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NANOG Meeting Presentation Abstract

Benefits of Negotiated Interdomain Traffic Engineering
Meeting: NANOG31
Date / Time: 2004-05-24 11:00am - 11:30am
Room: Grand Ballroom
Presenters: Speakers:

Ratul Mahajan, University of Washington

Ratul Mahajan received a B.Tech. degree from the Indian Institute of Technology, Delhi, India, and an M.S. degree from the University of Washington. He is currently pursuing a Ph.D. degree at the University of Washington. His research interests span the entire range of internetworking-related topics. His past work includes a study of global routing configuration errors and discovering Internet topology and routing policies.
David Wetherall, University of Washington.
Thomas Anderson, University of Washington.
Abstract: Current interdomain routing policies are based on information local to each ISP and optimized for the benefit of that ISP. It is known that this combination can to lead to sub-optimal Internet paths and even unpredictable results. Paths can be sub-optimal because decisions that appear locally sound may have adverse global effects, such as when early-exit routing sends packets further from the ultimate destination. Behavior can be unpredictable because the actions of one ISP can have an unintended influence on the other and vice versa, and in the worst case cycles of influence can lead to oscillations as traffic is re-routed. Today, these problems are resolved by operator intervention, not by protocols.

We present work that examines whether two neighboring ISPs can benefit by using automated negotiation to determine the paths of traffic that they exchange. There is an incentive to negotiate only if both ISPs benefit relative to making independent decisions. To see if this is so, we simulated ISP routing choices driven by latency reduction and hotspot avoidance over sixty measured ISP topologies with a variety of traffic models. We find negotiation most valuable as a means of avoiding hotspots. It also provides a modest decrease in latencies, which suggests that the \"price of anarchy\" is low in terms of path length with real ISP topologies, even though it can be substantial in the theoretical worst case. Interestingly, we also find that global optimization (which treats both ISPs as a single larger ISP) is undesirable in the sense that in some cases one ISP can suffer to benefit the other.

We also describe our first steps towards a practical negotiation protocol. ISPs can already influence each other\'s routing decisions to some extent (e.g., via MEDs and AS-path prepending), but this influence is mostly indirect, coarse, often governed by trial-and-error and supplemented by out-of-band agreements between operators. Our intent is to help operators by relieving them of the bulk of the tedious and error-prone task of responding to traffic engineering problems, such as an overloaded peering link, while allowing them to maintain control over the result. It accommodates competitive concerns by revealing little ISP-internal information and independent ISP management by allowing different optimization criteria. We find that it selects routing strategies that realize most of the potential benefits identified in our study. We are particularly interested in operator feedback on the need for, requirements, and utility of this kind of mechanism.
Files: youtubeBenefits of Negotiated Interdomain Traffic Engineering
pdfRatul Mahajan - Traffic Engineering(PDF)
Sponsors: None.

Back to NANOG31 agenda.

NANOG31 Abstracts

  • Happy Packets - Initial Results
    Speakers:
    Randy Bush, IIJ; Tim GriffinIntel Research; .
    Zhuoqing MaoUniversity of Michigan; .
    Eric PurpusUniversity of Oregon; .
    Dan StutzbachUniversity of Oregon; .
  • Happy Packets - Initial Results
    Speakers:
    Randy Bush, IIJ; Tim GriffinIntel Research; .
    Zhuoqing MaoUniversity of Michigan; .
    Eric PurpusUniversity of Oregon; .
    Dan StutzbachUniversity of Oregon; .
  • Happy Packets - Initial Results
    Speakers:
    Randy Bush, IIJ; Tim GriffinIntel Research; .
    Zhuoqing MaoUniversity of Michigan; .
    Eric PurpusUniversity of Oregon; .
    Dan StutzbachUniversity of Oregon; .
  • Happy Packets - Initial Results
    Speakers:
    Randy Bush, IIJ; Tim GriffinIntel Research; .
    Zhuoqing MaoUniversity of Michigan; .
    Eric PurpusUniversity of Oregon; .
    Dan StutzbachUniversity of Oregon; .
  • Happy Packets - Initial Results
    Speakers:
    Randy Bush, IIJ; Tim GriffinIntel Research; .
    Zhuoqing MaoUniversity of Michigan; .
    Eric PurpusUniversity of Oregon; .
    Dan StutzbachUniversity of Oregon; .

 

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