Simulating Gnutella 0 6 Student Project Final Presentation

Simulating Gnutella 0. 6 Student Project Final Presentation Wei Lu 02. 2005 Communication Networks Wei Lu, Sireen Malik

Gnutella • Gnutella 0. 6 • Gnutella 0. 4 – Distributed Index Flooding Architecture (DIFA) – Signaling – Two-layered hierarchy • 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 knownhosts • Reverse routed QUERYHITS • 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 – File download via HTTP-TCP [Source: P 2 P Traffic Simulation, Sireen Malik, Prof. Ulrich Killat] Communication Networks Wei Lu, Sireen Malik 2

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). Communication Networks Wei Lu, Sireen Malik 3

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): Lime. Wire 30, Bear. Share 45. – Ultrapeer critera: “at least 15 KB/s downstream and 10 KB/s upstream”, “have been running for few hours/sever minutes”, “when (not) too many”… • Ultrapeer : ? %, Leaf: ? % Communication Networks Wei Lu, Sireen Malik 4

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) Communication Networks Wei Lu, Sireen Malik 5

Optimal Topology, Q 1 • 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{Query. Traffic[Query. Coverage(Pd, TTL)], Query. Hit. Traffic(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. Communication Networks Wei Lu, Sireen Malik 6

Optimal Topology, Q 2 • [3] gives rules of thumb. – But the model based on semi-p 2 p 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. Communication Networks Wei Lu, Sireen Malik 7

Optimal Topology, dynamic network • Most of above works are based on static context. • Peer availability matters. Communication Networks Wei Lu, Sireen Malik 8

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

Implementation, NS-2 • Extending Gnutella 0. 4: Ultrapeer Election, DIHA, Downloading, . . . • Facilities: control of selected peers, trace on link, random seed, . . . Communication Networks Wei Lu, Sireen Malik 10

Implementation, Ptolemy • Ptolemy – Adapting NS-2 code to Ptolemy. – No modification, just re-compile. Real World NS-2 Ptolemy Network Interface Node Adapter Star / Galaxy TCP Agent Adapter Star / Galaxy Gnutella Application Communication Networks Wei Lu, Sireen Malik Star / Galaxy 11

Configuration – User Model • All MODEM & DSL users in ON/OFF process – mean on 60 sec, log quadratic; mean off 105 sec, neg. exp. • Every 25 s, drops oldest connections when many • File size distribution: – for < 10 MB files (music) less than 15% bytes but more than 88% request – for >100 MB 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 Communication Networks Wei Lu, Sireen Malik 12

Configuration – Network • Germany Network, 17 core nodes. • Power Law for 2 nd level node connectivity (Pareto Distribution, Shape 1. 5) • Bandwidth of 2 nd level nodes (70% MODEM, Uniform Distribution) Communication Networks Wei Lu, Sireen Malik 13

Result – Average Signaling Traffic MODEM (100 Kbps) Communication Networks Wei Lu, Sireen Malik 14

Result – Average Singling Traffic DSL (1~4 Mbps) Communication Networks Wei Lu, Sireen Malik 15

Result – Average Signaling Traffic Bootstrap (1000 Mbps) Communication Networks Wei Lu, Sireen Malik 16

Result – Signaling Sum-up • MODEM(100 Kbps): 70%, DSL(1~4 Mbps): 29. 6% , Bootstrap(1000 Mbps) : 0. 4%. • 35>1/5% (5% peers behave as in 0. 4) – Less peers flood message. – Message flooded in smaller scope Communication Networks Wei Lu, Sireen Malik 17

Downloading • Previous configurations, e. g. File size distribution: • Each Query. Hit triggers a HTTP session for downloading. • Result: Query. Hit/Query = 34. 73% Communication Networks Wei Lu, Sireen Malik 18

Result – Gnutella 0. 6 Signaling and Signaling+Downloading • By single MODEM(100 Kbps) and DSL(1 Mbps) user • Signaling is minor part. • Log-Log scaled • MODEM: – Synthesis ≈ 100 Signaling • DSL: – Synthesis ≈ 1000 Signaling Communication Networks Wei Lu, Sireen Malik 19

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 Communication Networks Wei Lu, Sireen Malik 20