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Exchange Points, Route Servers and Registries

Exchange Points, Route Servers and Registries. Abha Ahuja ahuja@umich.edu. Objectives. To be able to explain what an exchange point is To be able to explain why people use XPs To understand why they are important To review some current exchange point designs used today

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Exchange Points, Route Servers and Registries

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  1. Exchange Points, Route Servers and Registries Abha Ahuja ahuja@umich.edu Exchange Points, Route Servers and Routing Registries

  2. Objectives • To be able to explain what an exchange point is • To be able to explain why people use XPs • To understand why they are important • To review some current exchange point designs used today • To think about how to set up an exchange point in your environment • To understand why Route Servers are useful • To be able to explain what routing registries do and why you should use one Exchange Points, Route Servers and Routing Registries

  3. Introduction to Exchange Points • a bit of history • What are they? • Why use them? Exchange Points, Route Servers and Routing Registries

  4. A Bit of History… • End of NSFnet - one major backbone • move towards commercial Internet • private companies selling their bandwidth • need for coordination of routing exchange between providers • Traffic from ISP A needs to get to ISP B • Routing Arbiter project created to facilitate this Exchange Points, Route Servers and Routing Registries

  5. What is an Exchange Point? • Network Access Points (NAPs) established at end of NSFnet • Major providers connect their networks and exchange traffic • High-speed network or switch • Simple concept - where providers come together to exchange traffic Exchange Points, Route Servers and Routing Registries

  6. Exchange points ISP A XP 1 XP 2 ISP B ISPs connect at Exchange Points or Network Access Points to exchange traffic Exchange Points, Route Servers and Routing Registries

  7. Conceptual Diagram of XP Exchange Point Medium Customer Router Customer Router Customer Router Exchange Points, Route Servers and Routing Registries

  8. Why use an Exchange Point? • Routers are attached to exchange traffic • MLPA, bilateral, customer/transit relationships • Examples in U.S: • AADS • Mae-East/Mae-West • Pacbell • PAIX Exchange Points, Route Servers and Routing Registries

  9. Internet B A Why XPs? • Multiple service providers • Each with Internet connectivity Exchange Points, Route Servers and Routing Registries

  10. Internet B A Why XPs? • Is not cost effective • Backhaul issue causes cost to both parties Exchange Points, Route Servers and Routing Registries

  11. Internet B A Why XPs? • Domestic Interconnection Exchange Points, Route Servers and Routing Registries

  12. Exchange Structures • layer 2 models (the NAP or IX) • tailored bilateral policies Exchange Points, Route Servers and Routing Registries

  13. Why use an Exchange Point? • Peering • Shared medium vs. point-to-point • Shared • can exchange traffic with multiple peers at one location via one interface • Point-to-Point • for high volumes of traffic Exchange Points, Route Servers and Routing Registries

  14. The Need for Exchanges AS 1 US ASIA AS 2 Exchange Points, Route Servers and Routing Registries

  15. The Need for Exchanges AS 1 US ASIA AS 2 Exchange Points, Route Servers and Routing Registries

  16. Why use an Exchange Point? • KEEP LOCAL TRAFFIC LOCAL!!! • ISPs within a region peer with each other at local exchange • No need to have traffic go overseas only to come back Exchange Points, Route Servers and Routing Registries

  17. Exchange Point Design • Ethernet • FDDI • ATM • Designs range from the simple to the complex • Fddi gigaswitches to ethernet switches Exchange Points, Route Servers and Routing Registries

  18. When can an XP be a bad thing? • Too many exchange points in one region • competing exchanges defeats the purpose • Becomes expensive for ISPs to connect to all of them Exchange Points, Route Servers and Routing Registries

  19. Exchange Point policies/politics • AUPs • Nobody is obliged to peer • don’t spoof Exchange Points, Route Servers and Routing Registries

  20. Exchange Point etiquette • Don’t point default • Third-party next-hop • Filter! Filter! Filter! • Or do reverse path check Exchange Points, Route Servers and Routing Registries

  21. Exchange Point examples • AADS (Ameritech) in Chicago, USA • ATM switches • Pacbell in California, USA • trunked (geographically diverse) ATM switches • PAIX in Palo Alto, California, USA • Fddi gigaswitches • MAE West in California, USA • trunked Fddi gigaswitches Exchange Points, Route Servers and Routing Registries

  22. Exchange Point examples • LINX in London, UK • Ethernet switches • AMS-IX in Amsterdam • Ethernet switches • NSPIXP-2 in Tokyo, Japan • Ethernet switches Exchange Points, Route Servers and Routing Registries

  23. Features of XPs • Redundancy • multiple switches • support • NOC to provide 24x7 support for problems at the exchange • DNS, Routing Registries, NTP servers • servers often colocated at these centralized points Exchange Points, Route Servers and Routing Registries

  24. Features of XPs • location • neutral colocation facilities • address space • AS • Route servers • statistics Exchange Points, Route Servers and Routing Registries

  25. More info about IXs • http://www.ep.net • http://www.rsng.net Exchange Points, Route Servers and Routing Registries

  26. Things to think about... • Do you need to be at an Exchange Point? • Would you want to start an Exchange Point? • Would keeping local traffic local benefit your ISP? • Would your environment (politically, etc.) support an Exchange Point? Exchange Points, Route Servers and Routing Registries

  27. Discussion • How would you build an exchange point in your environment? • Who would connect? • What services would you provide? • What policies would you enforce? • What does your environment look like? • Is it feasible to set up an XP? Exchange Points, Route Servers and Routing Registries

  28. Route Server Background • What is a Route Server? • Features of a Route Server • Advantages of using a Route Server • Exchange Point Design with a Route Server Exchange Points, Route Servers and Routing Registries

  29. What is a Route Server? • Unix box which runs Route Server software • Exchanges routing information with service provider routers at a NAP based on policy • Does not forward packets Exchange Points, Route Servers and Routing Registries

  30. Route Server at an XP R1 NAP R2 R3 ROUTE SERVER Exchange Points, Route Servers and Routing Registries

  31. Features of a Route Server • Scalable Routing • Simplified Routing Processes on ISP Routers • Insertion of RS Autonomous System Number in the Routing Path Exchange Points, Route Servers and Routing Registries

  32. Features of a Route Server (con) • Handling of Multi-Exit Discriminator • Route Flap Dampening Mechanism • Uses Policy registered in IRR Exchange Points, Route Servers and Routing Registries

  33. Diagram of N-squared Mesh Exchange Points, Route Servers and Routing Registries

  34. With the Route Servers Exchange Points, Route Servers and Routing Registries

  35. RS Exchange Point Routing Flow TRAFFIC FLOW ROUTING INFORMATION FLOW Exchange Points, Route Servers and Routing Registries

  36. Advantages of Using a Route Server • Scalable Routing • Separation of Routing and Forwarding • Simplify Routing Configuration Management on ISPs routers • Enforce Good Routing Engineering Exchange Points, Route Servers and Routing Registries

  37. Advantages of Using a Route Server (con) • PREVENTS SPREAD OF BOGUS ROUTING INFORMATION! Exchange Points, Route Servers and Routing Registries

  38. Peering with the Route Servers • Any ISP attached to a NAP can peer with the Route Servers • ISP must register their policy in the Internet Routing Registry • Must use BGP Exchange Points, Route Servers and Routing Registries

  39. Route Server Daemon Originally developed by ISI during RA project Developed from GateD Multi-view eBGP only Uses import-from only RSd Exchange Points, Route Servers and Routing Registries

  40. Things to think about... • How would using a route server benefit you? • Consider setting one up yourself for your community, or talk to Merit... Exchange Points, Route Servers and Routing Registries

  41. Route Server References • http://www.rsng.net • http://www.merit.edu/ipma • http://www.isi.edu/ra Exchange Points, Route Servers and Routing Registries

  42. What is the Routing Registry? • contact names, email addresses and telephone numbers for an AS • routing policy for an AS (what other ASes does it connect to, which routes do they exchange) • information about routes (most important is which AS originates the route) • several other types of information Exchange Points, Route Servers and Routing Registries

  43. What is the Routing Registry? • Distributed database collectively known as Internet Routing Registry (IRR) • RADB, RIPE, CW, ANS, Canet • Providers register routing policy • Used for planning, debugging and generating backbone router configs • http://www.radb.net/ Exchange Points, Route Servers and Routing Registries

  44. What is the Routing Registry? • Can be used by anyone worldwide • debugging • configuring • engineering routing • addressing Exchange Points, Route Servers and Routing Registries

  45. What happens if I don’t use a database? • Routing Horror Stories • AS7007 • announcing bogus routes Exchange Points, Route Servers and Routing Registries

  46. So, I need to use the database because….. • Filters generated off the IRR protect against inaccurate routing information • Makes troubleshooting and debugging easier • Keep track of policy • Security • Filter! Filter! Filter!! Exchange Points, Route Servers and Routing Registries

  47. Why Bother with all of this? • View of global routing policy in a single cooperatively maintained database • to improve integrity of Internet’s routing • generate router configs • protect against inaccurate routing info distribution • verification of Internet routing Exchange Points, Route Servers and Routing Registries

  48. Why Bother using the database (con) • Many providers require that you register your policy (or they won’t peer with you) Exchange Points, Route Servers and Routing Registries

  49. Policy Languages • express policy with aut-num objects, route objects, AS-MACROS • currently RIPE-181 • moving to RPSL • more policy control Exchange Points, Route Servers and Routing Registries

  50. What is RPSL? • Routing Policy Specification Language • Designed to replace current language (RIPE-181) • Enhanced and more generalized Exchange Points, Route Servers and Routing Registries

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