Signaling Entropy Label Capability and Entropy Readable Label Depth Using IS-IS
draft-ietf-isis-mpls-elc-07

Document Type Active Internet-Draft (lsr WG)
Last updated 2019-05-14
Replaces draft-xu-isis-mpls-elc
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Network Working Group                                              X. Xu
Internet-Draft                                               Alibaba Inc
Intended status: Standards Track                                 S. Kini
Expires: November 15, 2019
                                                               P. Psenak
                                                             C. Filsfils
                                                                   Cisco
                                                            S. Litkowski
                                                                  Orange
                                                            May 14, 2019

  Signaling Entropy Label Capability and Entropy Readable Label Depth
                              Using IS-IS
                      draft-ietf-isis-mpls-elc-07

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 of processing 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 of
   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
   Task Force (IETF).  Note that other groups may also distribute
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   This Internet-Draft will expire on November 15, 2019.

Xu, et al.              Expires November 15, 2019               [Page 1]
Internet-Draft     Signaling ELC and ERLD using IS-IS           May 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
   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
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   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  Advertising ERLD Using IS-IS  . . . . . . . . . . . . . . . .   3
   4.  Advertising ELC Using IS-IS . . . . . . . . . . . . . . . . .   3
   5.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   4
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   4
   7.  Security Considerations . . . . . . . . . . . . . . . . . . .   4
   8.  Normative References  . . . . . . . . . . . . . . . . . . . .   4
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   6

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 scenario, 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 stacked 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 reading the maximum label stack depth and performing
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