Using BGP for routing in large-scale data centers
draft-lapukhov-bgp-routing-large-dc-03

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Replaced by RFC 7938, RFC 7938
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IDR                                                          P. Lapukhov
Internet-Draft                                           Microsoft Corp.
Intended status: Informational                                 A. Premji
Expires: August 14, 2013                                 Arista Networks
                                                       February 10, 2013

           Using BGP for routing in large-scale data centers
                 draft-lapukhov-bgp-routing-large-dc-03

Abstract

   Some service providers build and operate data centers that support
   over 100,000 servers.  In this document, such data centers are
   referred to as "large-scale" to differentiate them the from more
   common smaller infrastructures.  The environments of this scale have
   a unique set of network requirements, with emphasis on operational
   simplicity and network stability.

   This document summarizes ideas and experience of many people involved
   in designing and operating large scale data centers using BGP as the
   only control-plane protocol.  The intent here is to report a proven
   and stable routing design that could be leveraged by others in the
   industry.

Status of this Memo

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   This Internet-Draft will expire on August 14, 2013.

Copyright Notice

   Copyright (c) 2013 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

Lapukhov & Premji        Expires August 14, 2013                [Page 1]
Internet-Draft     draft-lapukhov-bgp-routing-large-dc     February 2013

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Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3
   2.  Document structure . . . . . . . . . . . . . . . . . . . . . .  3
   3.  Traditional data center designs  . . . . . . . . . . . . . . .  3
     3.1.  Layer 2 Designs  . . . . . . . . . . . . . . . . . . . . .  4
     3.2.  Fully routed network designs . . . . . . . . . . . . . . .  5
   4.  Network design requirements  . . . . . . . . . . . . . . . . .  5
     4.1.  Traffic patterns . . . . . . . . . . . . . . . . . . . . .  5
     4.2.  CAPEX minimization . . . . . . . . . . . . . . . . . . . .  6
     4.3.  OPEX minimization  . . . . . . . . . . . . . . . . . . . .  6
     4.4.  Traffic Engineering  . . . . . . . . . . . . . . . . . . .  7
   5.  Requirement List . . . . . . . . . . . . . . . . . . . . . . .  7
   6.  Network topology . . . . . . . . . . . . . . . . . . . . . . .  8
     6.1.  Clos topology overview . . . . . . . . . . . . . . . . . .  8
     6.2.  Clos topology properties . . . . . . . . . . . . . . . . .  9
     6.3.  Scaling Clos topology  . . . . . . . . . . . . . . . . . .  9
   7.  Routing design . . . . . . . . . . . . . . . . . . . . . . . . 10
     7.1.  Choosing the routing protocol  . . . . . . . . . . . . . . 10
     7.2.  BGP configuration for Clos topology  . . . . . . . . . . . 11
       7.2.1.  BGP Autonomous System numbering layout . . . . . . . . 11
       7.2.2.  Non-unique private BGP ASN's . . . . . . . . . . . . . 12
       7.2.3.  Prefix advertisement . . . . . . . . . . . . . . . . . 13
       7.2.4.  External connectivity  . . . . . . . . . . . . . . . . 13
       7.2.5.  Route aggregation at the network edge  . . . . . . . . 14
     7.3.  ECMP Considerations  . . . . . . . . . . . . . . . . . . . 15
       7.3.1.  Basic ECMP . . . . . . . . . . . . . . . . . . . . . . 15
       7.3.2.  BGP ECMP over multiple ASN . . . . . . . . . . . . . . 16
     7.4.  BGP convergence properties . . . . . . . . . . . . . . . . 16
       7.4.1.  Convergence timing . . . . . . . . . . . . . . . . . . 16
       7.4.2.  Failure impact scope . . . . . . . . . . . . . . . . . 17
     7.5.  Third-party route injection  . . . . . . . . . . . . . . . 18
   8.  Security Considerations  . . . . . . . . . . . . . . . . . . . 19
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