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GIRO : Geographically Informed Inter-domain Routing

GIRO : Geographically Informed Inter-domain Routing. Ricardo Oliveira, Mohit Lad, Beichuan Zhang, Lixia Zhang. AT&T. Sprint. 24.143.92/24. Verizon. Internet and Autonomous Systems. Autonomous System: a set of routers or networks under the same administration

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GIRO : Geographically Informed Inter-domain Routing

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  1. GIRO: Geographically Informed Inter-domain Routing Ricardo Oliveira, Mohit Lad, Beichuan Zhang, Lixia Zhang

  2. AT&T Sprint 24.143.92/24 Verizon Internet and Autonomous Systems • Autonomous System: a set of routers or networks under the same administration • Border routers exchange routing updates via the Border Gateway Protocol (BGP) • Reachability announced through the form of prefixes, i.e. chunks of IP addresses

  3. What problem we are solving • BGP route selection: how to pick the best one? ra ? rb Prefix P rc Policy: costumers > peers > providers Lowest AS hop count …

  4. P: AS 577 P: AS 3561, AS 577 One Example • Router A sends packets to prefix P • A has two ways to reach P: • Both AS 577 and AS 3561 are peer links • Following "lowest AS hop" rule: A sends packets to AS 577

  5. Suboptimal route selection ! Seattle, WA P AS577 AS3561 Chicago, IL AS6461 A Palo Alto, CA BGP path (~ 3600 miles) Shorter path (~700 miles)

  6. GIRO Design Goals 2. Improve routing scalability by reducing the global routing table size 1. Improve data delivery performance within established routing policies Geographical information

  7. GIRO Design Approach • Adding geographic information into • Routers • BGP routes • IP address • When everything else being equal: select path with shortest distance • Aggregate route announcements by ASes and locations

  8. Adding geographic information A xoutA, youtA • Configure each BGP router with geographic location informaiton • Define a new BGP "location" attribute to be associated with each AS hop e.g. using BGP communities • Enables each router to calculate the total path length xinB, yinB B xoutB, youtB xinC, yinC C xorigin, yorigin

  9. GIRO Address Scheme ASN geolocation SID Subnet and host Internal component External component (G-prefix) • Including ASN upfront in the address ensures that pkts are routedprimarily based on policies • Geolocation information serves as secondary hint • Traffic slice (SID) divides the incoming traffic to the G-prefix, e.g.one SID per provider • The internal component is not announced to other networks; it’s used to route pkts inside the origin network

  10. Prefix Aggregation in GIRO E D A SID=1 C SID=0 San Francisco,CA B New York,NY Toronto,CAN Los Angeles,CA Chicago,IL

  11. Egress Point Selection IGP weight Geographic distance R7 100|12 A 30|3 50|5 R4 R6 R5 200 0 0 R1 R2 R3 40|5 30|3 B shortest-path 90|10 early late late-exit R0

  12. GIRO Decision Process

  13. Evaluation: Inter-domain route selection • Used a RocketFuel PoP level topology with 668 inter-AS links and 67 ISPs • For simulations used =124 miles (equivalent of one sec. delay on fiber) • 70% of paths areshorter using GIRO compared to BGP • 20% of paths arereduced by more than 40%

  14. Evaluation: GIRO aggregation • Extracted prefixes from BGP tables from Jan 2007-March 2007 • Mapped each prefix to a geographical location using Maxmind Geolite • Found mapping for ~80% of prefixes (~196K)

  15. GIRO Aggregation • Geographical aggregation: aggregate all the prefixes that originated from the same origin AS and the same geolocation • Do not aggregate prefixes with different AS paths! • Preserve BGP AS path diversity

  16. Evaluation: GIRO Aggregation • GIRO achieves a 75% table size reduction compared to BGP

  17. Incremental deployment? • We do not have this: ASN geolocation SID Subnet and host • Would need IPv6 bits to fit it all in address field …

  18. A xoutA, youtA xinB, yinB B xoutB, youtB xinC, yinC C xorigin, yorigin But we can do this! • Configure each BGP router with geographic location informaiton • Define a new BGP "location" attribute to be associated with each AS hop (by usingcommunities) • Enables each router to calculate the total path length

  19. Conclusion and future work • Geolocation information can help improve path selection under routing policy constraints • Embedding ASN and geographical information in IP address can help improve routing scalability through aggregation • Exploring the possibility of utilizing geolocation in BGP routing, moving forward w/ an I-D very soon…

  20. Questions?rveloso@cs.ucla.edu

  21. Local cost Does shortest-path policy cost more locally? • Comparison between early-exit, late-exit, and shortest-path policy Global cost (geographical distance) • Shortest-path policy can reduce global cost significantly withoutsacrificing much of local cost

  22. AT&T Sprint 24.143.92/24 Verizon Internet and Autonomous Systems • Autonomous System: a set of routers or networks under the same administration • Border routers exchange routing updates via the Border Gateway Protocol (BGP) • Reachability announced through the form of prefixes, i.e. chunks of IP addresses

  23. Evaluation: GIRO Aggregation • GIRO achieves a 75% tablesize reduction compared to • BGP • About 40% of GIRO entries resulted from topological aggregation • 60% of entries resulted from geographical aggregation

  24. Inremental deployment? • Incremental deployability of GIRO: • Can embedd geographic info into BGP communities • What information to include in routes: absolute location or relative distance? • ISPs want to disclose minimal info about their networks • Geolocation info can help in doing fault diagnosis • GIRO can also help in: • Prefix hijacking: prefix ownership problem is solved; false link attacks can be mitigated • Source address spoofing, if border routers at origin net stamp (some) data pkts with their geolocation

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