Segment Routing Policy Architecture
draft-ietf-spring-segment-routing-policy-03
SPRING Working Group C. Filsfils
Internet-Draft S. Sivabalan, Ed.
Intended status: Standards Track Cisco Systems, Inc.
Expires: November 13, 2019 D. Voyer
Bell Canada
A. Bogdanov
Google, Inc.
P. Mattes
Microsoft
May 12, 2019
Segment Routing Policy Architecture
draft-ietf-spring-segment-routing-policy-03.txt
Abstract
Segment Routing (SR) allows a headend node to steer a packet flow
along any path. Intermediate per-flow states are eliminated thanks
to source routing. The headend node steers a flow into an SR Policy.
The header of a packet steered in an SR Policy is augmented with an
ordered list of segments associated with that SR Policy. This
document details the concepts of SR Policy and steering into an SR
Policy.
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 [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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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 November 13, 2019.
Filsfils, et al. Expires November 13, 2019 [Page 1]
Internet-Draft SR Policy May 2019
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. SR Policy . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.1. Identification of an SR Policy . . . . . . . . . . . . . 4
2.2. Candidate Path and Segment List . . . . . . . . . . . . . 4
2.3. Protocol-Origin of a Candidate Path . . . . . . . . . . . 5
2.4. Originator of a Candidate Path . . . . . . . . . . . . . 5
2.5. Discriminator of a Candidate Path . . . . . . . . . . . . 6
2.6. Identification of a Candidate Path . . . . . . . . . . . 7
2.7. Preference of a Candidate Path . . . . . . . . . . . . . 7
2.8. Validity of a Candidate Path . . . . . . . . . . . . . . 7
2.9. Active Candidate Path . . . . . . . . . . . . . . . . . . 7
2.10. Validity of an SR Policy . . . . . . . . . . . . . . . . 9
2.11. Instantiation of an SR Policy in the Forwarding Plane . . 9
2.12. Priority of an SR Policy . . . . . . . . . . . . . . . . 9
2.13. Summary . . . . . . . . . . . . . . . . . . . . . . . . . 9
3. Segment Routing Database . . . . . . . . . . . . . . . . . . 10
4. Segment Types . . . . . . . . . . . . . . . . . . . . . . . . 11
4.1. Explicit Null . . . . . . . . . . . . . . . . . . . . . . 14
5. Validity of a Candidate Path . . . . . . . . . . . . . . . . 15
5.1. Explicit Candidate Path . . . . . . . . . . . . . . . . . 15
5.2. Dynamic Candidate Path . . . . . . . . . . . . . . . . . 16
6. Binding SID . . . . . . . . . . . . . . . . . . . . . . . . . 17
6.1. BSID of a candidate path . . . . . . . . . . . . . . . . 17
6.2. BSID of an SR Policy . . . . . . . . . . . . . . . . . . 17
6.3. Forwarding Plane . . . . . . . . . . . . . . . . . . . . 18
6.4. Non-SR usage of Binding SID . . . . . . . . . . . . . . . 19
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