BGP Extensions of SR Policy for Composite Candidate Path
draft-li-idr-sr-policy-composite-path-00
Network Working Group H. Li
Internet-Draft M. Chen
Intended status: Standards Track C. Lin
Expires: August 6, 2021 H3C
February 2, 2021
BGP Extensions of SR Policy for Composite Candidate Path
draft-li-idr-sr-policy-composite-path-00
Abstract
Segment Routing is a source routing paradigm that explicitly
indicates the forwarding path for packets at the ingress node. An SR
Policy is associated with one or more candidate paths. A candidate
path is either dynamic, explicit or composite. This document defines
extensions to BGP to distribute SR policies carrying composite
candidate path information. So that composite candidate paths can be
installed when the SR policy is applied.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 2
3. Constituent SR Policy Attributes in SR Policy . . . . . . . . 3
3.1. Constituent SR Policy Sub-TLV . . . . . . . . . . . . . . 4
4. Operations . . . . . . . . . . . . . . . . . . . . . . . . . 5
5. Security Considerations . . . . . . . . . . . . . . . . . . . 5
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5
7. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 6
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 6
8.1. Normative References . . . . . . . . . . . . . . . . . . 6
8.2. Informative References . . . . . . . . . . . . . . . . . 6
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7
1. Introduction
Segment routing (SR) [RFC8402] is a source routing paradigm that
explicitly indicates the forwarding path for packets at the ingress
node. The ingress node steers packets into a specific path according
to the Segment Routing Policy (SR Policy) as defined in
[I-D.ietf-spring-segment-routing-policy]. In order to distribute SR
policies to the headend, [I-D.ietf-idr-segment-routing-te-policy]
specifies a mechanism by using BGP.
An SR Policy is associated with one or more candidate paths. A
composite candidate path acts as a container for grouping of SR
Policies. As described in section 2.2 in
[I-D.ietf-spring-segment-routing-policy], the composite candidate
path construct enables combination of SR Policies, each with explicit
candidate paths and/or dynamic candidate paths with potentially
different optimization objectives and constraints, for a load-
balanced steering of packet flows over its constituent SR Policies.
This document defines extensions to Border Gateway Protocol (BGP) to
distribute SR policies carrying composite candidate path information.
So that composite candidate paths can be installed when the SR policy
is applied.
2. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP
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