Advertising L2 Bundle Member Link Attributes in OSPF
draft-ketant-lsr-ospf-l2bundles-02

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Link State Routing                                         K. Talaulikar
Internet-Draft                                                 P. Psenak
Intended status: Standards Track                           Cisco Systems
Expires: January 1, 2021                                   June 30, 2020

          Advertising L2 Bundle Member Link Attributes in OSPF
                   draft-ketant-lsr-ospf-l2bundles-02

Abstract

   There are deployments where the Layer 3 interface on which OSPF
   operates is a Layer 2 interface bundle.  Existing OSPF advertisements
   only support advertising link attributes of the Layer 3 interface.
   If entities external to OSPF wish to control traffic flows on the
   individual physical links which comprise the Layer 2 interface bundle
   link attribute information about the bundle members is required.

   This document introduces the ability for OSPF to advertise the link
   attributes of layer 2 (L2) Bundle members.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
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   This Internet-Draft will expire on January 1, 2021.

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   to this document.  Code Components extracted from this document must
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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Requirements Language . . . . . . . . . . . . . . . . . .   3
   2.  L2 Bundle Member Attributes . . . . . . . . . . . . . . . . .   3
   3.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   6
   4.  Security Considerations . . . . . . . . . . . . . . . . . . .   7
   5.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   7
   6.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   7
     6.1.  Normative References  . . . . . . . . . . . . . . . . . .   7
     6.2.  Informational References  . . . . . . . . . . . . . . . .   8
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   9

1.  Introduction

   There are deployments where the Layer 3 interface on which an OSPF
   adjacency is established is a Layer 2 interface bundle, for instance
   a Link Aggregation Group (LAG) [IEEE802.1AX] . This reduces the
   number of adjacencies which need to be maintained by the routing
   protocol in cases where there are parallel links between the
   neighbors.  Entities external to OSPF such as Path Computation
   Elements (PCE) [RFC4655] may wish to control traffic flows on
   individual members of the underlying Layer 2 bundle.  In order to do
   so link attribute information about individual bundle members is
   required.  The protocol extensions defined in this document provide
   the means to advertise this information.

   This document introduces new sub-TLVs to advertise link attribute
   information for each of the L2 Bundle members which comprise the
   Layer 3 interface on which OSPF operates.  Similar capabilities were
   introduced in IS-IS via [RFC8668].

   [RFC8665] and [RFC8666] introduced the adjacency segment identifier
   (Adj-SID) link attribute for OSPFv2 and OSPFv3 respectively which can
   be used as an instruction to forwarding to send traffic over a
   specific link [RFC8402].  This document enables the advertisement of
   the Adj-SIDs using the same Adjacency SID sub-TLV at the granularity
   level of each L2 Bundle member link so that traffic may be steered
   over that specific member link.

   Note that the new advertisements at the L2 Bundle member link level
   in this document are intended to be provided to external (to OSPF)
   entities and does not alter or change OSPF route computation process.

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