Carry congestion status in BGP community
draft-li-idr-congestion-status-extended-community-06

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Last updated 2017-10-27
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IDR                                                                Z. Li
Internet-Draft                                              China Mobile
Updates: 4271, 4360, 7153 (if approved)                          J. Dong
Intended status: Standards Track                     Huawei Technologies
Expires: April 29, 2018                                 October 26, 2017

                Carry congestion status in BGP community
          draft-li-idr-congestion-status-extended-community-06

Abstract

   To aid BGP receiver to steer the AS-outgoing traffic among the exit
   links, this document introduces a new BGP community, congestion
   status community, to carry the link bandwidth and utilization
   information, especially for the exit links of one AS.  If accepted,
   this document will update RFC4271, RFC4360 and RFC7153.

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 29, 2018.

Copyright Notice

   Copyright (c) 2017 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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   (https://trustee.ietf.org/license-info) in effect on the date of
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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.  Requirements Language . . . . . . . . . . . . . . . . . . . .   4
   3.  Previous Work . . . . . . . . . . . . . . . . . . . . . . . .   4
   4.  Solution Alternative 1: Extended Community  . . . . . . . . .   4
   5.  Solution Alternative 2: Large Community . . . . . . . . . . .   5
   6.  Solution Alternative 3: Community Container . . . . . . . . .   6
   7.  Deployment Considerations . . . . . . . . . . . . . . . . . .   7
   8.  Security Considerations . . . . . . . . . . . . . . . . . . .   8
   9.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   9
   10. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .   9
   11. References  . . . . . . . . . . . . . . . . . . . . . . . . .   9
     11.1.  Normative References . . . . . . . . . . . . . . . . . .   9
     11.2.  Informative References . . . . . . . . . . . . . . . . .  10
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  11

1.  Introduction

   Knowing the congestion status (bandwidth and utilization) of the AS
   exit links is useful for traffic steering, especially for steering
   the AS outgoing traffic among the exit links.  Section 7 of
   [I-D.gredler-idr-bgplu-epe] explicitly specifies this kind of
   requirement, which is also needed in our field network.

   The following figure is used to illustrate the benefits of knowing
   the congestion status of the AS exit links.  AS A has multiple exit
   links connected to AS B.  Both AS A and B has exit link to AS C, and
   AS B provides transit service for AS A.  Due to cost or some other
   reasons, AS A prefers using AS B to transmit its' traffic to AS C,
   not the directly connected link between AS A and C.  If the exit
   routers, Router 7 and 8, in AS A tell their iBGP peers the congestion
   status of the exit links, the peers in turn can steer some outgoing
   traffic toward the less loaded exit link.  If AS A knows the link
   between AS B and AS C is congested, it can steer some traffic towards
   AS C from AS B to the directly connected link by applying some route
   policies.

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