may comprise any type of electronic data processor.
  • the memory 1608 may comprise any type of non-transitory system memory such as static random access memory (SRAM), dynamic random access memory (DRAM), synchronous DRAM (SDRAM), read-only memory (ROM), or a combination thereof.
  • SRAM static random access memory
  • DRAM dynamic random access memory
  • SDRAM synchronous DRAM
  • ROM read-only memory
  • the memory 1608 may include ROM for use at boot-up, and DRAM for program and data storage for use while executing programs.
  • the mass storage 1604 may comprise any type of non-transitory storage device configured to store data, programs, and other information and to make the data, programs, and other information accessible via the bus 1620.
  • the mass storage 1604 may comprise, for example, one or more of a solid state drive, hard disk drive, a magnetic disk drive, or an optical disk drive.
  • the video adapter 1610 and the I/O interface 1612 provide interfaces to couple external input and output devices to the processing unit 1602.
  • input and output devices include a display 1618 coupled to the video adapter 1610 and a mouse, keyboard, or printer 1616 coupled to the I/O interface 1612.
  • Other devices may be coupled to the processing unit 1602, and additional or fewer interface cards may be utilized.
  • a serial interface such as Universal Serial Bus (USB) (not shown) may be used to provide an interface for an external device.
  • USB Universal Serial Bus
  • the processing unit 1602 also includes one or more network interfaces 1606, which may comprise wired links, such as an Ethernet cable, or wireless links to access nodes or different networks.
  • the network interfaces 1606 allow the processing unit 1602 to communicate with remote units via the networks.
  • the network interfaces 1606 may provide wireless communication via one or more transmitters/transmit antennas and one or more receivers/ receive antennas.
  • the processing unit 1602 is coupled to a local-area network 1622 or a wide-area network for data processing and communications with remote devices, such as other processing units, the Internet, or remote storage facilities. It should be appreciated that one or more steps of the embodiment methods provided herein may be performed by corresponding units or modules.
  • a signal may be transmitted by a transmitting unit or a transmitting module.
  • a signal may be received by a receiving unit or a receiving module.
  • a signal may be processed by a processing unit or a processing module. Other steps may be performed by a participating unit or module, a selecting unit or module, a resolving unit or module, or a providing unit or module.
  • the respective units or modules may be hardware, software, or a combination thereof.
  • one or more of the units or modules may be an integrated circuit, such as field programmable gate arrays (FPGAs) or application-specific integrated circuits (ASICs).

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Mobile Radio Communication Systems (AREA)

Abstract

L'invention concerne un procédé mis en oeuvre par une fonction de plan de commande (CPF), comprenant la réception, à partir d'une première fonction de plan d'utilisateur (UPF) associée à un équipement utilisateur (UE), d'informations d'acheminement de segment (SR) et d'informations de flux, l'UE étant desservi par un premier noeud d'accès; la participation à une procédure de transfert intercellulaire, cette procédure de transfert intercellulaire comprenant le passage de l'UE d'un état desservi par le premier noeud d'accès à un état desservi par un second noeud d'accès; la sélection d'un second UPF conformément au second noeud d'accès desservant l'UE; et la fourniture, au second noeud d'accès et au second UPF, des informations SR et des informations de flux. Un autre procédé utilisant l'unidiffusion aléatoire globale pour sélectionner une instance de serveur initiale et un réacheminement subséquent vers une adresse d'unidiffusion aléatoire de groupe local/de défaillance représentant la même instance de serveur pour un acheminement optimal de services à états est également décrit.
PCT/US2020/059700 2019-11-08 2020-11-09 Procédés et appareil de gestion de mobilité WO2021016631A2 (fr)

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EP4199478A1 (fr) * 2021-04-02 2023-06-21 Tencent Technology (Shenzhen) Company Limited Procédé et appareil de commande de rapport, dispositif, support et produit programme d'ordinateur
WO2023185573A1 (fr) * 2022-03-28 2023-10-05 大唐移动通信设备有限公司 Procédé, appareil, et dispositif de traitement d'informations

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112969209A (zh) * 2021-02-20 2021-06-15 腾讯科技（深圳）有限公司 业务服务器的切换控制方法及装置、电子设备、存储介质
CN112969208A (zh) * 2021-02-20 2021-06-15 腾讯科技（深圳）有限公司 业务服务器的切换控制方法及装置、电子设备、存储介质
WO2022174725A1 (fr) * 2021-02-20 2022-08-25 腾讯科技（深圳）有限公司 Procédé et appareil de commande pour commutation de serveurs de services, dispositif électronique et support de stockage
EP4199478A1 (fr) * 2021-04-02 2023-06-21 Tencent Technology (Shenzhen) Company Limited Procédé et appareil de commande de rapport, dispositif, support et produit programme d'ordinateur
EP4199478A4 (fr) * 2021-04-02 2024-05-15 Tencent Tech Shenzhen Co Ltd Procédé et appareil de commande de rapport, dispositif, support et produit programme d'ordinateur
EP4072101A1 (fr) * 2021-04-06 2022-10-12 Nokia Technologies Oy Procédure de découverte de serveur d'applications de bordure améliorée
WO2023185573A1 (fr) * 2022-03-28 2023-10-05 大唐移动通信设备有限公司 Procédé, appareil, et dispositif de traitement d'informations

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