The Use of Path Segment in SR Inter-domain Scenarios
draft-xiong-spring-path-segment-sr-inter-domain-00

• Status
• IESG evaluation record
• IESG writeups
• Email expansions
• History

• Versions
• 00

SPRING                                                        Quan Xiong
Internet-Draft                                               Greg Mirsky
Intended status: Standards Track                         ZTE Corporation
Expires: January 4, 2020                                  Weiqiang Cheng
                                                            China Mobile
                                                            July 3, 2019

          The Use of Path Segment in SR Inter-domain Scenarios
           draft-xiong-spring-path-segment-sr-inter-domain-00

Abstract

   This document discusses the inter-domain scenarios for SR-MPLS
   network and proposes the solution with the use of Path Segment.

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
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at https://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   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 January 4, 2020.

Copyright Notice

   Copyright (c) 2019 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (https://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Quan Xiong, et al.       Expires January 4, 2020                [Page 1]
Internet-DraThe Use of Path Segment in SR Inter-domain Scenar  July 2019

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Conventions used in this document . . . . . . . . . . . . . .   3
     2.1.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   3
     2.2.  Requirements Language . . . . . . . . . . . . . . . . . .   3
   3.  Path Segment for SR-MPLS Inter-domain . . . . . . . . . . . .   3
     3.1.  Inter-domain Path Segment . . . . . . . . . . . . . . . .   4
     3.2.  End-to-end Path Segment . . . . . . . . . . . . . . . . .   4
   4.  SR-MPLS Inter-domain Scenarios  . . . . . . . . . . . . . . .   5
     4.1.  Stitching Inter-domain with i-Path  . . . . . . . . . . .   5
     4.2.  Nesting Inter-domain with e-Path  . . . . . . . . . . . .   6
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .   7
   6.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   7
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   7
   8.  Normative References  . . . . . . . . . . . . . . . . . . . .   7
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   8

1.  Introduction

   Segment Routing (SR) leverages the source routing paradigm.  A node
   steers a packet through an SR Policy instantiated as an ordered list
   of instructions called "segments".  A segment can represent any
   instruction, topological or service based.  A segment can have a
   semantic local to an SR node or global within an SR domain.  SR
   supports per-flow explicit routing while maintaining per-flow state
   only at the ingress nodes of the SR domain.  Segment Routing can be
   instantiated on MPLS data plane which is referred to as SR-MPLS
   [I-D.ietf-spring-segment-routing-mpls].  SR-MPLS leverages the MPLS
   label stack to construct the SR path.

   [I-D.ietf-spring-mpls-path-segment] defines a Path Segment identifier
   to support bidirectional path correlation for transport network.  In
   multi-domain scenarios, the SR bidirectional end-to-end tunnel MAY be
   established with the use of Path Segments.  The SR-MPLS inter-domain
   models include the stitching and nesting inter-domain models.  Path
   Segment MAY be used to indicate the inter-domain path or the end-to-
   end path and correlate the inter-domain paths or end-to-end
   unidirectional paths.

   This document discusses the inter-domain scenarios for SR-MPLS
   networks and proposes the solution with the use of Path Segment for
   end-to-end bidirectional SR path.

Quan Xiong, et al.       Expires January 4, 2020                [Page 2]
Internet-DraThe Use of Path Segment in SR Inter-domain Scenar  July 2019

2.  Conventions used in this document

2.1.  Terminology

   ABR: Area Border Routers.  Routers used to connect two IGP areas