Signaling Maximum SID Depth using Border Gateway Protocol Link-State
draft-tantsura-idr-bgp-ls-segment-routing-msd-00
IDR Working Group J. Tantsura
Internet-Draft G. Mirsky
Intended status: Standards Track Ericsson
Expires: September 10, 2016 S. Sivabalan
Cisco
U. Chunduri
Ericsson
March 9, 2016
Signaling Maximum SID Depth using Border Gateway Protocol Link-State
draft-tantsura-idr-bgp-ls-segment-routing-msd-00
Abstract
This document discusses use of BGP-LS to expose node and/or link on a
node MSD "Maximum SID Depth" to a centralized controller (PCE/SDN).
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Conventions used in this document . . . . . . . . . . . . 2
1.1.1. Terminology . . . . . . . . . . . . . . . . . . . . . 2
1.1.2. Requirements Language . . . . . . . . . . . . . . . . 3
2. Problem Statement . . . . . . . . . . . . . . . . . . . . . . 3
3. MSD supported by a node . . . . . . . . . . . . . . . . . . . 3
4. MSD supported on a link . . . . . . . . . . . . . . . . . . . 3
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4
6. Security Considerations . . . . . . . . . . . . . . . . . . . 4
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 4
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 4
8.1. Normative References . . . . . . . . . . . . . . . . . . 4
8.2. Informative References . . . . . . . . . . . . . . . . . 5
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 5
1. Introduction
When Segment Routing tunnels are computed by a centralized
controller, it is crucial that the controller knows MSD "Maximum SID
Depth" of the node or link SR tunnel exits over, so it doesn't
download a path with SID (label stack) of a depth more than the node
or link configured is capable of imposing.This document describes how
to use BGP-LS to expose the MSD of the node or link configured to a
centralized controller.
1.1. Conventions used in this document
1.1.1. Terminology
BGP-LS: Distribution of Link-State and TE Information using Border
Gateway Protocol
MSD: Maximum SID Depth
PCC: Path Computation Client
PCE: Path Computation Element
PCEP: Path Computation Element Protocol
SID: Segment Identifier
SR: Segment routing
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1.1.2. Requirements Language
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
[RFC2119].
2. Problem Statement
In existing technology only PCEP has extension to signal the MSD (SR
PCE Capability TLV/ METRIC Object as defined in
[I-D.ietf-pce-segment-routing],If PCEP is not supported by the node
(head-end of the SR tunnel) controller has no way to learn the MSD of
the node/link configured.
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