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AGORA: A Market for Internet Connectivity

AGORA: A Market for Internet Connectivity. Nick Feamster, Georgia Tech Ramesh Johari, Stanford Vijay Vazirani, Georgia Tech. Today’s Internet: Bilateral Contracts. End-to-end connectivity largely determined by bilateral contracts between pairs of ASes Two types of inefficiency

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AGORA: A Market for Internet Connectivity

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  1. AGORA: A Market for Internet Connectivity Nick Feamster, Georgia TechRamesh Johari, StanfordVijay Vazirani, Georgia Tech

  2. Today’s Internet: Bilateral Contracts • End-to-end connectivity largely determined by bilateral contracts between pairs of ASes • Two types of inefficiency • Market inefficiency: Excess capacity, unfulfilled demand • Connectivity inefficiency: longer-than-necessary paths $$ Abilene Comcast $$ $$ $$ AT&T $$ Cogent

  3. Market Inefficiency • Pair of ASes may decide to terminate connectivity arrangement • Even if end nodes would pay for the path to be there! October 2005 April 2007 31 Jul 2005: Level 3 Notifies Cogent of intent to disconnect. 16 Aug 2005: Cogent begins massive sales effort and mentions a 15 Sept. expected depeering date. 31 Aug 2005: Level 3 Notifies Cogent again of intent to disconnect (according to Level 3) 5 Oct 2005 9:50 UTC: Level 3 disconnects Cogent. Mass hysteria ensues up to, and including policymakers in Washington, D.C. 7 Oct 2005: Level 3 reconnects Cogent During the “outage”, Level 3 and Cogent’s singly homed customers could not reach each other. (~ 4% of the Internet’s prefixes were isolated from each other)

  4. Connectivity Inefficiency • Paths become longer simply because two ASes decide not to interconnect $$ Abilene Comcast $$ $$ $$ AT&T $$ Cogent Peering pointsin Atlanta Peering pointin Washington, D.C.

  5. AGORA: AGregator-Oriented Architecture Two Proposed Changes • End-to-end paths flow through aggregators • Long-haul providers offer connectivity between aggregators • Connectivity between aggregators is black-box • May be connectivity on single path, or along multiple paths • Structure of Internet paths • Exploit new structure to allow new types of contracts Aggregators as waypoints(“layer 3 exchanges”) Market makers as clearinghouses M

  6. Protocol Operation • Provider advertises, per ingress/egress pair • available capacity and • a price for that capacity • Market maker(s) compile the pairs of endpoints to be bought and sold • Stub networks request end-to-end connectivity from market makers • Market makers solve an optimization problem and allocate resources to stub networks

  7. Contracts: Three Types • Best effort connectivity • Long-term contracts • Established ahead of time, for set of destinations that stub network is really concerned with reaching • Short-term contracts • Recovery from rare, catastrophic periods of disconnection

  8. Challenges • Protocol for resource advertisement • PCE/Interdomain connectivity database (?) • Algorithm for resource allocation and computation of end-to-end paths • Protocol to handle transactions for resources • Possible race conditions • Scaling considerations • Incentives for long-haul providers to invest

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