Network Service Header (NSH) and Segment Routing Integration for Service Function Chaining (SFC)
draft-ietf-spring-nsh-sr-02
SPRING J. Guichard, Ed.
Internet-Draft H. Song
Intended status: Standards Track Futurewei Technologies
Expires: October 8, 2020 J. Tantsura
Apstra inc.
J. Halpern
Ericsson
W. Henderickx
Nokia
M. Boucadair
Orange
S. Hassan
Cisco Systems
April 6, 2020
Network Service Header (NSH) and Segment Routing Integration for Service
Function Chaining (SFC)
draft-ietf-spring-nsh-sr-02
Abstract
This document describes two application scenarios where Network
Service Header (NSH) and Segment Routing (SR) techniques 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 the first scenario, an NSH-based SFC is created using SR as the
transport between Service Function Forwarders (SFFs). SR in this
case is just one of many encapsulations that could be used to
maintain the transport-independent nature of NSH-based service
chains.
In the second scenario, SR is used to represent each service hop of
the NSH-based SFC as a segment within the segment-list. SR and NSH
in this case are integrated.
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.
Guichard, et al. Expires October 8, 2020 [Page 1]
Internet-Draft NSH-SR SFC April 2020
Status of This Memo
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. SFC Overview and Rationale . . . . . . . . . . . . . . . 3
1.2. Requirements Language . . . . . . . . . . . . . . . . . . 4
1.3. SFC within SR Networks . . . . . . . . . . . . . . . . . 4
2. NSH-based SFC with SR-based Transport Tunnel . . . . . . . . 5
3. SR-based SFC with Integrated NSH Service Plane . . . . . . . 9
4. Encapsulation Details . . . . . . . . . . . . . . . . . . . . 11
4.1. NSH using MPLS-SR Transport . . . . . . . . . . . . . . . 11
4.2. NSH using SRv6 Transport . . . . . . . . . . . . . . . . 12
5. Security Considerations . . . . . . . . . . . . . . . . . . . 13
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13
6.1. UDP Port Number for NSH . . . . . . . . . . . . . . . . . 13
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