MPLS Entropy Block
draft-jiang-mpls-entropy-block-01

Document Type Active Internet-Draft (individual)
Authors He Jiang  , Bolin Nie  , Zhenning Zhao 
Last updated 2020-06-29
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Network Working Group                                         J. He, Ed.
Internet-Draft                                                    B. Nie
Intended status: Standards Track                                 Z. Zhao
Expires: January 1, 2021                                        Ericsson
                                                           June 30, 2020

                           MPLS Entropy Block
                   draft-jiang-mpls-entropy-block-01

Abstract

   Load balancing across MPLS networks requires entropy information to
   be carried in MPLS label stack and to be handled by the downstream
   Label Switching Routers.  This document describes the problems using
   existing approaches and introduces an approach to the solution.

Status of This Memo

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He, et al.               Expires January 1, 2021                [Page 1]
Internet-Draft             MPLS Entropy Block                  June 2020

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  Approach  . . . . . . . . . . . . . . . . . . . . . . . . . .   3
   4.  End-to-End Processing . . . . . . . . . . . . . . . . . . . .   3
     4.1.  Example 1 Entropy Block advertisement through signaling .   3
     4.2.  Example 2 Entropy Block advertisement through global
           configuration . . . . . . . . . . . . . . . . . . . . . .   4
   5.  Signaling for Entropy Block . . . . . . . . . . . . . . . . .   5
   6.  Issues  . . . . . . . . . . . . . . . . . . . . . . . . . . .   5
     6.1.  Anycast Segment . . . . . . . . . . . . . . . . . . . . .   5
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   6
   8.  Security Considerations . . . . . . . . . . . . . . . . . . .   6
   9.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   6
     9.1.  Normative References  . . . . . . . . . . . . . . . . . .   6
     9.2.  Informative References  . . . . . . . . . . . . . . . . .   7
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   7

1.  Introduction

   Traffic load balancing improves bandwidth utilization in MPLS
   networks.  The entropy information is required to be carried in MPLS
   label stack of each packet in the MPLS network, and to be handled
   along the path by Label Switching Routers (LSR) towards egress node.
   [RFC6790] provides a technique used in the MPLS data plane to provide
   entropy for load-balancing, using a combination of Entropy Label
   Indicator and Entropy Label.  [RFC6391] provides another technique
   used in the MPLS data plane while only serve for pseudowire based
   services.

   An LSR may have limitations in the number of labels it can push.  It
   may also have a limitation in the number of labels it can inspect
   when looking for entropy information.  The limitations become obvious
   for traffic-engineering applications such as Segment Routing
   [RFC8402] and Resource ReserVation Protocol-Traffic Engineering
   (RSVP-TE) [RFC3209].  Some proposals are discussed in [RFC8662].

   This document describes an approach to mitigate the limitations, by
   allocating a specific MPLS label block for entropy usage.  Thus the
   entropy information can be carried in the MPLS label stack and
   handled by the downstream LSRs.  It adds additional alternatives
   beyond those discussed in [RFC6790] section 2.  This single entropy
   label approach improves efficiency when compared with [RFC6790] which
   uses label pair (ELI/EL).  It also accommodates label location
   flexibility and service agnostic when compared with [RFC6391].
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