Integration of Network Service Header (NSH) and Segment Routing for Service Function Chaining (SFC)
draft-ietf-spring-nsh-sr-04

Document Type Active Internet-Draft (spring WG)
Authors Jim Guichard  , Jeff Tantsura 
Last updated 2020-12-11
Replaces draft-guichard-spring-nsh-sr
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SPRING                                                  J. Guichard, Ed.
Internet-Draft                                    Futurewei Technologies
Intended status: Standards Track                        J. Tantsura, Ed.
Expires: June 14, 2021                                       Apstra inc.
                                                       December 11, 2020

  Integration of Network Service Header (NSH) and Segment Routing for
                    Service Function Chaining (SFC)
                      draft-ietf-spring-nsh-sr-04

Abstract

   This document describes the integration of Network Service Header
   (NSH) [RFC8300] and Segment Routing (SR) [RFC8402], as well as
   encapsulation details, to support Service Function Chaining (SFC)
   [RFC7665] in an efficient manner while maintaining separation of the
   service and transport planes as originally intended by the SFC
   architecture.

   Combining these technologies allows SR to be used for steering
   packets between Service Function Forwarders (SFF) along a given
   Service Function Path (SFP) while NSH has the responsibility for
   maintaining the integrity of the service plane, the SFC instance
   context, and any associated metadata.

   The integration described in this document demonstrates that NSH and
   SR can work jointly and complement each other leaving the network
   operator with the flexibility to use whichever transport technology
   makes sense in specific areas of their network infrastructure, and
   still maintain an end-to-end service plane using NSH.

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
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   This Internet-Draft will expire on June 14, 2021.

Guichard & Tantsura       Expires June 14, 2021                 [Page 1]
Internet-Draft                 NSH-SR SFC                  December 2020

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  SFC Overview and Rationale  . . . . . . . . . . . . . . .   2
     1.2.  Requirements Language . . . . . . . . . . . . . . . . . .   3
   2.  SFC within Segment Routing Networks . . . . . . . . . . . . .   4
   3.  NSH-based SFC with SR-MPLS or SRv6 Transport Tunnel . . . . .   5
   4.  SR-based SFC with Integrated NSH Service Plane  . . . . . . .   9
   5.  Packet Processing Details . . . . . . . . . . . . . . . . . .  11
   6.  Encapsulation Details . . . . . . . . . . . . . . . . . . . .  11
     6.1.  NSH using SR-MPLS Transport . . . . . . . . . . . . . . .  11
     6.2.  NSH using SRv6 Transport  . . . . . . . . . . . . . . . .  12
   7.  Security Considerations . . . . . . . . . . . . . . . . . . .  14
   8.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  14
     8.1.  UDP Port Number for NSH . . . . . . . . . . . . . . . . .  14
     8.2.  Protocol Number for NSH . . . . . . . . . . . . . . . . .  15
     8.3.  SRv6 Endpoint Behavior for NSH  . . . . . . . . . . . . .  15
   9.  Contributing Authors  . . . . . . . . . . . . . . . . . . . .  15
   10. References  . . . . . . . . . . . . . . . . . . . . . . . . .  16
     10.1.  Normative References . . . . . . . . . . . . . . . . . .  16
     10.2.  Informative References . . . . . . . . . . . . . . . . .  18
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  18

1.  Introduction

1.1.  SFC Overview and Rationale

   The dynamic enforcement of a service-derived and adequate forwarding
   policy for packets entering a network that supports advanced Service
   Functions (SFs) has become a key challenge for network operators.
   Particularly, cascading SFs at the so-called Third Generation
   Partnership Project (3GPP) Gi interface (N6 interface in 5G
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