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Network Working Group                                              Z. Li
Internet-Draft                                                   S. Peng
Intended status: Standards Track                     Huawei Technologies
Expires: May 7, 2020                                            D. Voyer
                                                             Bell Canada
                                                                  C. Xie
                                                           China Telecom
                                                                  P. Liu
                                                            China Mobile
                                                                  C. Liu
                                                            China Unicom
                                                              K. Ebisawa
                                                Toyota Motor Corporation
                                                              S. Previdi
                                                              Individual
                                                             J. Guichard
                                             Futurewei Technologies Ltd.
                                                       November 04, 2019


  Problem Statement and Use Cases of Application-aware IPv6 Networking
                                 (APN6)
              draft-li-apn6-problem-statement-usecases-01

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.  However, network operators are typically unaware of which
   applications are traversing their network infrastructure, which means
   that only coarse-grained services can be provided to users.  As a
   result, network operators are only evolving their infrastructure to
   be large but dumb pipes without corresponding revenue increases that
   might be enabled by differentiated service treatment.  As network
   technologies evolve including deployments of IPv6 and SRv6, the
   programmability provided by IPv6 and SRv6 encapsulations can be
   augmented by conveying application related information into the
   network.  Adding application knowledge to the network layer allows
   applications to specify finer granularity requirements to the network
   operator.

   This document analyzes the existing problems caused by lack of
   application awareness, and outlines various use cases that could
   benefit from an Application-aware IPv6 Networking (APN6)
   architecture.



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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
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   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 May 7, 2020.

Copyright Notice

   Copyright (c) 2019 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
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   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.  Large but Dumb Pipe . . . . . . . . . . . . . . . . . . .   4
     3.2.  Network on Its Own  . . . . . . . . . . . . . . . . . . .   4
     3.3.  Decoupling of Network and Applications  . . . . . . . . .   4
     3.4.  Challenges of Traditional Differentiated Service
           Provisioning  . . . . . . . . . . . . . . . . . . . . . .   5



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     3.5.  Challenges of Supporting New 5G and Edge Computing
           Technologies  . . . . . . . . . . . . . . . . . . . . . .   6
   4.  Key Elements of Application-aware IPv6 Networking (APN6)  . .   6
   5.  Use cases for Application-aware IPv6 Networking (APN6)  . . .   8
     5.1.  Application-aware SLA Guarantee . . . . . . . . . . . . .   8
     5.2.  Application-aware network slicing . . . . . . . . . . . .   9
     5.3.  Application-aware Deterministic Networking  . . . . . . .   9
     5.4.  Application-aware Service Function Chaining . . . . . . .  10
     5.5.  Application-aware Network Measurement . . . . . . . . . .  10
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  11
   7.  Security Considerations . . . . . . . . . . . . . . . . . . .  11
   8.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  11
   9.  Contributors  . . . . . . . . . . . . . . . . . . . . . . . .  11
   10. References  . . . . . . . . . . . . . . . . . . . . . . . . .  12
     10.1.  Normative References . . . . . . . . . . . . . . . . . .  12
     10.2.  Informative References . . . . . . . . . . . . . . . . .  12
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  12

1.  Introduction

   Due to the requirement for differentiated traffic treatment driven by
   diverse new services, the ability to convey the characteristics of an
   application's traffic flow and program the network infrastructure
   accordingly to provide fine-grained service assurance is becoming
   increasingly necessary for network operators.  The Application-aware
   IPv6 Networking (APN6) architecture is being defined to address the
   requirements and use cases described in this document.  APN6 takes
   advantage of network programmability by conveying application related
   information in the data plane allowing applications to specify finer
   grained requirements to the network infrastructure.

2.  Terminology

   ACL: Access Control List

   APN6: Application-aware IPv6 Networking

   DPI: Deep Packet Inspection

   PBR: Policy Based Routing

   QoE: Quality of Experience

   SDN: Software Defined Networking







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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 application-awareness requirements demanded by
   new services that require differentiated service treatment.

3.1.  Large but Dumb Pipe

   In today's networks, the infrastructure through which user traffic is
   forwarded is not able to determine information about the packet,
   including which application the traffic belongs to, without the
   introduction of middleware such as DPI, that is, the network and
   applications are decoupled.  It is therefore difficult for network
   operators to provide fine-grained traffic operations for 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 (around 30%-40% of its capacity).
   This situation greatly increases the CAPEX and OPEX but only brings
   very little revenue from the carried services.

3.2.  Network on Its Own

   As the network evolves, technologies such as VPN/TE/FRR play
   important roles in satisfying service isolation, SLA guarantee, and
   high reliability, etc.  These network technologies have themselves
   been evolving, introducing new features that forces the network
   operator to be continuously upgrading their network infrastructure.
   However, none of these network technologies make the network aware of
   which application traffic belongs to and the fine granularity
   requirements of the application.  Therefore, such continuous network
   infrastructure upgrade doesn't always enable true fine-grained
   traffic operation, therefore reducing the ability to bring
   corresponding revenue increase.

3.3.  Decoupling of Network and Applications

   MPLS played a very important role in helping the network enter the
   generation of All-IP successfully.  However, MPLS doesn't allow a
   close interworking with the application layer since MPLS
   encapsulation is, typically, not used by the packet source.

   As new services continuously evolve, more encapsulations are
   required, and this isolation and decoupling has further become the
   blockage towards the seamless convergence of the network and
   applications.





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3.4.  Challenges of Traditional Differentiated Service Provisioning

   Several IETF activities have been reviewed which are primarily
   intended to evolve the IP architecture to support new service
   definitions which allow preferential or differentiated treatment to
   be accorded to certain types of traffic.  The challenge when using
   traditional ways to guarantee an SLA is that the packets are not able
   to carry enough information for indicating applications and
   expressing their service/SLA requirements.  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 information which needs to be translated in order to
   indicate a specific application.

   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 imposes security 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:

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

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






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

Figure 1. Many interfaces involved in the long service-provisioning loop

3.5.  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.

4.  Key Elements of Application-aware IPv6 Networking (APN6)

   Application-aware IPv6 Networking (APN6) aims to address the
   aforementioned problems 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.  APN6 conveys information into the
   network infrastructure about the characteristics of the application
   associated with a traffic flow (including application identification
   and network performance requirements), allowing the network to
   quickly adapt and perform the necessary network resource adjustments
   to maintain SLA performance guarantees, and hence better serve
   application fine-grained service requirements.

   The advantages of using IPv6 to support APN6 include,

   1.  Simplicity: Conveying application information with IPv6
       encapsulation can just be based on IP reachability.

   2.  Seamless convergence: Much easier to achieve seamless convergence
       between applications and network since both are based on IPv6.





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   3.  Great extensibility: IPv6 encapsulation including its extension
       headers can be used to carry very rich information relevant to
       applications.

   4.  Good compatibility: On-demand network upgrade and service
       provisioning.  If the application information is not recognized
       by the node, the packet will be forwarded based on pure IPv6,
       which ensure backward compatibility.

   5.  Little dependency: Information conveying and service provisioning
       are only based on the forwarding plane of devices, which is
       different from the Orchestration and SDN-based solution which
       involves multiple elements and diverse interfaces.

   6.  Quick response: Flow-driven and direct response from devices
       since it is based on the forwarding plane.

   APN6 has the following key elements:

   1.  Application information should be conveyed in the data plane
       through augmentation of existing encapsulations such as IPv6 and/
       or SRv6.  The conveyed application characteristic information
       (application-aware information) includes application
       identification and/or its network performance requirements.  This
       element should not be enforced but provide an open option for
       applications to decide whether to input this application-aware
       information into their data stream.

   2.  Application information and network service provisioning matching
       providing fine-granularity network service provisioning (traffic
       operations) and SLA guarantee based on the application-aware
       information carried in APN6 packets.  This element provides the
       network capabilities to applications.  According to the
       application-aware information, appropriate network services are
       selected, provisioned, and provided to the demanding applications
       to satisfy their performance requirements.

   3.  Network measurement of network performance and update the match
       between the applications and corresponding network services for
       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.








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             Applications         |          Network

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

   Figure 2. Illustration of the key elements of APN6

5.  Use cases for Application-aware IPv6 Networking (APN6)

   This section provides the use cases that can benefit from the
   application awareness introduced by APN6.  The corresponding
   requirements for APN6 are also outlined.

5.1.  Application-aware SLA Guarantee

   One of the key objectives of APN6 is for network operators to provide
   fine-granularity SLA guarantees instead of coarse-grain traffic
   operations.  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-level SLA
   guarantee.  Differentiated service provisioning is also desired.

   One of the key objective of APN6 is for network operators to provide
   fine-granularity SLA guarantees instead of coarse-grain traffic
   operations.  This will enable them to provide differentiated services
   for different applications and increase revenue accordingly.

   The APN6 architecture design MUST address the following requirements:

   o  APN6 needs to perform the three key elements as described in
      Section 4.

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







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5.2.  Application-aware network slicing

   More and more applications/services with diverse requirements are
   being carried over and sharing the network operators' network
   infrastructure.  However, it is still desirable to have customized
   network transport that can support some application's 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 APN6 architecture design MUST address the following requirements:

   o  APN6 needs to perform the three key elements as described in
      Section 4 in the context of network slicing.  To be more specific,
      for element 2, it needs to match to a specific network slice
      according to the application information carried in the APN6
      packets.  The network measurement in element 3 also needs to
      happen within each network slice.

5.3.  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 APN6 architecture design MUST address the following requirements:

   o  APN6 needs to perform the three key elements as described in
      Section 4 in the context of deterministic networking.  To be more
      specific, for the element 2, it needs to match to a specific
      deterministic path according to the application information
      carried in the APN6 packets.  The network measurement in element 3
      also needs to be performed on each application-aware deterministic
      path.







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5.4.  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 application traffic
   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 times.  For encrypted traffic,
   it even becomes impossible to inspect the application.

   The APN6 architecture design MUST address the following requirements:

   o  APN6 needs to perform the three key elements as described in
      Section 4 in the context of service function chaining.  To be more
      specific, for element 1 class information can be conveyed.  For
      element 2, it needs to match to a specific service function chain
      and subsequent steering according to the application information
      carried in the APN6 packets.  The network measurement in element 3
      also needs to happen within each app-aware service function chain.

5.5.  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
   the packet while the packet traverses a path between two points in
   the network.

   The APN6 architecture MUST address the following requirements:

   o  APN6 needs to perform the two key elements as described in
      Section 4 in the context of network measurement.  The network
      measurement in element 3 does not need to be considered here.








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6.  IANA Considerations

   This document does not include an IANA request.

7.  Security Considerations

   Since the application information is conveyed into the network, it
   does involve some security and privacy issues.

   First, APN6 only provides the capability to the applications to
   provide their profiles and requirements to the network, but it leaves
   the applications to decide whether to input this information.  If the
   applications decide not to provide any information, they will be
   treated in the same way as today's network and cannot get the
   benefits from APN6.

   Once the application information has been carried in the IPv6 packets
   and conveyed into the network, the IPv6 extension headers, AH and
   ESP, can be used to guarantee the authenticity of the added
   application information.

   Any scheme involving an information exchange between layers
   (application and network layers in this case) will obviously require
   an accurate valuation of security mechanism in order to prevent any
   leak of critical information.  Some additional considerations may be
   required for multi-domain use cases.  For example, how to agree upon
   which application information/ID to use and guarantee authenticity
   for packets traveling through multiple domains (network operators).

8.  Acknowledgements

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

9.  Contributors

   Liang Geng
   China Mobile
   China

   Email: gengliang@chinamobile.com

   Chang Cao
   China Unicom
   China

   Email: caoc15@chinaunicom.cn



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   Cong Li
   China Telecom
   China

   Email: licong.bri@chinatelecom.cn

10.  References

10.1.  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>.

   [RFC8200]  Deering, S. and R. Hinden, "Internet Protocol, Version 6
              (IPv6) Specification", STD 86, RFC 8200,
              DOI 10.17487/RFC8200, July 2017,
              <https://www.rfc-editor.org/info/rfc8200>.

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

10.2.  Informative References

   [I-D.ietf-6man-segment-routing-header]
              Filsfils, C., Dukes, D., Previdi, S., Leddy, J.,
              Matsushima, S., and d. daniel.voyer@bell.ca, "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., Camarillo, P., Leddy, J.,
              daniel.voyer@bell.ca, d., Matsushima, S., and Z. Li, "SRv6
              Network Programming", draft-ietf-spring-srv6-network-
              programming-05 (work in progress), October 2019.

Authors' Addresses







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   Zhenbin Li
   Huawei Technologies
   China

   Email: lizhenbin@huawei.com


   Shuping Peng
   Huawei Technologies
   China

   Email: pengshuping@huawei.com


   Daniel Voyer
   Bell Canada
   Canada

   Email: daniel.voyer@bell.ca


   Chongfeng Xie
   China Telecom
   China

   Email: xiechf.bri@chinatelecom.cn


   Peng Liu
   China Mobile
   China

   Email: liupengyjy@chinamobile.com


   Chang Liu
   China Unicom
   China

   Email: liuc131@chinaunicom.cn


   Kentaro Ebisawa
   Toyota Motor Corporation
   Japan

   Email: ebisawa@toyota-tokyo.tech




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   Stefano Previdi
   Individual
   Italy

   Email: stefano@previdi.net


   James N Guichard
   Futurewei Technologies Ltd.
   USA

   Email: jguichar@futurewei.com







































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