BGP Request for Candidate Paths of SR TE Policies
draft-li-ldr-bgp-request-cp-sr-te-policy-02
Network Working Group Z. Li
Internet-Draft L. Li
Intended status: Standards Track Huawei
Expires: April 6, 2021 H. Chen
Futurewei
Y. Fan
Casa Systems
X. Liu
Volta Networks
L. Liu
Fujitsu
October 3, 2020
BGP Request for Candidate Paths of SR TE Policies
draft-li-ldr-bgp-request-cp-sr-te-policy-02
Abstract
An SR Policy is a set of candidate paths. The headend of an SR
Policy may learn multiple candidate paths for an SR Policy via a
number of different mechanisms, e.g., CLI, NetConf, PCEP, or BGP.
This document defines extensions to BGP for the headend to request
BGP speaker (controller) for advertising the candidate paths.
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].
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
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Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on April 6, 2021.
Li, et al. Expires April 6, 2021 [Page 1]
Internet-Draft BGP Trigger SR TE Policies October 2020
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Overview of BGP Request for SR-TE Paths . . . . . . . . . . . 3
4. BGP Request UPDATE Message . . . . . . . . . . . . . . . . . 4
4.1. Extention of SR Policy NLRI . . . . . . . . . . . . . . . 4
4.2. New SR Policy Sub-TLVs . . . . . . . . . . . . . . . . . 5
4.2.1. SR Path Attributes Sub-TLV . . . . . . . . . . . . . 5
4.2.2. Synchronization Sub-TLV . . . . . . . . . . . . . . . 6
4.2.3. Metric Sub-TLV . . . . . . . . . . . . . . . . . . . 8
4.2.4. Include Route Sub-TLV . . . . . . . . . . . . . . . . 9
4.2.5. Load Balance Sub-TLV . . . . . . . . . . . . . . . . 10
4.2.6. Request Parameter Sub-TLV . . . . . . . . . . . . . . 10
5. IANA . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
6. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 12
7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 12
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 12
8.1. Normative References . . . . . . . . . . . . . . . . . . 12
8.2. Informative References . . . . . . . . . . . . . . . . . 13
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 14
1. Introduction
An SR Policy defined in [I-D.ietf-spring-segment-routing-policy] is a
set of candidate paths. The headend of an SR Policy may be informed
by various means including: Configuration, PCEP [RFC8281] or BGP
[I-D.ietf-idr-segment-routing-te-policy]. All these mechanisms are
Controller initiated, but in some situations the headend may want to
pull a set of candidate paths from Controller rather than receive all
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