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