Advertising Segment
Routing Policies in BGP
draft-ietf-idr-segment-routing-te-policy-08
Network Working Group S. Previdi
Internet-Draft Individual
Intended status: Standards Track C. Filsfils
Expires: May 21, 2020 K. Talaulikar, Ed.
Cisco Systems
P. Mattes
Microsoft
E. Rosen
Juniper Networks
D. Jain
S. Lin
Google
November 18, 2019
Advertising Segment Routing Policies in BGP
draft-ietf-idr-segment-routing-te-policy-08
Abstract
This document defines a new BGP SAFI with a new NLRI in order to
advertise a candidate path of a Segment Routing (SR) Policy. An SR
Policy is a set of candidate paths, each consisting of one or more
segment lists. The headend of an SR Policy may learn multiple
candidate paths for an SR Policy. Candidate paths may be learned via
a number of different mechanisms, e.g., CLI, NetConf, PCEP, or BGP.
This document specifies the way in which BGP may be used to
distribute SR Policy candidate paths. New sub-TLVs for the Tunnel
Encapsulation Attribute are defined for signaling information about
these candidate paths.
Status of This Memo
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material or to cite them other than as "work in progress."
This Internet-Draft will expire on May 21, 2020.
Previdi, et al. Expires May 21, 2020 [Page 1]
Internet-Draft Segment Routing Policies in BGP November 2019
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 5
2. SR Policy Encoding . . . . . . . . . . . . . . . . . . . . . 5
2.1. SR Policy SAFI and NLRI . . . . . . . . . . . . . . . . . 5
2.2. SR Policy and Tunnel Encapsulation Attribute . . . . . . 7
2.3. Remote Endpoint and Color . . . . . . . . . . . . . . . . 8
2.4. SR Policy Sub-TLVs . . . . . . . . . . . . . . . . . . . 8
2.4.1. Preference Sub-TLV . . . . . . . . . . . . . . . . . 9
2.4.2. Binding SID Sub-TLV . . . . . . . . . . . . . . . . . 9
2.4.3. Segment List Sub-TLV . . . . . . . . . . . . . . . . 11
2.4.4. Explicit NULL Label Policy Sub-TLV . . . . . . . . . 24
2.4.5. Policy Priority Sub-TLV . . . . . . . . . . . . . . . 25
2.4.6. Policy Name Sub-TLV . . . . . . . . . . . . . . . . . 26
3. Color Extended Community . . . . . . . . . . . . . . . . . . 27
4. SR Policy Operations . . . . . . . . . . . . . . . . . . . . 27
4.1. Advertisement of SR Policies . . . . . . . . . . . . . . 27
4.2. Reception of an SR Policy NLRI . . . . . . . . . . . . . 28
4.2.1. Acceptance of an SR Policy NLRI . . . . . . . . . . . 28
4.2.2. Usable SR Policy NLRI . . . . . . . . . . . . . . . . 29
4.2.3. Passing a usable SR Policy NLRI to the SRPM . . . . . 29
4.2.4. Propagation of an SR Policy . . . . . . . . . . . . . 29
5. Error Handling . . . . . . . . . . . . . . . . . . . . . . . 30
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 31
6.1. Existing Registry: Subsequent Address Family Identifiers
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