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Internet Exchange Points

Internet Exchange Points. Brian Longwe brian@pure-id.com. Objectives. To be able to explain what Internet Exchange Point (IXP) is To be able to explain why people use IXPs To understand why IXPs are important To review some current IXP designs used today

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Internet Exchange Points

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  1. Internet Exchange Points Brian Longwe brian@pure-id.com AfNOG 2004, Dakar, Senegal

  2. Objectives • To be able to explain what Internet Exchange Point (IXP) is • To be able to explain why people use IXPs • To understand why IXPs are important • To review some current IXP designs used today • To think about how to set up an exchange point in your environment • To understand why Route Reflectors are useful AfNOG 2004, Dakar, Senegal

  3. Introduction to Exchange Points • A bit of history • What are they? • Why use them? AfNOG 2004, Dakar, Senegal

  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 AfNOG 2004, Dakar, Senegal

  5. What is an Exchange Point? • Internet Exchange Point • Interconnection points of the Internet. • Places where ISPs come to interconnect with each other. • “Clearing House” for Internet traffic • IXPs “Keep local traffic local” “IXPs are the keystone of the entire Internet economy.” Cisco Systems AfNOG 2004, Dakar, Senegal

  6. What is an Exchange Point? • Major providers connect their networks and exchange traffic • High-speed network or switch • Simple concept - anyplace where providers come together to exchange traffic AfNOG 2004, Dakar, Senegal

  7. Exchange points Gateways ISP A ISP C ISP B IXP ISPs connect at Internet Exchange Points to exchange traffic AfNOG 2004, Dakar, Senegal

  8. Conceptual Diagram of XP Exchange Point Medium Customer Router Customer Router Customer Router AfNOG 2004, Dakar, Senegal

  9. Why use an Exchange Point? • Routers are attached to exchange traffic • MLPA, bilateral, customer/transit relationships • Examples in Africa: • JINX - Johannesburg, South Africa • KIXP - Nairobi, Kenya • MOZIX - Maputo, Mozambique • UIXP - Kampala, Uganda • TIXP - Dar es Salaam, Tanzania AfNOG 2004, Dakar, Senegal

  10. Internet B A Why XPs? • Multiple service providers • Each with Internet connectivity AfNOG 2004, Dakar, Senegal

  11. Internet B A Why XPs? • Is not cost effective • Backhaul issue causes cost to both parties AfNOG 2004, Dakar, Senegal

  12. Internet B A Why XPs? • Domestic Interconnection AfNOG 2004, Dakar, Senegal

  13. Exchange Structures • layer 2 models (the NAP or IX) • tailored bilateral policies AfNOG 2004, Dakar, Senegal

  14. Exchange Structures • Private Interconnects at IXP AfNOG 2004, Dakar, Senegal

  15. 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 AfNOG 2004, Dakar, Senegal

  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 USA 200-900ms 200-900ms ISP A ISP B 5-20ms AfNOG 2004, Dakar, Senegal

  17. Metcalfe’s Law The magic of Interconnections “The usefulness, or utility, of a network equals the square of the number of users.” Robert Metcalfe Connect any number, "n" of machines – whether computers, phones or even cars - and you get “n” squared potential value. n21 + n22 + n23 + n24 + n25 …………. n2n AfNOG 2004, Dakar, Senegal

  18. More ISPs, More Value! ISP #2 ISP #1 ISP #2 ISP #3 ISP #4 The more ISPs interconnect, the more value each individual ISP can offer it’s customers! ISP #5 ISP #n AfNOG 2004, Dakar, Senegal

  19. The Law of Disruption “Social, political, and economic systems change incrementally but technology changes exponentially” Downes & Mui Once there is a critical mass of users, the rate-of-change (disruption index) accelerates exponentially. It is in the growing chasm between the different rates of change that a second-order effect occurs AfNOG 2004, Dakar, Senegal

  20. AfNOG 2004, Dakar, Senegal

  21. Growing Domestic bandwidth independently of International Bandwidth AfNOG 2004, Dakar, Senegal

  22. Exchange Point Design • Ethernet • FDDI • ATM • Designs range from the simple to the complex • Layer 2 (Ethernet Switch-based) • Layer 3 (Router-based) - discouraged • Layer 2 with Route Reflector AfNOG 2004, Dakar, Senegal

  23. When can an IXP 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 AfNOG 2004, Dakar, Senegal

  24. Exchange Point policies/politics • AUPs • acceptable use policy • rules for connection • Fees? • Nobody is obliged to peer • Don’t spoof AfNOG 2004, Dakar, Senegal

  25. Exchange Point etiquette • Don’t point default • Third-party next-hop • Filter! Filter! Filter! • Or do reverse path check AfNOG 2004, Dakar, Senegal

  26. Exchange Point examples • MOZIX in Maputo, Mozambique • Ethernet switches in University • TIXP in Dar es Salaam, Tanzania • Ethernet Switches on rooftop of Posta Bldg • KIXP in Nairobi, Kenya • Ethernet switches in ISP Association offices • JINX in Johannesburg, South Africa • Ethernet switches in colocation facility provided free by member • UIXP in Kampala, Uganda • Ethernet switches in basement of regulator’s building - rent free “forever-and-ever Amen” AfNOG 2004, Dakar, Senegal

  27. Features of XPs • Redundancy • multiple switches • support • NOC to provide 24x7 support for problems at the exchange - generally ISPs help out with this • DNS, Routing Registries, NTP servers • servers often colocated at these centralized points • CCTLD mirror • Major Content Distribution systems: Akamai etc… AfNOG 2004, Dakar, Senegal

  28. Features of XPs • location • neutral colocation facilities • address space • Autnomous System Numg • Route servers • statistics AfNOG 2004, Dakar, Senegal

  29. More info about IXs • http://www.afrispa.org • Will maintain database on African IXPs and tools/resources for establishing IXPs • http://www.afrinic.org • African IP Address Registry - will facilitate blocks of IP address space and ASNs for IXPs • http://www.ep.net • route server and statistics resource AfNOG 2004, Dakar, Senegal

  30. 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? AfNOG 2004, Dakar, Senegal

  31. 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? AfNOG 2004, Dakar, Senegal

  32. Important to Remember... • Exchange Points can be as simple as a HUB!!!! • Keeping local traffic local • improves performance • cheaper • often simple to do! AfNOG 2004, Dakar, Senegal

  33. Exercise - The Benefits of Exchange Points AfNOG 2004, Dakar, Senegal

  34. AS 1100 AS 3100 AS 5100 AS 7100 AS 9100 AS 2100 AS 4100 AS 6100 AS 8100 AS 10100 BGP to provider AS 1 AS 2 AfNOG 2004, Dakar, Senegal

  35. AS 100 AS 100 AS 100 AS 100 AS 100 AS 100 AS 100 AS 100 AS 100 AS 100 84.201.60.0/24 Ethernet to IXP SWITCH AfNOG 2004, Dakar, Senegal

  36. 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 AfNOG 2004, Dakar, Senegal

  37. What is a Route Server? • Unix box which runs Route Server software • Router which activates Route Reflector BGP feature • Exchanges routing information with service provider routers at an IX based on policy • Does not forward packets - only handles routing logic AfNOG 2004, Dakar, Senegal

  38. Route Reflector at an XP R1 Switching Fabric R2 R3 ROUTE SERVER AfNOG 2004, Dakar, Senegal

  39. Route Reflector at an XP AfNOG 2004, Dakar, Senegal

  40. Features of a Route Server • Route reflectors are sometimes confused with route servers (and vice versa). • Route servers are generally used at Internet exchange points. • The objective is for routers to only peer with the route server (not all the other routers in the exchange) and obtain all the routing information from it. • The route server has the capability of propagating information in a transparent fashion—as if the advertisements were received directly from the router originating it. AfNOG 2004, Dakar, Senegal

  41. Route Server at the IXP AfNOG 2004, Dakar, Senegal

  42. Route Server at the IXP AfNOG 2004, Dakar, Senegal

  43. Diagram of N-squared Mesh AfNOG 2004, Dakar, Senegal

  44. With the Route Reflectors AfNOG 2004, Dakar, Senegal

  45. RR Exchange Point Routing Flow TRAFFIC FLOW ROUTING INFORMATION FLOW AfNOG 2004, Dakar, Senegal

  46. Advantages of Using a Route Server • Scalable Routing • Separation of Routing and Forwarding • Simplify Routing Configuration Management on ISPs routers • Enforce Good Routing Engineering AfNOG 2004, Dakar, Senegal

  47. Advantages of Using a Route Server (con) • PREVENTS SPREAD OF BOGUS ROUTING INFORMATION! AfNOG 2004, Dakar, Senegal

  48. Exercise - Route Server at Internet Exchange Point AfNOG 2004, Dakar, Senegal

  49. AS 100 AS 100 AS 100 AS 100 AS 100 AS 100 AS 100 AS 100 AS 100 AS 100 Route Server 84.201.60.0/24 Ethernet to IXP SWITCH AfNOG 2004, Dakar, Senegal

  50. AS 1100 AS 65523 AS 5100 AS 65523 AS 2100 AS 65523 AS 6100 AS 65523 AS 65523 AS 10100 Route Server 65523 84.201.60.0/24 AS 1 AS 2 IXP SWITCH AfNOG 2004, Dakar, Senegal

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