[Search] [txt|pdf|bibtex] [Tracker] [Email] [Diff1] [Diff2] [Nits]

Versions: 00 01 02 03 04                                                
Network Working Group                                              Z. Li
Internet-Draft                                                   S. Peng
Intended status: Standards Track                     Huawei Technologies
Expires: November 26, 2021                                      D. Voyer
                                                             Bell Canada
                                                                  C. Xie
                                                           China Telecom
                                                                  P. Liu
                                                            China Mobile
                                                                  Z. Qin
                                                            China Unicom
                                                               G. Mishra
                                                            Verizon Inc.
                                                              K. Ebisawa
                                                Toyota Motor Corporation
                                                              S. Previdi
                                                     Huawei Technologies
                                                             J. Guichard
                                             Futurewei Technologies Ltd.
                                                            May 25, 2021


 Problem Statement and Use Cases of Application-aware Networking (APN)
               draft-li-apn-problem-statement-usecases-03

Abstract

   Network operators are facing the challenge of providing better
   network services for users.  As the ever-developing 5G and industrial
   verticals evolve, more and more services that have diverse network
   requirements such as ultra-low latency and high reliability are
   emerging, and therefore differentiated service treatment is desired
   by users.  On the other hand, as network technologies such as
   Hierarchical QoS (H-QoS), SR Policy, and Network Slicing keep
   evolving, the network has the capability to provide more fine-
   granularity differentiated services.  However, network operators are
   typically unware of the applications that are traversing their
   network infrastructure, which means that not very effective
   differentiated service treatment can be provided to the traffic
   flows.  As network technologies evolve including deployments of IPv6,
   SRv6, Segment Routing over MPLS dataplane, the programmability
   provided by IPv6 and Segment Routing can be augmented by conveying
   application related information into the network satifying the fine-
   granularity requirements.

   This document analyzes the existing problems caused by lack of
   service awareness, and outlines various use cases that could benefit
   from an Application-aware Networking (APN) framework.



Li, et al.              Expires November 26, 2021               [Page 1]


Internet-Draft   Problem Statement and Use cases of APN         May 2021


Requirements Language

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in RFC 2119 [RFC2119].

Status of This Memo

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

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at https://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on November 26, 2021.

Copyright Notice

   Copyright (c) 2021 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (https://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  Problem Statement . . . . . . . . . . . . . . . . . . . . . .   4
     3.1.  Challenges of lack of fine-granularity service
           information . . . . . . . . . . . . . . . . . . . . . . .   4
     3.2.  Challenges of Traditional Differentiated Service
           Provisioning  . . . . . . . . . . . . . . . . . . . . . .   5
     3.3.  Challenges of Supporting New 5G and Edge Computing



Li, et al.              Expires November 26, 2021               [Page 2]


Internet-Draft   Problem Statement and Use cases of APN         May 2021


           Technologies  . . . . . . . . . . . . . . . . . . . . . .   6
   4.  Key Elements of Application-aware Networking (APN)  . . . . .   7
   5.  Scenarios of APN Domains  . . . . . . . . . . . . . . . . . .   8
   6.  Use cases for Application-aware Networking (APN)  . . . . . .  10
     6.1.  Application-aware SLA Guarantee . . . . . . . . . . . . .  10
     6.2.  Application-aware network slicing . . . . . . . . . . . .  11
     6.3.  Application-aware Deterministic Networking  . . . . . . .  11
     6.4.  Application-aware Service Function Chaining . . . . . . .  12
     6.5.  Application-aware Network Measurement . . . . . . . . . .  12
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  13
   8.  Security Considerations . . . . . . . . . . . . . . . . . . .  13
   9.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  13
   10. Contributors  . . . . . . . . . . . . . . . . . . . . . . . .  14
   11. References  . . . . . . . . . . . . . . . . . . . . . . . . .  14
     11.1.  Normative References . . . . . . . . . . . . . . . . . .  14
     11.2.  Informative References . . . . . . . . . . . . . . . . .  15
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  15

1.  Introduction

   Due to the requirement for differentiated traffic treatment driven by
   diverse new services, the ability to convey the application-aware
   information and program the network infrastructure accordingly to
   provide fine-grained services is becoming increasingly necessary for
   network operators.  The Application-aware Networking (APN) framework
   is being defined to address the requirements and use cases are
   described in this document.  APN takes advantage of network
   programmability by conveying application related information in the
   data plane to facilitate network operators to provide fine-grained
   services.

2.  Terminology

   ACL: Access Control List

   APN: Application-aware Networking

   APN6: Application-aware Networking for IPv6/SRv6

   DPI: Deep Packet Inspection

   PBR: Policy Based Routing

   QoE: Quality of Experience

   SDN: Software Defined Networking

   SLA: Service Level Agreement



Li, et al.              Expires November 26, 2021               [Page 3]


Internet-Draft   Problem Statement and Use cases of APN         May 2021


   MPLS: Multiprotocol Label Switching

   SR: Segment Routing

   SRv6: Segment Routing over IPv6 dataplane

   SR-MPLS: Segment Routing over MPLS dataplane

   VPN: Virtual Private Network

   TE: Traffic Engineering

   FRR: Fast Reroute

   CAPEX: Capital expenditures

   OPEX: Operating expenditures

3.  Problem Statement

   This section summarizes the challenges currently faced by network
   operators when attempting to provide fine-grained traffic operations
   to satisfy the various requirements demanded by new applications that
   require differentiated service treatment.

3.1.  Challenges of lack of fine-granularity service information

   In today's networks, the infrastructure through which the traffic is
   forwarded is not able to obtain the fine-granularity service
   information.  It is therefore difficult for network operators to
   provide fine-grained traffic operations for various performance-
   demanding applications.  In order to satisfy the SLA requirements
   network operators continue to increase the network bandwidth but only
   carrying very light traffic load (in general, around 30%-40% of its
   capacity).

   As network technologies keep evolving, the network capability has
   been greatly enhanced and is able to provide fine-granularity service
   provisioning.  For example,

   H-QoS: provides hierarchical fine-grained QoS services.

   SR Policy: provides the ability to handle a large number of explicit
   and flexible SR paths in order for services to select to satisfy
   their SLA requirements.






Li, et al.              Expires November 26, 2021               [Page 4]


Internet-Draft   Problem Statement and Use cases of APN         May 2021


   Network Slicing: provides the ability to define a number of network
   slices with guaranteed resources to satisfy highly demanding service
   requirements.

   IOAM: provides more accurate performance measurement of the traffic
   flow.

   In summary, driven by the ever-emerging diverse demanding services,
   the lack of the fine-granularity information about the services in
   the network will cause the following issues: 1) the service
   information is not clearly described and known by the network, 2) the
   fine-granularity service provisioning capability is not fully
   utilised, 3) a fine-granularity service scheduling and measurement
   cannot be achieved.

3.2.  Challenges of Traditional Differentiated Service Provisioning

   The traditional ways used to provide fine-grained service
   provisioning face some challenges.  The network devices mainly rely
   on the 5-tuple of the packets or DPI.  However, there are some
   challenges for these traditional methods in differentiated service
   provisioning:

   1.  Five Tuples used for ACL/PBR: five tuples are widely used for
       ACL/PBR matching of traffic.  However, these features cannot
       provide enough information for the fine-grained service process,
       and can only provide indirect application-level information which
       needs to be translated.  Generally, ACLs involve high overhead on
       the forwarding process.  Moreover, in some cases such as tunnel
       encapsulation and IPv6 data plane with a list of extension
       headers, it becomes impossible to resolve the 5 tuples due to the
       transport layer information being pushed very deep in the packet.

   2.  Deep Packet Inspection (DPI): If more information is needed, it
       must be extracted using DPI which can inspect deep into the
       packets for application specific information.  However, this will
       introduce more CAPEX and OPEX for the network operator and impose
       security and privacy challenges.

   3.  Orchestration and SDN-based Solution: In the era of SDN,
       typically, an SDN controller is used to manage and operate the
       network infrastructure and orchestrator elements introduce
       application requirements so that the network is programmed
       accordingly.  The SDN controller can be aware of the service
       requirements of the applications on the network through the
       interface with the orchestrator, and the service requirement is
       used by the controller for traffic management over the network.
       However, this method raises the following problems:



Li, et al.              Expires November 26, 2021               [Page 5]


Internet-Draft   Problem Statement and Use cases of APN         May 2021


       A.  The whole loop is long and time-consuming which is not
           suitable for fast service provisioning for critical
           applications;

       B.  Too many interfaces are involved in the loop, as shown in
           Figure 1, which introduce challenges of standardization and
           inter-operability.

                    +--------------+
              +-----| Orchestrator | -------------------+
              |     +--------------+   Resource         |
   APP Req.   |             |         Management        |
           +---------+  +---------+       &        +---------+
           |SDN Ctrl1|  |SDN Ctrl2|    Service     |SDN Ctrl3|
           +---------+  +---------+  Provisioning  +---------+
   App Req./    |        |       \                   |      \
          /     |        |        \                  |       \
         /      |        |         \                 |        \
    +---+   +-----+   +--------+  +-------+   +-------+  +-------+
    |APP|   | DCN |   |Network |..|Network|   |Network|..|Network|
    +---+   +-----+   |   D1   |  |   D3  |   |   D4  |  |   D6  |
                      +--------+  +-------+   +-------+  +-------+

        Figure 1: Multiple interfaces involved in the long service-
                             provisioning loop

   In [I-D.peng-apn-scope-gap-analysis], some mechanisms that have been
   specified in IETF and using attribute/identifier to perform traffic
   steering and service provisioning are analyzed.  The existing
   solutions are specific to a particular scenario or data plane, and a
   generalized method used for fine-grained service provisioning is
   still missing.

3.3.  Challenges of Supporting New 5G and Edge Computing Technologies

   New technologies such as 5G, IoT, and edge computing, are
   continuously developing leading to more and more new types of
   services accessing the network.  Large volumes of network traffic
   with diverse requirements such as low latency and high reliability
   are therefore rapidly increasing.  If traditional methods for
   differentiation of traffic continue to be utilized, it will cause
   much higher CAPEX and OPEX to satisfy the ever-developing
   applications' diverse requirements.








Li, et al.              Expires November 26, 2021               [Page 6]


Internet-Draft   Problem Statement and Use cases of APN         May 2021


4.  Key Elements of Application-aware Networking (APN)

   Application-aware Networking (APN) aims to address the problems
   mentioned in Section 3, associated with fine-grained traffic
   operations that are required in order to satisfy the various
   application-awareness requirements demanded by new services that need
   differentiated service treatment.

   In APN, the application-aware information (APN Attribute) is derived
   according to the existing information in the packet header and
   encapsulated along with the encapsulation of the tunnel.  With the
   APN attribute, fine-granularity network services can be provisioned
   within the APN domain accordingly.  The APN attribute can include
   application-aware ID (APN ID) and application-aware parameters (APN
   Parameters).  APN ID can be derived through the mapping from the
   existing information of the packet header and the APN parameters can
   be applied for the APN ID according to the local policy.  The typical
   APN parameters are the network performance requirements.

   APN has the following key elements:

   1.  Application-aware information (APN attribute) is conveyed in the
       data plane through augmentation of existing encapsulations such
       as IPv6, SRv6 and MPLS.  The conveyed APN attribute includes APN
       ID and/or APN parameters.  This information is acquired at the
       edge of the APN domain according to the existing information in
       the packet header.  When a data packet uses APN and conveys the
       application-aware information, it is referred in this document as
       an APN packet.

   2.  Application-aware information and network service provisioning
       matching providing fine-granularity network service provisioning
       (traffic operations) and SLA guarantee based on the APN attribute
       carried in APN packets.  According to the APN attribute,
       appropriate network services are selected, provisioned, and
       provided to the demanding applications to satisfy their service
       requirements.

   3.  Measurement of the network performance so to maintain the match
       between the applications requirements and corresponding network
       services for a better fine-granularity SLA compliance.  The
       network measurement methods include in-band and out-of-band,
       passive, active, per-packet, per-flow, per node, end-to-end, etc.
       These methods can also be integrated.







Li, et al.              Expires November 26, 2021               [Page 7]


Internet-Draft   Problem Statement and Use cases of APN         May 2021


                             APN Network

   Element 1: Conveying  ------------------->
                                 /|\
               APN attribute      |     Network capabilities
                                  |       (SLA guarantee)
                                  |             /|\
                         Element 2: Matching     |
                                                 |
                                        Element 3: Network Measurement

             Figure 2: Illustration of the key elements of APN

5.  Scenarios of APN Domains

   1.  SD-WAN scenario

   The SD-WAN scenario is shown in the following figure.  With APN, at
   the edge node, i.e. CPE, of the SD-WAN, the 5-tuple, plus information
   related to user or application group-level requirements is
   constructed into the APN attribute.  When the packet is sent from the
   CPE, the attribute is added along with the tunnel encapsulation.
   This attribute is only meaningful for the network operators to apply
   various policies in different nodes/service functions, which can be
   enforced from the Controllers.

                           +-----------------+
                 +---------|SD-WAN Controller|---------+
                 |         +--------|--------+         |
                 |                  |                  |
                 |          +-------|-------+          |
                 |          |SDN  Controller|          |
                 |          +-------|-------+          |
   +-----+       |                  |                  |      +-----+
   |App x|-\     |                  |                  |    /-|App x|
   +-----+ |  +--|--+   +-----------|-----------+   +--|--+ | +-----+
            \-|     |   |   Application-aware   |   |     |-/
              |CPE 1|---|        Network        |---|CPE 2|
            /-|     |   |  Service Provisioning |   |     |-\
   +-----+ |  +-----+   +-----------------------+   +-----+ | +-----+
   |App y|-/     |                                     |    \-|App y|
   +-----+       |<---         APN Domain          --->|      +-----+


               Figure 2. APN Domain in the Scenario of SD-WAN

   2.  Home broadband scenario




Li, et al.              Expires November 26, 2021               [Page 8]


Internet-Draft   Problem Statement and Use cases of APN         May 2021


   In the home broadband scenario, generally a home broadband user is
   authorized by the BNG.  If the validation is passed and the access
   control is released, so the user group can start enjoying the value-
   added service.  With APN, when the traffic traverses the metro
   network, the traffic flow can be indicated by the APN attribute that
   is added/removed at the edge devices of the Metro Network (APN
   domain) based on the mapping from the existing information (e.g. the
   QinQ which is composed of C-VLAN and S-VLAN) in the packet header and
   then carried in the tunnel encapsulation header.  The APN attribute
   will facilitate the fine-granular service in the APN domain.  Once
   the packets leave the APN domain, the APN attribute will be removed
   together with the tunnel encapsulation header.


                                |---- APN Domain ---|
    +----+                             .-----.
    | PC | \                          (       )
    +----+  \---\                 .--(         )--.
      +-----+    \+------+       (                 )       +-------+
      | STB |-----|  RG  |------(   Metro Network   )------|  BNG  |--->
      +-----+    /+------+       (                 )       +-------+
    +-----+ /---/                 '--(         )--'
    |Phone|/                          (       )
    +-----+                            '-----'
                            QinQ                     QinQ
                          |-----|----   Tunnel  ----|-----|


                    Figure 2.  Home Broadband Scenario

   3.  Mobile broadband scenario

   In the mobile broadband scenario, a UE is authorized by the 5GC
   function, and the traffic steering and QoS policy are enforced by the
   UPF (User Plane Function) node.  If the validation is passed and the
   access control is released, so the user can start enjoying the value-
   added service.  With APN, when the traffic traverses the mobile
   transport network, the traffic flow can be indicated by the APN
   attribute that is added at the edge devices of the mobile transport
   network (APN domain) based on mapping from the existing information
   (e.g.  GTP-u tunnel encapsulation information) in the packet header
   and then carried in the tunnel encapsulation header.  The APN
   attribute will facilitate the fine-granular service in the APN
   domain.  Once the packets leave the APN domain, the APN attribute
   will be removed together with the tunnel encapsulation header.  In
   fact, the APN attribute can also be acquired at the gNB based on the
   mapping of the existing information of the packet header (e.g.
   5-tuple information) and carried along with the GTP-u tunnel



Li, et al.              Expires November 26, 2021               [Page 9]


Internet-Draft   Problem Statement and Use cases of APN         May 2021


   encapsulation.  The mobile transport network can provide the
   corresponding service according to the APN attribute.  When the
   packet leaves the UPF, the APN attribute can be removed together with
   the GTP-u tunnel encapsulation.


                 |-----------        APN Domain        -----------|

    +----+                            .-----.
    | PC |                           (       )
    +----+                       .--(         )--.
      +----+     +------+       (                 )       +-------+
      | UE | --- | gNB  |------(  Mobile Transport )------|  UPF  |---->
      +----+     +------+       (     Network     )       +-------+
    +-----+                      '--(         )--'
    | CPE |                          (       )
    +-----+                           '-----'

                                |----  Tunnel  ----|

                     |---------      GTP-u Tunnel     --------|


                   Figure 3.  Mobile Broadband Scenario

6.  Use cases for Application-aware Networking (APN)

   This section illustrates some of the use cases that can benefit from
   APN.  The corresponding requirements for APN are also outlined.

6.1.  Application-aware SLA Guarantee

   One of the key objectives of APN is for network operators to provide
   fine-granularity SLA guarantees instead of coarse-grain traffic
   operations.  This will allow to provide differentiated services for
   different applications and increase revenue accordingly.  Among
   various applications being carried and running in the network, some
   revenue-producing applications such as online gaming, video
   streaming, and enterprise video conferencing have much more demanding
   performance requirements such as low network latency and high
   bandwidth.  In order to achieve better Quality of Experience (QoE)
   for end users and engage customers, the network needs to be able to
   provide fine-granularity and even application group-level SLA
   guarantee.  Differentiated service provisioning is also desired.

   The APN architecture MUST address the following requirements:





Li, et al.              Expires November 26, 2021              [Page 10]


Internet-Draft   Problem Statement and Use cases of APN         May 2021


   o  APN needs to perform the three key elements as described in
      Section 4.

   o  Support application group-level fine-granularity traffic operation
      that may include finer QoS scheduling.

6.2.  Application-aware network slicing

   More and more applications/services with diverse requirements are
   being carried over and sharing a common operators' network
   infrastructure.  However, it is still desirable to have customized
   network transport that can support some applications' specific
   requirements, taking into consideration service and resource
   isolation, which drives the concept of network slicing.

   Network slicing provides ways to partition the network infrastructure
   in either the control plane or data plane into multiple network
   slices that are running in parallel.  These network slices can serve
   diverse services and fulfill their various requirements at the same
   time.  For example, the mission critical application that requires
   ultra-low latency and high reliability can be provisioned over a
   separate network slice.

   The APN architecture MUST address the following requirements:

   o  APN needs to perform the three key elements as described in
      Section 4 in the context of network slicing.

   o  For the element 2, the APN architecture MUST allow to assign a
      given traffic flow to specific network slice according to the APN
      attribute carried in the APN packet.

   o  For the element 3, the APN architecture MUST allow the network
      measurement of each network slice.

6.3.  Application-aware Deterministic Networking

   [RFC8578] documents use cases for diverse industry applications that
   require deterministic flows over multi-hop paths.  Deterministic
   flows provide guaranteed bandwidth, bounded latency, and other
   properties relevant to the transport of time-sensitive data, and can
   coexist on an IP network with best-effort traffic.  It also provides
   for highly reliable flows through provision for redundant paths.

   The APN architecture MUST address the following requirements:

   o  APN needs to perform the three key elements as described in
      Section 4 in the context of deterministic networking.



Li, et al.              Expires November 26, 2021              [Page 11]


Internet-Draft   Problem Statement and Use cases of APN         May 2021


   o  For the element 2, the APN architecture MUST allow to assign a
      given traffic flow to a specific deterministic path according to
      the APN attribute carried in the APN packet.

   o  For the element 3, the APN architecture MUST allow the network
      measurement of each application-aware deterministic path.

6.4.  Application-aware Service Function Chaining

   End-to-end service delivery often needs to go through various service
   functions including traditional network service functions such as
   firewalls, DPIs as well as new application-specific functions, both
   physical and virtual.  The definition and instantiation of an ordered
   set of service functions and subsequent steering of the traffic
   through them is called Service Function Chaining (SFC) [RFC7665].
   SFC is applicable to both fixed and mobile networks as well as data
   center networks.

   Generally, in order to manipulate a specific traffic flow along the
   SFC, a DPI needs to be deployed as the first service function of the
   chain to detect the application, which will impose high CAPEX and
   consume long processing time.  For encrypted traffic, it even becomes
   impossible to inspect the traffic flow.

   The APN architecture MUST address the following requirements:

   o  APN needs to perform the three key elements as described in
      Section 4 in the context of service function chaining.

   o  For the element 1, class information can be conveyed.

   o  For the element 2, the APN architecture MUST allow to assign a
      given traffic flow to a specific service function chain and MUST
      allow the subsequent steering according to the APN attribute
      carried in the APN packets.

   o  For the element 3, the APN architecture MUST allow the network
      measurement of each application-aware service function chain.

6.5.  Application-aware Network Measurement

   Network measurement can be used for locating silent failure and
   predicting QoE satisfaction, which enables real-time SLA awareness/
   proactive OAM.  Operations, Administration, and Maintenance (OAM)
   refers to a toolset for fault detection and isolation, and network
   performance measurement.  In-situ Operations, Administration, and
   Maintenance (IOAM) records operational and telemetry information in




Li, et al.              Expires November 26, 2021              [Page 12]


Internet-Draft   Problem Statement and Use cases of APN         May 2021


   the packet while the packet traverses a path between two points in
   the network.

   The APN architecture MUST address the following requirements:

   o  APN needs to perform the two key elements as described in
      Section 4 in the context of network measurement.  The network
      measurement in the element 3 does not need to be considered here.

7.  IANA Considerations

   This document does not include an IANA request.

8.  Security Considerations

   In the APN work, in order to reduce the privacy and security issues,
   the APN attribute MUST be conveyed along with the tunnel information
   in the APN domain.  The APN attribute is encapsulated and removed at
   the edge of the APN domain.  The APN ID MUST be acquired from the
   existing available information in the packet header without
   interference into the payload.

   According to the above specifications, the APN attribute is only
   produced and used locally within the APN domain without the
   involvement of the host/application side.

   In order to prevent the malicious attack through the APN attribute,
   the following policies can be configured at the network devices of
   the APN domain.  If the APN attribute is conveyed without the tunnel
   information, the packet MUST be dropped.  If the APN attributes are
   not known to the APN domain, it should trigger the alarm information.
   The packet can be forwarded without being processed or dropped
   depending on the local policy.  If the network service requirements
   exceed the specification for the specific APN ID, it should trigger
   the alarm information.  The packet should be discarded to prevent
   abusing of the resources.  There should be rate-limiting policy at
   the edge of the APN domain to prevent the traffic belonging to a
   specific APN ID from exceeding the preset limit.

9.  Acknowledgements

   The authors would like to acknowledge Robert Raszuk (Bloomberg LP)
   and Yukito Ueno (NTT Communications Corporation) for their valuable
   review and comments.







Li, et al.              Expires November 26, 2021              [Page 13]


Internet-Draft   Problem Statement and Use cases of APN         May 2021


10.  Contributors

   Daniel Bernier
   Bell Canada
   Canada

   Email: daniel.bernier@bell.ca

   Liang Geng
   China Mobile
   China

   Email: gengliang@chinamobile.com

   Chang Cao
   China Unicom
   China

   Email: caoc15@chinaunicom.cn

   Chang Liu
   China Unicom
   China

   Email: liuc131@chinaunicom.cn

   Cong Li
   China Telecom
   China

   Email: licong@chinatelecom.cn

11.  References

11.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <https://www.rfc-editor.org/info/rfc2119>.

   [RFC7665]  Halpern, J., Ed. and C. Pignataro, Ed., "Service Function
              Chaining (SFC) Architecture", RFC 7665,
              DOI 10.17487/RFC7665, October 2015,
              <https://www.rfc-editor.org/info/rfc7665>.






Li, et al.              Expires November 26, 2021              [Page 14]


Internet-Draft   Problem Statement and Use cases of APN         May 2021


   [RFC8578]  Grossman, E., Ed., "Deterministic Networking Use Cases",
              RFC 8578, DOI 10.17487/RFC8578, May 2019,
              <https://www.rfc-editor.org/info/rfc8578>.

   [RFC8754]  Filsfils, C., Ed., Dukes, D., Ed., Previdi, S., Leddy, J.,
              Matsushima, S., and D. Voyer, "IPv6 Segment Routing Header
              (SRH)", RFC 8754, DOI 10.17487/RFC8754, March 2020,
              <https://www.rfc-editor.org/info/rfc8754>.

11.2.  Informative References

   [I-D.ietf-6man-segment-routing-header]
              Filsfils, C., Dukes, D., Previdi, S., Leddy, J.,
              Matsushima, S., and D. Voyer, "IPv6 Segment Routing Header
              (SRH)", draft-ietf-6man-segment-routing-header-26 (work in
              progress), October 2019.

   [I-D.ietf-spring-srv6-network-programming]
              Filsfils, C., Garvia, P. C., Leddy, J., Voyer, D.,
              Matsushima, S., and Z. Li, "Segment Routing over IPv6
              (SRv6) Network Programming", draft-ietf-spring-srv6-
              network-programming-28 (work in progress), December 2020.

   [I-D.peng-apn-scope-gap-analysis]
              Peng, S. and Z. Li, "APN Scope and Gap Analysis", draft-
              peng-apn-scope-gap-analysis-01 (work in progress),
              February 2021.

Authors' Addresses

   Zhenbin Li
   Huawei Technologies
   China

   Email: lizhenbin@huawei.com


   Shuping Peng
   Huawei Technologies
   China

   Email: pengshuping@huawei.com









Li, et al.              Expires November 26, 2021              [Page 15]


Internet-Draft   Problem Statement and Use cases of APN         May 2021


   Daniel Voyer
   Bell Canada
   Canada

   Email: daniel.voyer@bell.ca


   Chongfeng Xie
   China Telecom
   China

   Email: xiechf@chinatelecom.cn


   Peng Liu
   China Mobile
   China

   Email: liupengyjy@chinamobile.com


   Zhuangzhuang Qin
   China Unicom
   China

   Email: qinzhuangzhuang@chinaunicom.cn


   Gyan Mishra
   Verizon Inc.
   USA

   Email: gyan.s.mishra@verizon.com


   Kentaro Ebisawa
   Toyota Motor Corporation
   Japan

   Email: ebisawa@toyota-tokyo.tech


   Stefano Previdi
   Huawei Technologies
   Italy

   Email: stefano@previdi.net




Li, et al.              Expires November 26, 2021              [Page 16]


Internet-Draft   Problem Statement and Use cases of APN         May 2021


   James N Guichard
   Futurewei Technologies Ltd.
   USA

   Email: jguichar@futurewei.com














































Li, et al.              Expires November 26, 2021              [Page 17]