Signaling Entropy Label Capability and Entropy Readable Label Depth Using IS-IS
draft-ietf-isis-mpls-elc-09

Document Type Active Internet-Draft (lsr WG)
Last updated 2019-10-04
Replaces draft-xu-isis-mpls-elc
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Intended RFC status Proposed Standard
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Network Working Group                                              X. Xu
Internet-Draft                                               Alibaba Inc
Intended status: Standards Track                                 S. Kini
Expires: April 6, 2020
                                                               P. Psenak
                                                             C. Filsfils
                                                            S. Litkowski
                                                                   Cisco
                                                         October 4, 2019

  Signaling Entropy Label Capability and Entropy Readable Label Depth
                              Using IS-IS
                      draft-ietf-isis-mpls-elc-09

Abstract

   Multiprotocol Label Switching (MPLS) has defined a mechanism to load-
   balance traffic flows using Entropy Labels (EL).  An ingress Label
   Switching Router (LSR) cannot insert ELs for packets going into a
   given Label Switched Path (LSP) unless an egress LSR has indicated
   via signaling that it has the capability to process ELs, referred to
   as Entropy Label Capability (ELC), on that tunnel.  In addition, it
   would be useful for ingress LSRs to know each LSR's capability for
   reading the maximum label stack depth and performing EL-based load-
   balancing, referred to as Entropy Readable Label Depth (ERLD).  This
   document defines a mechanism to signal these two capabilities using
   IS-IS.  These mechanisms are particularly useful, where label
   advertisements are done via protocols like IS-IS.

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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   This Internet-Draft will expire on April 6, 2020.

Xu, et al.                Expires April 6, 2020                 [Page 1]
Internet-Draft     Signaling ELC and ERLD using IS-IS       October 2019

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
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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  Advertising ELC Using IS-IS . . . . . . . . . . . . . . . . .   3
   4.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   4
   5.  Advertising ERLD Using IS-IS  . . . . . . . . . . . . . . . .   4
   6.  Signaling ELC and ERLD in BGP-LS  . . . . . . . . . . . . . .   4
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   5
   8.  Security Considerations . . . . . . . . . . . . . . . . . . .   5
   9.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   5
     9.1.  Normative References  . . . . . . . . . . . . . . . . . .   5
     9.2.  Informative References  . . . . . . . . . . . . . . . . .   6
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   7

1.  Introduction

   [RFC6790] describes a method to load-balance Multiprotocol Label
   Switching (MPLS) traffic flows using Entropy Labels (EL).  "The Use
   of Entropy Labels in MPLS Forwarding" [RFC6790] introduces the
   concept of Entropy Label Capability (ELC) and defines the signalings
   of this capability via MPLS signaling protocols.  Recently,
   mechanisms have been defined to signal labels via link-state Interior
   Gateway Protocols (IGP) such as IS-IS
   [I-D.ietf-isis-segment-routing-extensions].  In such scenarios, the
   defined signaling mechanisms are inadequate.  This draft defines a
   mechanism to signal the ELC using IS-IS.  This mechanism is useful
   when the label advertisement is also done via IS-IS.

   In addition, in the cases where LSPs are used for whatever reasons
   (e.g., SR-MPLS [I-D.ietf-spring-segment-routing-mpls]), it would be
   useful for ingress LSRs to know each intermediate LSR's capability of
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