AGORA: A Market for Internet Connectivity
-
Upload
malachi-hubbard -
Category
Documents
-
view
30 -
download
1
description
Transcript of AGORA: A Market for Internet Connectivity
![Page 1: AGORA: A Market for Internet Connectivity](https://reader035.fdocuments.in/reader035/viewer/2022072017/56813479550346895d9b5a2a/html5/thumbnails/1.jpg)
AGORA: A Market for Internet Connectivity
Nick Feamster, Georgia TechRamesh Johari, Stanford
Vijay Vazirani, Georgia Tech
![Page 2: AGORA: A Market for Internet Connectivity](https://reader035.fdocuments.in/reader035/viewer/2022072017/56813479550346895d9b5a2a/html5/thumbnails/2.jpg)
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
Comcast
Abilene
AT&T Cogent
$$
$$
$$$$
$$
![Page 3: AGORA: A Market for Internet Connectivity](https://reader035.fdocuments.in/reader035/viewer/2022072017/56813479550346895d9b5a2a/html5/thumbnails/3.jpg)
3
Market Inefficiency• Pair of ASes may decide to terminate connectivity arrangement
– Even if end nodes would pay for the path to be there!
31 Jul 2005: Level 3 Notifies Cogent of intent to disconnect.16 Aug 2005: Cogent begins massive sales effort andmentions a 15 Sept. expected depeering date.31 Aug 2005: Level 3 Notifies Cogent again of intent todisconnect (according to Level 3)5 Oct 2005 9:50 UTC: Level 3 disconnects Cogent. Masshysteria ensues up to, and including policymakers inWashington, 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)
October 2005 April 2007
![Page 4: AGORA: A Market for Internet Connectivity](https://reader035.fdocuments.in/reader035/viewer/2022072017/56813479550346895d9b5a2a/html5/thumbnails/4.jpg)
4
Connectivity Inefficiency
• Paths become longer simply because two ASes decide not to interconnect
Comcast
Abilene
AT&T Cogent
$$
$$
$$$$
$$
Peering pointsin Atlanta
Peering pointin Washington, D.C.
![Page 5: AGORA: A Market for Internet Connectivity](https://reader035.fdocuments.in/reader035/viewer/2022072017/56813479550346895d9b5a2a/html5/thumbnails/5.jpg)
5
AGORA: AGregator-Oriented Architecture
• 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
Two Proposed Changes
Aggregators as waypoints(“layer 3 exchanges”)
Market makers as clearinghouses
M
![Page 6: AGORA: A Market for Internet Connectivity](https://reader035.fdocuments.in/reader035/viewer/2022072017/56813479550346895d9b5a2a/html5/thumbnails/6.jpg)
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
![Page 7: AGORA: A Market for Internet Connectivity](https://reader035.fdocuments.in/reader035/viewer/2022072017/56813479550346895d9b5a2a/html5/thumbnails/7.jpg)
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
![Page 8: AGORA: A Market for Internet Connectivity](https://reader035.fdocuments.in/reader035/viewer/2022072017/56813479550346895d9b5a2a/html5/thumbnails/8.jpg)
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