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Simulating Gnutella 0.6

Simulating Gnutella 0.6. Student Project Final Presentation Wei Lu 02.2005. Gnutella. Gnutella 0.6 Two-layered hierarchy Supernodes (called Ultrapeers) Client nodes (called Shielded Leaves)

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Simulating Gnutella 0.6

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  1. Simulating Gnutella 0.6 Student Project Final Presentation Wei Lu 02.2005

  2. Gnutella • Gnutella 0.6 • Two-layered hierarchy • Supernodes (called Ultrapeers) • Client nodes (called Shielded Leaves) • Ultrapeers: faster,better networking and CPU power act as proxies for client(leaf) nodes connected to them shield leaf nodes from almost all ping and query traffic • Gnutella 0.4 • Distributed Index Flooding Architecture (DIFA) • Signaling • Attempt connection with Bootstrap servers • Once connected, flood PINGS • Reverse routed PONGS from known-hosts • PONG-based connection to known hosts • Flood QUERIES to all known-hosts • Reverse routed QUERYHITS • File download via HTTP-TCP [Source:P2P Traffic Simulation, Sireen Malik, Prof. Ulrich Killat]

  3. Gnutella 0.6, Anti-flooding • Message Dispatching • Leaf node doesn't relay Ping message • Ultrapeer only dispatches Ping message to other connected Ultrapeers. • Query Routing • Leaf node doesn't spread Query message. • Ultrapeer only dispatches Query message to other Ultrapeer and some of his leaf nodes selectively (DIHA).

  4. Gnutella 0.6, Ultrapeer Election • New header fields for handshaking • X-Ultrapeer, whether a host plans on acting as ultrapeer • X-Ultrapeer-Needed, to balance the number of ultrapeers • Handshaking • Leaf to Ultrapeer, Leaf to Shielded Leaf, Leaf to Unshielded Leaf, Ultrapeer to Ultrapeer • Specification is quite open on details • Max-number of leaves (Cluster Size): LimeWire 30, BearShare 45. • Ultrapeer critera: “at least 15KB/s downstream and 10KB/s upstream”, “have been running for few hours/sever minutes”, “when (not) too many”… • Ultrapeer : ?%, Leaf: ?%

  5. Optimal Topology • What’s the globally optimal topology? (% of UltrapeerCluster size, Degree distribution, etc.) • How to locally approach the optimal topology?(Ultrapeer criteria, Routing protocol)

  6. Optimal Topology, Q1 • Analytic model: not well established yet. • Parameters • Ultrapeer percentage, Cluster Size, Degree distribution Pd, TTL, Query rate Rq, Replication rate Rr, … • Objectives • Load (Computation, Communication), Quality of result, … • Random Graph, Load{QueryTraffic[QueryCoverage(Pd, TTL)], QueryHitTraffic(Rr,Rq)}. Hard to calculate.[1] • Var(load(p)/CHL(p)), recursive function, simulated annealing to calculate.[2] • Measurement: strongly related to software configuration/ protocol implementation.

  7. Optimal Topology, Q2 • [3] gives rules of thumb. • But the model based on semi-p2p system (superpeer (server) is at most 1 hop away) might not be accurate enough. • Cluster head selection in ad-hoc and sensor network[4][5]. • Based on Node ID, Node degree. Optimize power consumption (load), communication, etc.

  8. Optimal Topology, dynamic network • Most of above works are based on static context. • Peer availability matters.

  9. Current Approach • Related to Implementation[Daniel Stutzbach, Reza Rejaie, “Characterizing Today’s Gnutella Topology”, Dec.2004] • Our config:5% Ultrapeer.

  10. Implementation, NS-2 • Extending Gnutella 0.4: Ultrapeer Election, DIHA, Downloading, ... • Facilities: control of selected peers, trace on link, random seed, ...

  11. Adapter Adapter Implementation, Ptolemy • Ptolemy • Adapting NS-2 code to Ptolemy. • No modification, just re-compile.

  12. Configuration – User Model • All MODEM & DSL users in ON/OFF process • mean on 60 sec, log quadratic; mean off 105 sec, neg. exp. • Every 25s, drops oldest connections when many • File size distribution: • for < 10MB files (music) less than 15% bytes but more than 88% request • for >100MB files (movies) more than 65% bytes but less than 5% request • Number of files shared by peers • 66% free-riders, 73% share 10 or less files, top 1% share 35% files

  13. Configuration – Network • Germany Network, 17 core nodes. • Power Law for 2nd level node connectivity (Pareto Distribution, Shape 1.5) • Bandwidth of 2nd level nodes (70% MODEM, Uniform Distribution)

  14. Result – Average Signaling Traffic MODEM (100Kbps)

  15. Result – Average Singling Traffic DSL (1~4Mbps)

  16. Result – Average Signaling Traffic Bootstrap (1000Mbps)

  17. Result – Signaling Sum-up • MODEM(100Kbps): 70%, DSL(1~4Mbps): 29.6% , Bootstrap(1000Mbps) : 0.4%. • 35>1/5% (5% peers behave as in 0.4) • Less peers flood message. • Message flooded in smaller scope

  18. Downloading • Previous configurations, e.g. File size distribution: • Each QueryHit triggers a HTTP session for downloading. • Result: QueryHit/Query = 34.73%

  19. Result – Gnutella 0.6 Signaling and Signaling+Downloading • By single MODEM(100Kbps) and DSL(1Mbps) user • Signaling is minor part. • Log-Log scaled • MODEM: • Synthesis ≈ 100 Signaling • DSL: • Synthesis ≈ 1000 Signaling

  20. References • [1] Ruediger Schollmeier, Gero Schollmeier, An analytic model for the behavior of arbitary peer-to-peer networks. • [2] Mudhakar Srivatsa, Bugra Gedik, Ling Liu, Improving Peer to Peer Search With Multi-tier Capability-Aware Overlay Topologies. • [3] Beverly Yang, Hector Garcia-Molina, Designing a Super-Peer Network • [4] Mario Gerla,Jack Tzu-Chieh Tsai, Multicluster, mobile, multimedia radio network • [5] Ossama Younis, Sonia Fahmy, Distributed Clustering in Ad-hoc Sensor Networks: A Hybrid, Energy-Efficient Approach

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