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RVS Seminar SS 2002

RVS Seminar SS 2002. Performance Simulation of a Multicast Protocol for Small Conferences. Today‘s Presentation. The Diploma Thesis Multicast for Small Conferences The ns-2 Network Simulation Software Status Simulation Questions / Discussion. Diploma Thesis.

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RVS Seminar SS 2002

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  1. RVS Seminar SS 2002 Performance Simulation of a Multicast Protocol for Small Conferences

  2. Today‘s Presentation • The Diploma Thesis • Multicast for Small Conferences • The ns-2 Network Simulation Software • Status • Simulation • Questions / Discussion

  3. Diploma Thesis • Performance Simulation of a Multicast Protocol for Small Conferences • Part I: Building/Modifying ns-2 Modules • Part II: Performance Simulation

  4. Multicast for Small Conferences Report IAM-00-008 (T. Braun) Topic: Definition of a scalable multicast concept that can be used for small conferencing groups in the internet (especially telephone/audio conferences). Goal: Reduction of routing table overhead (compared to native multicast)

  5. MSC packet format • IPv6 destination address field contains unicast address of the nearest recipient • an IPv6 routing header carries the unicast addresses of all other recipient plus the multicast address

  6. MSC end systems / gateways • On sending: creation of an MSC packet • On receiving: • copy the multicast address into the destination field • remove the routing header • forward to higher level protocols / local receiver group • if more unicast addresses are present: remove own address, re-send the packet

  7. MSC routers • Non-MSC routers: ignore routing header • MSC-capable routers • analyse destination field and routing header • split address list and duplicate packet if members are reached via different outgoing interfaces • duplicate packet if a branch occurs after a few hops - but how does the router know this?

  8. The ns-2 Network Simulator • De facto standard simulation software for academic research • Part of the VINT (Virtual InterNet Testbed) project (USC/ISI); current version developed since 1995 • Website: http://www.isi.edu/nsnam/

  9. ns-2 technology • Simulation scripts in OTcl • Coded in OTcl and C++ • analysis: tracefiles • visualization: NAM (Network Animator)

  10. ns-2 advantages • Extensive documentation (~350 pages) • Some additional tutorials • Marc Greis’s Tutorial on ns-2 • ns-2 by Example • lots of users worldwide, mailing list (archive) • specialized modules for LAN, mobile networking, satellite networking, ad-hoc networking

  11. ns-2 disadvantages • mixed coding in OTcl/C++ makes the code hard to understand • very few useful comments in the code • frequent changes in the software, documentation not always up to date • structure sometimes illogical (no real-world components)

  12. Completed Work • PART I: • ns-2 agent (sender/receiver) for end system MSC simulation • ns-2 classifier for MSC router simulation • (almost) classifier to simulate an MSC/native multicast gateway • PART II: real-world data for the simulation (topology, delays, routing)

  13. Real-World Topology • Backbone networks: Switch, Géant (Europe), Garr (Italy), Abilene (USA) • End systems: University web servers • Delays measured using ping and traceroute from different looking glasses • Transformation into an ns-2 topology with 77 nodes

  14. Next step: Simulation • Parameters: group size, group distribution (clustering), number/distribution of MSC-capable routers • comparison with native Multicast/explicit Multicast in terms of bandwidth usage, delay, protocol overhead

  15. Questions / Discussion

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