BGP Topology Discovery Requirements
draft-ymbk-lsvr-discovery-req-01

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Last updated 2018-09-01
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Network Working Group                                            R. Bush
Internet-Draft                                              Arrcus & IIJ
Intended status: Informational                                  K. Patel
Expires: March 5, 2019                                            Arrcus
                                                       September 1, 2018

                  BGP Topology Discovery Requirements
                    draft-ymbk-lsvr-discovery-req-01

Abstract

   For wide scale routing protocols to build their topology and
   reachability databases they need link neighbor discovery, link
   encapsulation data, and layer two liveness.  BGP-LS and its
   enhancements provide an API to present much of these data to BGP
   protocols, but do not actually collect these data.  This document
   explores the needs and criteria for the data needed.

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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   Internet-Drafts are draft documents valid for a maximum of six months
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   This Internet-Draft will expire on March 5, 2019.

Copyright Notice

   Copyright (c) 2018 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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   include Simplified BSD License text as described in Section 4.e of

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   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Architectural Considerations  . . . . . . . . . . . . . . . .   2
   3.  Requirements  . . . . . . . . . . . . . . . . . . . . . . . .   3
   4.  Security Considerations . . . . . . . . . . . . . . . . . . .   4
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   4
   6.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .   5
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   5
     7.1.  Normative References  . . . . . . . . . . . . . . . . . .   5
     7.2.  Informative References  . . . . . . . . . . . . . . . . .   5
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   5

1.  Introduction

   In a massive scale datacenter or similar environment BGP([RFC4271])
   and BGP-like protocols, e.g.  BGP-SPF (see [I-D.ietf-lsvr-bgp-spf]),
   provide massive scale-out without centralization using a tried and
   tested scalable distributed control plane transport, offering a
   scalable routing solution.  But BGP4 and BGP-SPF need topology
   discovery, link state liveness, and link addressing data from the
   network to build and maintain the routing topology.

   BGP-LS [RFC7752] and its extensions provide an API which BGP4 and
   BGP-SPF can use to get the and distribute topology data.  But BGP-LS
   itself does not gather the data, it merely presents it.  So the
   topology data must be gathered.

   What topology data do BGP-like protocols actually need?  What level
   of freshness is needed?  What are the requirements for scale,
   extensibility, security, etc?

2.  Architectural Considerations

   Massive Data Centers (MDCs) have on the order of 10,000 racks, often
   with two Top Of Rack (TOR) devices per rack.  To provide this level
   of scaling reliably, stably, and securely imposes architectural
   constraints on any discovery protocol.

   o  Simple - If it isn't simple, it will not scale.  Simplicity
      requires restraint in design.  'Union Protocols' which are the sum
      of everyone's desires are complex disasters waiting to happen.
      Often they do not wait.  Prefer 'Intersection Protocols' which
      include only those things which everyone absolutely needs.

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   o  Securable - Security properties should be analysed.  Again,
      simplicity is key; complex protocols increase in complexity over
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