Segment Routing interworking with LDP
draft-ietf-spring-segment-routing-ldp-interop-09

Document Type Active Internet-Draft (spring WG)
Last updated 2017-09-29
Replaces draft-filsfils-spring-segment-routing-ldp-interop
Stream IETF
Intended RFC status Proposed Standard
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Stream WG state Submitted to IESG for Publication (wg milestone: Apr 2016 - Document inter-worki... )
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Network Working Group                                   C. Filsfils, Ed.
Internet-Draft                                           S. Previdi, Ed.
Intended status: Standards Track                             A. Bashandy
Expires: April 2, 2018                               Cisco Systems, Inc.
                                                             B. Decraene
                                                            S. Litkowski
                                                                  Orange
                                                      September 29, 2017

                 Segment Routing interworking with LDP
            draft-ietf-spring-segment-routing-ldp-interop-09

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 and service chain 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 drafts
   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

   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
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   material or to cite them other than as "work in progress."

Filsfils, et al.          Expires April 2, 2018                 [Page 1]
Internet-Draft           Segment Routing and LDP          September 2017

   This Internet-Draft will expire on April 2, 2018.

Copyright Notice

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   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  SR/LDP Ship-in-the-night coexistence  . . . . . . . . . . . .   3
     2.1.  MPLS2MPLS co-existence  . . . . . . . . . . . . . . . . .   5
     2.2.  IP2MPLS co-existence  . . . . . . . . . . . . . . . . . .   6
   3.  Migration from LDP to SR  . . . . . . . . . . . . . . . . . .   6
   4.  SR and LDP Interworking . . . . . . . . . . . . . . . . . . .   7
     4.1.  LDP to SR . . . . . . . . . . . . . . . . . . . . . . . .   8
       4.1.1.  LDP to SR Behavior  . . . . . . . . . . . . . . . . .   8
     4.2.  SR to LDP . . . . . . . . . . . . . . . . . . . . . . . .   8
       4.2.1.  SR to LDP Behavior  . . . . . . . . . . . . . . . . .  10
   5.  SR/LDP Interworking Use Cases . . . . . . . . . . . . . . . .  11
     5.1.  SR Protection of LDP-based Traffic  . . . . . . . . . . .  11
     5.2.  Eliminating Targeted LDP Session  . . . . . . . . . . . .  13
     5.3.  Guaranteed FRR coverage . . . . . . . . . . . . . . . . .  14
     5.4.  Inter-AS Option C, Carrier's Carrier  . . . . . . . . . .  15
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  16
   7.  Manageability Considerations  . . . . . . . . . . . . . . . .  16
     7.1.  SR and LDP co-existence . . . . . . . . . . . . . . . . .  16
     7.2.  SRMS Management . . . . . . . . . . . . . . . . . . . . .  16
     7.3.  Dataplane Verification  . . . . . . . . . . . . . . . . .  17
   8.  Security Considerations . . . . . . . . . . . . . . . . . . .  17
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