SR-TE Path Midpoint Protection
draft-hu-spring-segment-routing-proxy-forwarding-12
Network Working Group Z. Hu
Internet-Draft Huawei Technologies
Intended status: Standards Track H. Chen
Expires: April 26, 2021 Futurewei
J. Yao
Huawei Technologies
C. Bowers
Juniper Networks
Y. Zhu
China Telecom
October 23, 2020
SR-TE Path Midpoint Protection
draft-hu-spring-segment-routing-proxy-forwarding-12
Abstract
Segment Routing Traffic Engineering (SR-TE) supports explicit paths
using segment lists containing adjacency-SIDs, node-SIDs and binding-
SIDs. The current SR FRR such as TI-LFA provides fast re-route
protection for the failure of a node along a SR-TE path by the direct
neighbor or say point of local repair (PLR) to the failure. However,
once the IGP converges, the SR FRR is no longer sufficient to forward
traffic of the path around the failure, since the non-neighbors of
the failure will no longer have a route to the failed node. This
document describes a mechanism for fast re-route protection against
the failure of a SR-TE path after the IGP converges. It provides
fast re-route protection for an adjacency segment, a node segment and
a binding segment of the path.
Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119].
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Hu, et al. Expires April 26, 2021 [Page 1]
Internet-Draft SR-TE Midpoint Protection October 2020
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Proxy Forwarding . . . . . . . . . . . . . . . . . . . . . . 3
3. Extensions to IGP for Proxy Forwarding . . . . . . . . . . . 4
3.1. Extensions to OSPF . . . . . . . . . . . . . . . . . . . 4
3.1.1. Advertising Proxy Forwarding . . . . . . . . . . . . 4
3.1.2. Advertising Binding Segment . . . . . . . . . . . . . 7
3.2. Extensions to IS-IS . . . . . . . . . . . . . . . . . . . 10
3.2.1. Advertising Proxy Forwarding . . . . . . . . . . . . 10
3.2.2. Advertising Binding Segment . . . . . . . . . . . . . 12
4. Building Proxy Forwarding Table . . . . . . . . . . . . . . . 13
4.1. Advertising Proxy Forwarding . . . . . . . . . . . . . . 15
4.2. Building Proxy Forwarding Table . . . . . . . . . . . . . 15
5. Node Protection for Segment List . . . . . . . . . . . . . . 15
5.1. Next Segment is an Adjacency Segment . . . . . . . . . . 16
5.2. Next Segment is a Node Segment . . . . . . . . . . . . . 16
5.3. Next Segment is a Binding Segment . . . . . . . . . . . . 17
6. Security Considerations . . . . . . . . . . . . . . . . . . . 18
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 18
7.1. OSPFv2 . . . . . . . . . . . . . . . . . . . . . . . . . 18
7.2. OSPFv3 . . . . . . . . . . . . . . . . . . . . . . . . . 19
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