BGP Extension for SR-MPLS Entropy Label Position
draft-zhou-idr-bgp-srmpls-elp-01

Document Type Active Internet-Draft (individual)
Last updated 2020-08-21
Stream (None)
Intended RFC status (None)
Formats plain text 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)
IDR Working Group                                               Yao. Liu
Internet-Draft                                              Shaofu. Peng
Intended status: Standards Track                               ZTE Corp.
Expires: February 22, 2021                               August 21, 2020

            BGP Extension for SR-MPLS Entropy Label Position
                    draft-zhou-idr-bgp-srmpls-elp-01

Abstract

   This document proposed an extension for BGP to configure the entropy
   label position for SR-MPLS networks.

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 February 22, 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.

Liu & Peng              Expires February 22, 2021               [Page 1]
Internet-DrafBGP Extension for SR-MPLS Entropy Label Positio August 2020

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Entropy Labels in SR-MPLS Scenario with a Controller  . . . .   2
   3.  BGP Extensions  . . . . . . . . . . . . . . . . . . . . . . .   3
   4.  Operations  . . . . . . . . . . . . . . . . . . . . . . . . .   3
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   4
   6.  Normative References  . . . . . . . . . . . . . . . . . . . .   4
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   4

1.  Introduction

   Entropy Label(EL) [RFC6790]is a technology that can be used for load-
   balancing in Segment Routing (SR) MPLS.

   [RFC8662] proposes to use entropy labels for SR-MPLS networks and
   mutiple < ELI, EL> pairs SHOULD be inserted in the SR-MPLS label
   stack.  The ingress node may decide the number and position of the
   ELI/ELs which need to be inserted into the label stack, that is
   termed as ELP (Entropy Label Position).  In some cases, the
   controller is used to perform the TE path computation for intra or
   inter-domain scenarios, thus it is also the responsibility of the
   controller to calculate ELP and inform it to the headend of the SR-TE
   path.

   [I-D.ietf-idr-segment-routing-te-policy] defines the specific process
   of how the controller in the SR network passes the path calculation
   result of the SR-TE policy to the headend of the network through BGP.

   In this document, the ELP information is transmitted by extending the
   flags of Segment List Sub-TLV in the BGP.

2.  Entropy Labels in SR-MPLS Scenario with a Controller

   [RFC8662] proposes to use entropy labels for SR-MPLS networks.  The
   Entropy Readable Label Depth (ERLD) is defined as the number of
   labels which means that the router will perform load-balancing using
   the ELI/EL.  An appropriate algorithm should consider the following
   criteria:

   o  a limited number of < ELI, EL> pairs SHOULD be inserted in the SR-
      MPLS label stack;

   o  the inserted positions SHOULD be whithin the ERLD of a maximize
      number of transit LSRs;

   o  a minimum number of < ELI, EL> pairs SHOULD be inserted while
      satisfying the above criteria.

Liu & Peng              Expires February 22, 2021               [Page 2]
Internet-DrafBGP Extension for SR-MPLS Entropy Label Positio August 2020

   As shown in Figure 1 , in SR-MPLS inter-domain scenario, the
   controller may perform the computation of the end-to-end path as well
   as the the Entropy Label Position (ELP) including the number and the
   position of the ELI/ELs.  The controller has the capability to get
   the ERLD information of all nodes in inter-domain scenarios.

    ....................   ....................    .....................
    .                  .   .                  .    .                   .
    .+---+       +---+ .   . +---+      +---+ .    .+---+      +----+  .
Show full document text