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NANOG Meeting Presentation Abstract

Redistribution Communities for Interdomain Traffic Engineering
Meeting: NANOG25
Date / Time: 2002-06-10 3:30pm - 4:00pm
Room: Grand York Ballroom
Presenters: Speakers:
Bruno Quoitin, University of Namur, Belgium.
Olivier Bonaventure, University of Namur, Belgium.
Abstract: Since its introduction several years ago, the BGP community attribute [TCL96, CB96] has been used for several purposes. In this presentation, we describe a detailed study of today\'s utilization of the BGP community attribute [QB02a].



In the first part of the presentation we show that ISPs use the Community attribute for new purposes in the global Internet. We distinguish the two most common utilizations of the Community attribute: route tagging and traffic engineering.

  • Route tagging consists, for an ISP, in attaching Community values to a route received from an external peer in order to indicate the location that issued the route. Various types of locations are used in practice: geographic, interconnection point, and AS number, as well as the type of peer (customer/peering partner/transit provider).



  • Traffic engineering consists in attaching Community values to a route in order to influence its redistribution by downstream routers. Three types of Community values are used today to influence the redistribution towards specific peers or interconnection points: do not announce the route, prepend to the AS path or change the local preference.




In the second part of the talk we focus on the frequency of utilization of these two types of communities by presenting the results of a detailed analysis [QB02b] of the BGP table dumps from the RIPE RIS and RouteViews projects [RIS02, Mey02]. A first observation shows that Communities are widely used in the global Internet. For instance, nearly 50% of the routes advertised to the test router maintained by RIPE had at least one community attached. We have also classified communities that appear in the global Internet on the basis of the RIPE whois database [RIW02]. Based on this classification, we show that the Communities used for route tagging or traffic engineering represent a large part of the Communities present in the global Internet.
Based on this analysis, it appears that the Community attribute is widely used. However, a drawback of this attribute is that each ISP needs to define and document its own Community values. This is flexible but requires a lot of error-prone manual configurations that are difficult to maintain. Furthermore, the limited size of the Community space has caused some ISPs to use Community values in their private AS or reserved space.



To cope with these limitations of the Community attribute, we describe an new type of extended community attribute [RTR01] called the redistribution communities [BCH^+02] that are currently being developed within IETF and can be used to support many of the current utilizations of the Community attribute in a more flexible manner. Furthermore, we show that the cost of supporting this new type of extended communities in a BGP router is minor based on our experience in implementing on the zebra platform [Quo02].



Acknowledgments



This work was partially funded by the European Commission within the IST ATRIUM project.



This work would not have been possible without the very useful information provided by the RIPE RIS project, the RIPE WHOIS database and the RouteViews project.



Referencess



[BCH^+02] O. Bonaventure, S. De Cnodder, J. Haas, B. Quoitin, and R. White. Controlling the redistribution of bgp routes. Internet draft, draft-ietf-ptomaine-bgp-redistribution-00.txt, work in progress, April 2002.
[CB96] E. Chen and T. Bates. An Application of the BGP Community Attribute in Multi-home Routing. Internet Engineering Task Force, RFC1998, August 1996.



[Mey02] D. Meyer. Route Views Archive project. University of Oregon, http://archive.routeviews.org, January 2002.



[QB02a] B. Quoitin and O. Bonaventure. A survey of the utilization of bgp communities. Internet draft, draft-quoitin-bgp-comm-survey-00.txt, work in progress, February 2002. http://www.infonet.fundp.ac.be /doc/reports/Infonet-TR-2002-02.pdf.



[QB02b] B. Quoitin and O. Bonaventure. Utilization of the BGP Communities attribute. http://alpha.infonet.fundp.ac.be/anabgp, January 2002. Infonet Group, University of Namur, Belgium.



[Quo02] B. Quoitin. An implementation of the BGP Redistribution Communities in Zebra. http://www.infonet.fundp.ac.be/doc/tr/Infonet-TR-2002-0 3.html, February 2002. Technical Report TR-2002-3, Infonet Group, University of Namur, Belgium.



[RIS02] Routing Information Service project. Réseaux IP Européens, http://www.ripe.net/ripencc/pub-services/np/ris-index.h tml, January 2002.



[RIW02] Whois database. RIPE NCC, http://abcoude.ripe.net/ris/rawdata, January 2002.



[RTR01] S. Ramachandra, D. Tappan, and Y. Rekhter. BGP Extended Communities Attribute. Internet draft, draft-ramachandra-bgp-ext-communities-09.txt, Work In Progress, June 2001.



[TCL96] P. Traina, R. Chandrasekeran, and T. Li. BGP Communities Attribute. Internet Engineering Task Force, RFC1997, August 1996.
Files: pdfBruno Quoitin Presentation(PDF)
youtubeRedistribution Communities for Interdomain Traffic Engineering
Sponsors: None.

Back to NANOG25 agenda.

NANOG25 Abstracts

  • Panel: Smart Routing Technologies
    Moderators:
    Sue HaresNextHop; .
    Panelists:
    Jeremy JohnsonnetVmg; .
    Aaron BrittOpnix; .
    Robert BaysProficient; .
    Mike LloydRouteScience; .
    Daniel GoldingSockeye; .
    Brandon RossSockeye; .
  • Panel: Smart Routing Technologies
    Moderators:
    Sue HaresNextHop; .
    Panelists:
    Jeremy JohnsonnetVmg; .
    Aaron BrittOpnix; .
    Robert BaysProficient; .
    Mike LloydRouteScience; .
    Daniel GoldingSockeye; .
    Brandon RossSockeye; .
  • Panel: Smart Routing Technologies
    Moderators:
    Sue HaresNextHop; .
    Panelists:
    Jeremy JohnsonnetVmg; .
    Aaron BrittOpnix; .
    Robert BaysProficient; .
    Mike LloydRouteScience; .
    Daniel GoldingSockeye; .
    Brandon RossSockeye; .
  • Panel: Smart Routing Technologies
    Moderators:
    Sue HaresNextHop; .
    Panelists:
    Jeremy JohnsonnetVmg; .
    Aaron BrittOpnix; .
    Robert BaysProficient; .
    Mike LloydRouteScience; .
    Daniel GoldingSockeye; .
    Brandon RossSockeye; .
  • Panel: Smart Routing Technologies
    Moderators:
    Sue HaresNextHop; .
    Panelists:
    Jeremy JohnsonnetVmg; .
    Aaron BrittOpnix; .
    Robert BaysProficient; .
    Mike LloydRouteScience; .
    Daniel GoldingSockeye; .
    Brandon RossSockeye; .
  • Panel: Smart Routing Technologies
    Moderators:
    Sue HaresNextHop; .
    Panelists:
    Jeremy JohnsonnetVmg; .
    Aaron BrittOpnix; .
    Robert BaysProficient; .
    Mike LloydRouteScience; .
    Daniel GoldingSockeye; .
    Brandon RossSockeye; .
  • Panel: Smart Routing Technologies
    Moderators:
    Sue HaresNextHop; .
    Panelists:
    Jeremy JohnsonnetVmg; .
    Aaron BrittOpnix; .
    Robert BaysProficient; .
    Mike LloydRouteScience; .
    Daniel GoldingSockeye; .
    Brandon RossSockeye; .

 

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