Segment Routing interworking with LDP
draft-ietf-spring-segment-routing-ldp-interop-15
Network Working Group A. Bashandy, Ed.
Internet-Draft Individual
Intended status: Standards Track C. Filsfils, Ed.
Expires: March 6, 2019 S. Previdi
Cisco Systems, Inc.
B. Decraene
S. Litkowski
Orange
September 02, 2018
Segment Routing interworking with LDP
draft-ietf-spring-segment-routing-ldp-interop-15
Abstract
A Segment Routing (SR) node steers a packet through a controlled set
of instructions, called segments, by prepending the packet with an SR
header. A segment can represent any instruction, topological or
service-based. SR allows to enforce a flow through any topological
path while maintaining per-flow state only at the ingress node to the
SR domain.
The Segment Routing architecture can be directly applied to the MPLS
data plane with no change in the forwarding plane. This document
describes how Segment Routing operates in a network where LDP is
deployed and in the case where SR-capable and non-SR-capable nodes
coexist.
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
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Bashandy, et al. Expires March 6, 2019 [Page 1]
Internet-Draft Segment Routing and LDP September 2018
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material or to cite them other than as "work in progress."
This Internet-Draft will expire on March 6, 2019.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. SR/LDP Ships-in-the-night coexistence . . . . . . . . . . . . 3
2.1. MPLS2MPLS, MPLS2IP and IP2MPLS co-existence . . . . . . . 5
3. SR and LDP Interworking . . . . . . . . . . . . . . . . . . . 6
3.1. LDP to SR . . . . . . . . . . . . . . . . . . . . . . . . 7
3.1.1. LDP to SR Behavior . . . . . . . . . . . . . . . . . 7
3.2. SR to LDP . . . . . . . . . . . . . . . . . . . . . . . . 7
3.2.1. Segment Routing Mapping Server (SRMS) . . . . . . . . 9
3.2.2. SR to LDP Behavior . . . . . . . . . . . . . . . . . 10
3.2.3. Interoperability of Multiple SRMSes and Prefix-SID
advertisements . . . . . . . . . . . . . . . . . . . 11
4. SR/LDP Interworking Use Cases . . . . . . . . . . . . . . . . 12
4.1. SR Protection of LDP-based Traffic . . . . . . . . . . . 12
4.2. Eliminating Targeted LDP Session . . . . . . . . . . . . 14
4.3. Guaranteed FRR coverage . . . . . . . . . . . . . . . . . 15
4.4. Inter-AS Option C, Carrier's Carrier . . . . . . . . . . 17
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 17
6. Manageability Considerations . . . . . . . . . . . . . . . . 17
6.1. SR and LDP co-existence . . . . . . . . . . . . . . . . . 17
6.2. Dataplane Verification . . . . . . . . . . . . . . . . . 18
7. Security Considerations . . . . . . . . . . . . . . . . . . . 18
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 18
9. Contributors' Addresses . . . . . . . . . . . . . . . . . . . 19
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 19
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