Internet DRAFT - draft-dunbar-cats-edge-service-metrics

draft-dunbar-cats-edge-service-metrics



Network Working Group                                   L. Dunbar
Internet Draft                                          Futurewei
Intended status: Standard                             K. Majumdar
Expires: January 6, 2024                              Microsoft
                                                       G. Mishra
                                                         H. Wang
                                                          Huawei
                                                         Verizon
                                                         H. Song
                                                       Futurewei
                                                     July 6, 2023

                     5G Edge Services Use Cases
             draft-dunbar-cats-edge-service-metrics-01

Abstract

   This draft describes the 5G Edge computing use cases for CATS
   and how BGP can be used to propagate additional IP layer
   detectable information about the 5G edge data centers so that
   the ingress routers in the 5G Local Data Network can make
   path selections based on not only the routing distance but
   also the IP Layer relevant metrics of the destinations. The
   goal is to improve latency and performance for 5G Edge
   Computing (EC) services even when the detailed servers
   running status are unavailable.

Status of this Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79. This document may not be
   modified, and derivative works of it may not be created,
   except to publish it as an RFC and to translate it into
   languages other than English.

   Internet-Drafts are working documents of the Internet
   Engineering Task Force (IETF), its areas, and its working
   groups.  Note that other groups may also distribute working
   documents as Internet-Drafts.





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Table of Contents


   1. Introduction..............................................3
   2. Conventions used in this document.........................3
   3. 5G Edge Computing Background..............................7
   4. Low Latency Service Instances Selection...................9
   5. Unbalanced Traffic Distribution by Mobility..............11
   6. 5G EC Service ID.........................................11
   7. Site Availability Index..................................11
   8. Site Preference Index....................................12
   9. Network Delay to an ANYCAST Address in 5G EC.............12
   10. Metrics for Predicting Service Delays...................13


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      10.1. Service Delay Prediction...........................14
      10.2. IP-Layer metrics for Service Delay Predication.....14
   11. Algorithm in Selecting the optimal Target Location......15
   12. Scope of Service Metrics Advertisement..................16
   13. Manageability Considerations............................17
   14. Security Considerations.................................17
   15. IANA Considerations.....................................17
   16. References..............................................17
      16.1. Normative References...............................17
      16.2. Informative References.............................18
   17. Acknowledgments.........................................18

1. Introduction

   This document describes the 5G Edge Computing use cases for
   CATS and how BGP can be used to propagate additional IP-layer
   relevant information about the destination so that the
   ingress routers in the 5G Local Data Network can make path
   selections based on not only the routing distance but also
   the IP Layer relevant metrics of the destinations. The goal
   is to improve latency and performance for 5G Edge Computing
   (EC) services even when the detailed servers running status
   are unavailable, as most applications and their hosting
   servers/VMs' detailed status are not exposed to network
   operators. Their communications are generally encrypted and
   do not respond to PING or ICMP messages initiated by routers
   or network elements.

   This draft specifies the IP Layer metrics and algorithms that
   enable the 5G Local Data Networks (LDN) to dynamically
   optimize the forwarding of low latency EC services without
   any knowledge above the IP layer.

2. Conventions used in this document

   CATS:       Computing-Aware Traffic Steering takes into
               account the dynamic nature of computing resource
               metrics and network state metrics to steer
               service traffic to a service instance.

   Service:    A monolithic function. A composite service can be
               built by orchestrating monolithic services.



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   Service instance: A run-time environment (e.g., a server or a
               process on a server) that makes the functionality
               of a service available. One service can have
               multiple instances running at the same or
               different network locations.

   CS-ID:      The CATS Service ID is an identifier representing
               a service, which the clients use to access said
               service. Such an identifier identifies all of the
               instances of the same service, no matter on where
               they are actually running. The CS-ID is
               independent of which service instance serves the
               service demand. Usually multiple instances
               provide a (logically) single service, and service
               demands are dispatched to the different instance
               by choosing one instance among all available
               instances.

   CB-ID:      The CATS Binding ID is an identifier of a single
               service instance of a given CS-ID. Different
               service instances provide the same service
               identified through a single CS-ID, but with
               different CATS Binding IDs.

   Service request: The request for a specific service instance.

   CATS-router: A network device (usually at the edge of the
               network) that makes forwarding decisions based on
               CATS information to steer traffic belonging to
               the same service demand to the same chosen
               service instance.

   Ingress CATS-Router: A network edge router that serves as a
               service access point for CATS clients. It steers
               the service packets onto an overlay path to an
               Egress CAN-Router linked to the most suitable
               edge site to access a service instance.

   CATS-ER:    CATS-ER is an egress CATS-Router, i.e., the
               egress endpoint of an overlay path to a service
               instance. CATS-ER is used to describe the last
               router that the service instances are attached.


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               In a 5G EC environment, the CATS-ER can be the
               gateway router to the Edge Computing Data Center.

   C-SMA:   The CATS Service Metric Agent responsible for
               collecting service capabilities and status, and
               for reporting them to the C-PS.

               NOTE: The above terminologies are the same as
               those used in 3GPP TR 23.758

   C-NMA:      The CATS Network Metric Agent responsible for
               collecting network capabilities and status, and
               for reporting them to the C-PS

   C-PS:       The CATS Path Selector determines the path toward
               the appropriate service location and service
               instances to meet a service demand given the
               service status and network status information.

   C-TC:       The CATS Traffic Classifier is responsible for
               determining which packets belong to a traffic
               flow for a particular service demand, and for
               steering them on the path to the service instance
               as determined by the C-PS.

   Edge DC:    Edge Data Center, which provides the Hosting
               Environment for the edge services. An Edge DC
               might host 5G core functions in addition to the
               frequently used application servers.

   gNB         next generation Node B

   PSA:        PDU Session Anchor (UPF)

   SSC:        Session and Service Continuity

   UE:         User Equipment

   UPF:        User Plane Function





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   ANYCAST Instance: refer to the service instance at a specific
               location which is reachable by the ANYCAST
               address.

   Service Instance Location: Represent a cluster of servers at
               one location serving the same Service. One
               service may have a Layer 7 Load balancer, whose
               address(es) are reachable from external IP
               network, in front of a set of service instances.
               From the IP network perspective, this whole group
               of instances are considered as one service
               instance at the location.

   EC:         Edge Computing

   Edge Computing Hosting Environment: An environment, such as
               psychical or virtual machines, host the service
               instances.

               NOTE: The above terminologies are the same as
               those used in 3GPP TR 23.758

   Edge DC:    Edge Data Center, which provides the Edge Hosting
               Environment. It might be co-located with 5G Base
               Station and not only host 5G core functions, but
               also host frequently used Edge server instances.



   LDN:        5G Local Data Network

   PSA:        PDU Session Anchor (UPF)

   RTT:        Round Trip Time

   RTT-ANYCAST:   A list of Round trip times to a group of
               routers that have the ANYCAST instances directly
               attached.


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   SSC:        Session and Service Continuity

   UE:         User Equipment

   UPF:        User Plane Function


   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL
   NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT
   RECOMMENDED", "MAY", and "OPTIONAL" in this document are to
   be interpreted as described in BCP 14 [RFC2119] [RFC8174]
   when, and only when, they appear in all capitals, as shown
   here.

3. 5G Edge Computing Background

   One of the 5G key features is the ultra-low latency services,
   which are enabled by instantiating one application or service
   in multiple edge data centers nearby [3GPP-EdgeComputing].
   Those Edge Computing (EC) mini data centers are usually very
   close to, or co-located with, 5G base stations to minimize
   the latency. The 5G Local Data Networks (LDN), a.k.a. N6
   interface from 3GPP 5G perspective, connect the edge data
   centers with the 5G User Plane Functions (UPF) with a small
   number of dedicated routers. The ultra-low latency 5G EC
   services are registered premium services that require super-
   low latency and very high SLA. Most UE service requests, such
   as internet browsing, are not part of the registered ultra-
   low latency services.

   When a UE (User Equipment) initiates the packets using the
   destination address from a DNS reply or its own cache, the
   packets from the UE are carried in a PDU session through the
   5G Core [5GC] to the 5G UPF-PSA (User Plan Function - PDU
   Session Anchor). The UPF-PSA decapsulates the 5G GTP outer
   header and forwards the packets from the UEs to the Ingress
   router of the 5G LDN. The LDN, the IP Network from 3GPP's 5G
   Core perspective, is responsible for forwarding the packets
   to the intended destinations.

   When the UE moves out of coverage of its current gNB (next-
   generation Node B) and anchors to a new gNB, the 5G SMF


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   (Session Management Function) could select the same UPF or a
   new UPF for the UE per standard handover procedures described
   in 3GPP TS 23.501 and TS 23.502. If the UE is anchored to a
   new UPF-PSA when the handover process is complete, the
   packets to/from the UE is carried by a GTP tunnel to the new
   UPF-PSA. Per TS 23.501-h20 Section 5.8.2, the UE may maintain
   its IP address when anchored to a new UPF-PSA unless the new
   UFP-PSA belongs to different mobile operators. 5GC may
   maintain a path from the old UPF to the new UPF for a short
   time for the SSC [Session and Service Continuity] mode 3 to
   make the handover process more seamless.
   +--+
   |UE|---\+---------+                 +------------------+
   +--+    |  5G     |  +-----------+  |  S1: aa08::4450  |
   +--+    | Site A +----+         +----+                 |
   |UE|----|        | Ra |         | R1 | S2: aa08::4460  |
   +--+    |        +----+         +----+                 |
   +---+   |         |  |           |  |  S3: aa08::4470  |
   |UE1|--/+---------+  |           |  +------------------+
   +---+                |IP Network |       L-DN1
                        |(3GPP N6)  |
     |                  |           |  +------------------+
     |                  |           |  |  S1: aa08::4450  |
     |                  |          +----+                 |
     |                  |          | R3 | S2: aa08::4460  |
     v                  |          +----+                 |
                        |           |  |  S3: aa08::4470  |
                        |           |  +------------------+
                        |           |      L-DN3
   +--+                 |           |
   |UE|---\+---------+  |           |  +------------------+
   +--+    |  5G     |  |           |  |  S1: aa08::4450  |
   +--+    | Site B +----+         +----+                 |
   |UE|----|        | Rb |         | R2 | S2: aa08::4460  |
   +--+    |        +----+         +----+                 |
   +--+    |         |  +-----------+  |  S3: aa08::4470  |
   |UE|---/+---------+                 +------------------+
   +--+                                     L-DN2
   Figure 1: multiple ANYCAST instances in different edge DCs





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4. Low Latency Service Instances Selection

   Having one application/service instantiated in multiple
   locations closer to UEs can greatly improve the user
   experience. But selecting an optimal location for the service
   requests from a UE may not be that simple.

   Using DNS to reply with the address of the service instance
   location closest to the requesting UE can encounter issues
   like:
     - UE can cache results indefinitely. When the UE moves to a
       5G cell site very far away, the cached address may still
       be used, which can incur a large network delay.
     - The service instance at a specific location, directed by
       the DNS, might be heavily loaded, causing slow or no
       response when there are available low utilized service
       instances for the same service at locations very close in
       proximity.
     - No inherent leverage of proximity information present in
       the network (routing) layer, resulting in performance
       loss.
     - Local DNS resolver becomes the unit of traffic
       management.

   Increasingly, ANYCAST is used to provide better and faster
   resiliency to failover events. Anycast address leverages the
   proximity information present in the network (routing) layer.
   It eliminates the single point of failure and bottleneck at
   the DNS resolvers. Anycast address can be assigned to
   instances in multiple data centers to leverage network
   conditions for balanced forwarding. Another benefit of using
   the ANYCAST address is removing the dependency on UEs
   refreshing their cached IP addresses.

   Using a Virtual IP address is another method to scale dynamic
   changes of application instances, a common practice in Cloud
   Native networking, e.g., Kubernetes. Virtual IP requires the
   destination gateway node to perform address translation for
   return traffic, which is unsuitable for underlay network
   nodes with millions of packets passing by.




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   Having multiple locations of the same IP address in the 5G EC
   LDN can be problematic if path selection is solely based on
   routing cost as the routing cost differences to reach
   different EC data centers can be very small. This list
   elaborates the issues in detail:
     - Path Selection: When a new flow comes to an ingress node
       (Ra in Figure 1), avoiding instability with ANYCAST
       flipping among paths to the same address can be an issue.
       The problem also exists in the BGP multipath environment,
       with the optimal path selected based on routing cost
       metrics.

       The ingress node needs to forward the packets from one
       flow to the same service instance, a.k.a. Flow Affinity
       or Flow-based load balancing.  The ingress node (Ra/Rb in
       Figure 1) can use Flow ID (in IPv6 header), or UDP/TCP
       port number combined with the source address to enforce
       packets in one flow being placed in one tunnel to one
       egress router.

     - When a UE moves to a new 5G site in the middle of a
       communication session with an EC service instance, a
       method is needed to stick the flow to the same EC service
       instance, which is required by 5G Edge Computing [3GPP TR
       23.748]. [5g-edge-compute-sticky-service] describes
       several approaches to achieve stickiness in the IPv6
       domain.

       Note: most EC services have shorter sessions, e.g.,
       shorter TCP sessions. Most likely, when a UE is moving to
       a new 5G site, the TCP session via the old UPF to an EC
       service instance is already finished. Only a very small
       percentage of registered EC services need to stick to the
       original service instance when handover to a new cell
       tower.

   From BGP perspective, the multiple service instances with the
   same IP address (ANYCAST)attached to different egress routers
   is the same as multiple next hops for the IP address.





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5. Unbalanced Traffic Distribution by Mobility

   It is common to have higher capacity EC service instances
   placed in a metro data center to accommodate more UEs in
   proximity and fewer placed in remote sites. Sometimes, UEs
   swarm to a specific site unexpectedly, e.g., a special event
   at a remote site for a short period, e.g., 1~2 days. The EC
   service instances in the remote site might be heavily
   utilized. In contrast, the EC service instances of the same
   app in the metro DC can be under-utilized. Since the
   condition can be short-lived or unexpected, it might not make
   business sense to adjust EC capacity among DCs.

6. 5G EC Service ID

   From the network perspective, a service identifier, or IP
   Layer Service ID, is an ANYCAST address shared by multiple
   service instances at different locations. Here are some
   assumptions about the 5G EC services:

     - Only the registered EC services, which are only a small
        portion of the services, need to incorporate the
        destination related metrics for optimal forwarding.

     - The 5G EC controller or management system can send those
        EC service identifiers to relevant routers.

     - The ingress routers' local BGP path compute algorithm
        has a special plugin that considers both the destination
        service metrics and traditional BGP path metrics in
        computing the path to the optimal Next Hop (egress
        router).

7. Site Availability Index

   Site Availability Index is a numeric number representing the
   percentage of the site being functional, e.g., 100%, 50%, or
   0%. When a site goes dark, the Index is set to 0.  50 means
   50% capacity functioning. When a data center goes dark (i.e.,
   the Site Availability index goes to 0 caused by a power
   outage), a large number of service instances are impacted.
   Instead of sending many BGP route withdrawal messages for



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   many address families impacted, the egress router can send
   one single message to indicate all the routes associated with
   a site are impacted. The ingress routers can switch all or a
   portion of the instances associated with the site depending
   on how much the site is degraded.

   Cloud Site/Pod failures and degradation can be caused by a
   variety of reasons, such as fiber cut connecting to the site
   or among pods within one site, cooling failures, insufficient
   backup power, cyber threats attacks, too many changes outside
   of the maintenance window, etc. Fiber-cut is not uncommon
   within a Cloud site or between sites.

   When those failure events happen, the Edge (egress) router
   visible to the ingress routers can be running fine.
   Therefore, the ingress routers with paths to the egress
   routers can't use BFD to detect the failures.

8. Site Preference Index

   As described in [IPv6-StickyService] and [ISPF-EXT-EC], an EC
   sticky service needs to connect a UE to the service instance
   that has been serving the UE before the UE moves to a new 5G
   Site unless there is a failure to that location.

   To achieve the goal of sticking a flow from one specific UE
   to a specific site, a "Site Preference Index" is created. The
   value of the Site Preference Index can be manipulated for
   packets of some flows to be steered towards an instance
   location farther away in routing distance. The "Site
   Preference Index" enables some sites to be more preferred for
   handling the UE traffic to an instance than others.

9. Network Delay to an ANYCAST Address in 5G EC

   ANYCAST used in 5G EC environment is slightly different from
   the typical ANYCAST address being deployed. Typical ANYCAST
   address is used to represent instances in vast different
   geographical locations, such as different continents. ANCAST
   address for "app.net" for Asia lead packets to a server
   instance of "app.net" hosted in Asia. Therefore, the RTT for
   "app.net" in Asia, is a single value that represent the round
   time trip to the server in Asia that host the "app.net".


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   5G EC can have one service hosted in multiple EC DCs close in
   proximity. Routers, i.e., the ingress router to 5G LDN, can
   forward packets for the ANYCAST address of "app.net" to
   different egress routers that have "app.net" instances
   attached.

   When "app.net" is hosted in four different 5G EC Data
   Centers, the RTT to "app.net" ANYCAST address need to be a
   group of values (instead of one RTT value to a unicast
   address). The RTT group value should include the CATS-ER
   router's specific unicast address (e.g., the loopback
   address) to which the service instance is attached.

   RTT to "app.net" ANYCAST Address is represented as:

       List of {Egress Router address, RTT value}

   This list is called "RTT-ANYCAST".

   In order to better optimize the ANYCAST traffic, each router
   adjacent to 5G PSA needs to periodically measure RTT to a
   list of CATS-ER routers that advertise the ANYCAST address.
   The RTT to egress router at Site-i is considered as the RTT
   to the ANYCAST instance at the Site-i.

10. Metrics for Predicting Service Delays

   It is desirable for an ingress router to select a path with
   the least network delay to an EC data center that has the
   shortest processing time for the service request from a UE
   for ultra-low latency services.  But it is not easy to
   predict which site has "the shortest processing time" for an
   incoming service request because EC data centers have
   different resources and different allocations of service
   instances to physical servers.

   The Service Delay Index is a value that predicts the
   processing delays at the site for future service requests.
   The higher the value, the longer the delay.







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 10.1. Service Delay Prediction

   Intuitively, an EC data center with more resources (e.g.,
   computing, storage, network bandwidth among servers) can
   process a service request faster than an EC data center with
   fewer resources.

   A Service Delay Predication value can be assigned to a site
   based on the relative resource level of the site, e.g., 1-
   100. A higher Service Delay Predication value means it might
   take a longer time to process an incoming service. The
   Service Delay Predication value is just an estimate, not
   meant to be accurate, even if the value can be adjusted based
   on the EC data center's actual running status.

 10.2. IP-Layer metrics for Service Delay Predication

   When EC data centers detailed running status is not exposed
   to the 5G LDN operator, historic traffic patterns through the
   LDNs can be utilized to anticipate or predict the load to a
   specific service. For example, when traffic volume to one
   service at one data center suddenly increases a huge
   percentage compared with the past 24 hours average, it is
   likely caused by a larger than normal number of UEs roaming
   to the same 5G site needing the service. When this happens,
   another EC data center with lower-than-average traffic volume
   for the same service might have a shorter processing time for
   the same service.

   Without knowledge of applications' internal logic, egress
   routers can measure the traffic patterns to/from the service
   instances at each location to predict the processing delay of
   the service at the location. Like the assigned processing
   delay value, processing delay prediction based on historic
   traffic patterns might not be accurate but at least reflect
   the current changes to the service request volume.










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   Here are some measurements that can be utilized to compute
   the Service Delay Predication for a service ID:

     - Total number of packets to the attached service instance
        (ToPackets);

     - Total number of packets from the attached service
        instance (FromPackets);

     - Total number of Bytes to the attached service instance
        (ToBytes);

     - Total number of bytes from the attached service instance
        (FromBytes);

   The actual load measurement to the service instance attached
   to a CATS-ER can be based on one of the metrics above or
   including all four metrics with different weights applied to
   each, such as:

   LoadIndex =
   w1*ToPackets+w2*FromPackes+w3*ToBytes+w4*FromBytes

          Where 0<= wi <=1 and w1+ w2+ w3+ w4 = 1.

   The weights of each metric contributing to the load index of
   the service instance attached to a CATS-ER can be configured
   or learned by self-adjusting based on user feedbacks.
   The Service Delay Prediction Index can be computed as
   LoadIndex/24Hour-Average. A higher value means a longer delay
   prediction.

11. Algorithm in Selecting the optimal Target Location

   The goal of the algorithm is to equalize the traffic among
   multiple locations of the same Service ID.

   This exemplary algorithm takes the following attributes into
   consideration to compare the cost to reach the service
   instances at Site-i vs. Site-j:

     -              Service Delay Predication (SerD-i) value,


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     - Capacity Availability index (CP-i)
     - Preference Index (Pref-i), and
     - network delay [NetD-i].

               SerD-i * CP-j               Pref-j * NetD-i
Cost-i=min(w *(----------------) + (1-w) *(------------------))
              SerD-j * CP-i               Pref-i * DetD-j


      w: Weight for load and site information, which is a value
      between 0 and 1. If smaller than 0.5, Network latency and
      the site Preference have more influence; otherwise, Server
      load and its capacity have more influence.

      When comparing metrics from Site-j with itself, the value
      from the algorithm is 1. Cost-i >1 indicates Site-i costs
      more than Site-j. Therefore, the shortest path to Site-j
      should be chosen.  Cost-i <1 indicates Site-i costs less
      than Site-j. Therefore, the shortest path to Site-i should
      be chosen.

12. Scope of Service Metrics Advertisement

   Each ultra-low latency EC service might be requested by a
   small group of UEs. Therefore, an egress router doesn't need
   to advertise the service metrics to all other routers in the
   5G LDN. Likewise, each EC Data Center may only host a small
   number of low-latency EC services.

   "Service ID Bound Group Routers" refers to a group of routers
   interested in a specific Service ID. The Service Metrics for
   a specific service ID should be advertised among the routers
   in the "Service ID bound Group Routers".














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   BGP RT Constrained Distribution [RFC4684] can be used to form
   the "Service ID Bound Group Routers" by using the "Service
   ID," which is an IP address prefix, as the Route Target. When
   an ingress router receives the first packet of a flow
   destined to a Service ID, the ingress router sends a BGP
   UPDATE that advertises the Route Target membership NLRI per
   RFC4684. The ingress router must assign a Timer for the
   Service ID as the UE that uses the Service ID might move
   away. Upon receiving a packet destined for the Service ID,
   the ingress router must refresh the Timer. The ingress router
   must send a BGP Withdraw UPDATE for the Service ID upon
   expiration of the Timer.

13. Manageability Considerations

     To be added.

14. Security Considerations


   To be added.

15. IANA Considerations

       To be added.

16. References


 16.1. Normative References

   [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
             Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC4364] E. rosen, Y. Rekhter, "BGP/MPLS IP Virtual Private
             networks (VPNs)", Feb 2006.

   [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in
             RFC 2119 Key Words", BCP 14, RFC 8174, DOI
             10.17487/RFC8174, May 2017, <https://www.rfc-
             editor.org/info/rfc8174>.



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                    5G Edge Service Use Cases

   [RFC8200] s. Deering R. Hinden, "Internet Protocol, Version 6
             (IPv6) Specification", July 2017


16.2. Informative References

   [3GPP-EdgeComputing] 3GPP TS 23.548 V18.1.1, "3rd Generation
             Partnership Project; Technical Specification Group
             Services and System Aspects; 5G System Enhancements
             for Edge Computing; Stage 2", Release 18, April
             2023.

   [SDWAN-EDGE-Discovery] L. Dunbar, S. Hares, R. Raszuk, K.
             Majumdar, "BGP UPDATE for SDWAN Edge Discovery",
             draft-ietf-idr-sdwan-edge-discovery-10, June 2023.

17. Acknowledgments

   Acknowledgements to XXX for their review and contributions.

   This document was prepared using 2-Word-v2.0.template.dot.


























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                    5G Edge Service Use Cases

Authors' Addresses


   Linda Dunbar
   Futurewei
   Email: ldunbar@futurewei.com

   Kausik Majumdar
   Microsoft
   Email: kmajumdar@microsoft.com

   Gyan Mishra
   Verizon
   Email: gyan.s.mishra@verizon.com

   Haibo Wang
   Huawei
   Email: rainsword.wang@huawei.com

   HaoYu Song
   Futurewei
   Email: haoyu.song@futurewei.com

























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