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IP Switching for Scalable IP Services Hassan M. Ahmed Ross Callon Andrew G. Malis Hohn Moy

IP Switching for Scalable IP Services Hassan M. Ahmed Ross Callon Andrew G. Malis Hohn Moy. Presented by Gao, Yun Shih, Pei-Shin Wei, ShuGuang. OUTLINE. Background Review & Motivation The Overlay Model: Classical IP over ATM IP Switching IP Navigator Conclusion.

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IP Switching for Scalable IP Services Hassan M. Ahmed Ross Callon Andrew G. Malis Hohn Moy

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  1. IP Switching for Scalable IP ServicesHassan M. AhmedRoss CallonAndrew G. MalisHohn Moy Presented by Gao, Yun Shih, Pei-Shin Wei, ShuGuang

  2. OUTLINE • Background Review & Motivation • The Overlay Model: Classical IP over ATM • IP Switching • IP Navigator • Conclusion

  3. Background Review & Motivation • Hop-by hop routing • Simplicity • Hierarchical Routing, easy to scaling • Difficult to implement Traffic Engineering (Bandwidth Management) & QoS

  4. Background Review & Motivation (Continued) • Switched Core • Achieve a form of Traffic Engineering • VC’s allows Explicit Routing to be used efficiently • Isolate the internal routing from changes of the Internet’s routing algorithms • Integration of Datagram and Circuit Technologies

  5. The Overlay Model: Classical IP over ATM • IP vs. ATM • Connectionless (IP) vs. connection oriented (ATM) • Packets (IP) vs. cells (ATM) • Broadcast LAN’s (IP) vs. point-to-point connections (ATM)

  6. The Overlay Model: Classical IP over ATM (Continued) • ATM Address Resolution Protocol (ATMARP) • Logical IP subnet (LIS) • Independent Routing Protocols

  7. LIS 2 LIS 3 LIS 2 LIS 3 Host A Host A LIS 1 Router 2 LIS 1 Router 2 Host C ATM SVC Host C Router 1 Router 1 Host B Host B Multiple IP LIS’s on one ATM network Connection between Hosts A and B

  8. The Overlay Model: Classical IP over ATM (Continued) • Logical IP subnet (LIS) • IP stations (hosts & routers) in the same LIS communicate directly via ATM SVC’s or PVC’s • IP stations in different LIS’s must intercommunicate via a router • Next Hop Resolution Protocol (NHRP) • Query / Response Model

  9. LIS 2 LIS 3 LIS 2 LIS 3 LIS 1 Host A Host A Router 2 LIS 1 ATM SVC Router 2 ATM SVC Host C Host C ATM SVC ATM SVC Router 1 Router 1 Host B Host B Connection between Hosts A and C Direct Connection between Hosts A and C (NHRP)

  10. The Overlay Model: Classical IP over ATM (Continued) • Scaling Problem • Total number of logical links that are advertised between the n ATM-attached routers equals

  11. IP Switching • Eliminating scaling problems by running the IP routing protocol on switches as well as routers

  12. IP Navigator • A particular IP switching implementation • Developed by Cascade Communication Corporation

  13. IP Navigator (Continued) • Makes a “cloud” of Cascade switches, frame relay, or ATM • Appears externally to be a collection of IP routers

  14. F E H D G I A C B

  15. IP Navigator (Continued) • Two routing instances are running inside the “cloud” • Uses standard IP routing (OSPF) within the core to exchange routing information • A VC routing protocol is running between switches, allowing them to build up point-to-point and point-to-multipoint VC’s

  16. IP Navigator (Continued) • Each router pre-establishes a VC to each potential egress (i.e. to every other router in the area) • Build point-to-multipoint (PMT) tree rooted at each egress • Traffic travels in reversed direction • VC’s used by IP Navigator are set up in response to routing packets and are automatically re-established as necessary

  17. IP Navigator (Continued) Multicast • Similar to unicast • Standard IP multicast protocol are spoken at the edge of the cloud • Multicast information is redistributed throughout the cloud using OSPF

  18. F E H D G I A C B Example of multipoint-to-point tree (MPT)

  19. QoS and Traffic Engineering • VC routing is based on dynamic routing algorithm • Explicit routing allows • Crankback and retry • Optimization of the combined path for multiple VC’s

  20. QoS and Traffic Engineering (Continued) • IP Navigator allows QoS support to be based on a range of coarse through fine granularity • Traditional “best efforts” IP service • Separates IP traffic into a small number of classes and open separate MPT’s for each class • First Class • Economy Class

  21. Conclusions • IP Navigator integrates the transport of connectionless IP traffic over connection-oriented switched data networks • Better scaling properties and inherent simplicity from IP • Higher performance of forwarding packets (VC’s)

  22. That's All !!!

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