IGP Extensions for Segment Routing Service Segment
draft-lz-lsr-igp-sr-service-segments-04
LSR Working Group Yao. Liu
Internet-Draft Zheng. Zhang
Intended status: Standards Track ZTE Corporation
Expires: July 25, 2021 Yongqing. Zhu
China Telecom
January 21, 2021
IGP Extensions for Segment Routing Service Segment
draft-lz-lsr-igp-sr-service-segments-04
Abstract
This document defines extensions to the link-state routing protocols
(IS-IS and OSPF) in order to carry service segment information via
IGP.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Conventions used in this document . . . . . . . . . . . . . . 3
2.1. Requirements Language . . . . . . . . . . . . . . . . . . 3
2.2. Acronyms . . . . . . . . . . . . . . . . . . . . . . . . 4
3. IGP Extensions for Service Segments . . . . . . . . . . . . . 4
3.1. IS-IS Extensions . . . . . . . . . . . . . . . . . . . . 4
3.2. OSPFv2 and OSPFv3 Extensions . . . . . . . . . . . . . . 6
4. Security Considerations . . . . . . . . . . . . . . . . . . . 7
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8
6. References . . . . . . . . . . . . . . . . . . . . . . . . . 8
6.1. Normative References . . . . . . . . . . . . . . . . . . 8
6.2. Informative References . . . . . . . . . . . . . . . . . 9
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 9
1. Introduction
Segments are introduced in the SR architecture [RFC8402]. Segment
Routing (SR) allows for a flexible definition of end-to-end paths by
encoding paths as sequences of topological sub-paths, called
"segments".
Service Function Chaining (SFC) [RFC7665] provides support for the
creation of composite services that consist of an ordered set of
Service Functions (SF) that are to be applied to packets and/or
frames selected as a result of classification.
[I-D.ietf-spring-sr-service-programming] describes how a service can
be associated with a SID and how to achieve service funtion chaining
in SR-enabled MPLS and IPv6 networks. It also defines SR-aware and
SR-unaware services. For a SR-unaware service ,there has to be a SR
proxy handling the SR processing on behalf of the service .
[I-D.dawra-idr-bgp-ls-sr-service-segments] propose extensions to BGP-
LS for Service Chaining to distribute the service segment information
to SR Controller.
The reference network topology is shown in figure 1.
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SR-C
A----1----2----3----4----5----B
| |
| |
S1 S2
Figure 1: Network with Services
Node 1-5 are nodes capital of segment routing. A and B are two end
hosts. S1 is an SR-aware Service. S2 is an SR-unaware Service and
node 4 act as an SR proxy. The path from A to B needs to pass
through service function S1 and S2. SR Controller (SR-C) is capable
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