Integration of Network Service Header (NSH) and Segment Routing for Service Function Chaining (SFC)
draft-ietf-spring-nsh-sr-03
SPRING J. Guichard, Ed.
Internet-Draft Futurewei Technologies
Intended status: Standards Track J. Tantsura, Ed.
Expires: March 28, 2021 Apstra inc.
September 24, 2020
Integration of Network Service Header (NSH) and Segment Routing for
Service Function Chaining (SFC)
draft-ietf-spring-nsh-sr-03
Abstract
This document describes two application scenarios where Network
Service Header (NSH) and Segment Routing (SR) can be deployed
together to support Service Function Chaining (SFC) in an efficient
manner while maintaining separation of the service and transport
planes as originally intended by the SFC architecture.
In both scenarios, SR is responsible for steering packets between
SFFs along a given Service Function Path (SFP) while NSH is
responsible for maintaining the integrity of the service plane, the
SFC instance context, and any associated metadata.
These application scenarios demonstrate 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
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This Internet-Draft will expire on March 28, 2021.
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Internet-Draft NSH-SR SFC September 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-based Transport Tunnel . . . . . . . . 5
4. SR-based SFC with Integrated NSH Service Plane . . . . . . . 9
5. Encapsulation Details . . . . . . . . . . . . . . . . . . . . 11
5.1. NSH using SR-MPLS Transport . . . . . . . . . . . . . . . 11
5.2. NSH using SRv6 Transport . . . . . . . . . . . . . . . . 12
6. Security Considerations . . . . . . . . . . . . . . . . . . . 13
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13
7.1. UDP Port Number for NSH . . . . . . . . . . . . . . . . . 13
7.2. Protocol Number for NSH . . . . . . . . . . . . . . . . . 14
8. Contributing Authors . . . . . . . . . . . . . . . . . . . . 14
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 15
9.1. Normative References . . . . . . . . . . . . . . . . . . 15
9.2. Informative References . . . . . . . . . . . . . . . . . 16
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 17
1. Introduction
1.1. SFC Overview and Rationale
The dynamic enforcement of a service-derived, 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 in the context of mobile
network infrastructure, have shown their limitations, such as the
same redundant classification features must be supported by many SFs
to execute their function, some SFs are receiving traffic that they
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