Path Segment in MPLS Based Segment Routing Network
draft-ietf-spring-mpls-path-segment-00
Network Working Group W. Cheng
Internet-Draft H. Li
Intended status: Standards Track China Mobile
Expires: September 9, 2019 M. Chen
Huawei
R. Gandhi
Cisco Systems, Inc.
R. Zigler
Broadcom
March 08, 2019
Path Segment in MPLS Based Segment Routing Network
draft-ietf-spring-mpls-path-segment-00
Abstract
A Segment Routing (SR) path is identified by an SR segment list, one
or partial segments of the list cannot uniquely identify the SR path.
Path identification is a pre-requisite for various use-cases such as
performance measurement (PM) of an SR path.
This document defines a new type of segment that is referred to as
Path Segment, which is used to identify an SR path. When used, it is
inserted at the ingress node of the SR path and immediately follows
the last segment of the SR path. The Path Segment will not be popped
off until it reaches the egress node of the SR path.
Path Segment can be used by the egress node to implement path
identification hence to support various use-cases including SR path
PM, end-to-end 1+1 SR path protection and bidirectional SR paths
correlation.
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Cheng, et al. Expires September 9, 2019 [Page 1]
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 3
1.2. Abbreviations . . . . . . . . . . . . . . . . . . . . . . 3
2. Path Segment . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Nesting of Path Segments . . . . . . . . . . . . . . . . . . 5
4. Path Segment Allocation . . . . . . . . . . . . . . . . . . . 6
5. Path Segment for PM . . . . . . . . . . . . . . . . . . . . . 6
6. Path Segment for Bi-directional SR Path . . . . . . . . . . . 7
7. Path Segment for End-to-end Path Protection . . . . . . . . . 7
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8
9. Security Considerations . . . . . . . . . . . . . . . . . . . 8
10. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 8
11. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 8
12. References . . . . . . . . . . . . . . . . . . . . . . . . . 9
12.1. Normative References . . . . . . . . . . . . . . . . . . 9
12.2. Informative References . . . . . . . . . . . . . . . . . 9
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 10
1. Introduction
Segment Routing (SR) [RFC8402] is a source routed forwarding method
that allows to directly encode forwarding instructions (called
segments) in each packet, hence it enables to steer traffic through a
network without the per-flow states maintained on the transit nodes.
Segment Routing can be instantiated on MPLS data plane or IPv6 data
plane. The former is called SR-MPLS, the latter is called SRv6
[RFC8402]. SR-MPLS leverages the MPLS label stack to construct SR
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