The Use of Path Segment in SR Inter-domain Scenarios
draft-xiong-spring-path-segment-sr-inter-domain-02

Document Type Active Internet-Draft (individual)
Last updated 2020-07-13
Stream (None)
Intended RFC status (None)
Formats plain text xml pdf htmlized (tools) htmlized bibtex
Stream Stream state (No stream defined)
Consensus Boilerplate Unknown
RFC Editor Note (None)
IESG IESG state I-D Exists
Telechat date
Responsible AD (None)
Send notices to (None)
SPRING                                                          Q. Xiong
Internet-Draft                                                 G. Mirsky
Intended status: Informational                           ZTE Corporation
Expires: January 14, 2021                                       W. Cheng
                                                            China Mobile
                                                           July 13, 2020

          The Use of Path Segment in SR Inter-domain Scenarios
           draft-xiong-spring-path-segment-sr-inter-domain-02

Abstract

   This document illustrates the inter-domain scenarios for SR-MPLS
   networks to support end-to-end bidirectional tunnel across multiple
   domains with the use of Path Segments.

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 14, 2021.

Copyright Notice

   Copyright (c) 2020 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.

Xiong, et al.           Expires January 14, 2021                [Page 1]
Internet-DraThe Use of Path Segment in SR Inter-domain Scenar  July 2020

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Conventions used in this document . . . . . . . . . . . . . .   3
     2.1.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   3
     2.2.  Requirements Language . . . . . . . . . . . . . . . . . .   3
   3.  End-to-end Path Segment . . . . . . . . . . . . . . . . . . .   4
     3.1.  S-PSID  . . . . . . . . . . . . . . . . . . . . . . . . .   4
     3.2.  N-PSID  . . . . . . . . . . . . . . . . . . . . . . . . .   4
   4.  SR-MPLS Inter-domain Scenarios  . . . . . . . . . . . . . . .   4
     4.1.  Stitching of Path Segments  . . . . . . . . . . . . . . .   5
     4.2.  Nesting of Path Segments  . . . . . . . . . . . . . . . .   6
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .   7
   6.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   7
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   8
   8.  Normative References  . . . . . . . . . . . . . . . . . . . .   8
   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.

   As defined in [RFC8402], the headend of an SR Policy binds a Binding
   Segment ID (B-SID) to its policy.  The B-SID could be bound to a SID
   List or selected path and used to stitch the SR list and the SR Label
   Switched Paths (LSP) across multiple domains.  In some scenarios, for
   example, a mobile backhaul transport network, it is required to
   provide end-to-end bidirectional path across SR networks.
   [I-D.ietf-spring-mpls-path-segment] defines a path segment identifier
   to support bidirectional path correlation for transport network.  In
   the multi-domain scenarios, the SR bidirectional end-to-end path MAY
   be established with the use of path segments.  Path segment MAY be
   used to indicate the end-to-end bidirectional path to achieve the
   path monitoring including nesting of Path Segments or Path SID
   (N-PSID) and stitching of Path Segments or Path SID (S-PSID).
Show full document text