Peertopeer and Wi Fi Jon Crowcroft The Computer

Peer-to-peer and Wi. Fi Jon Crowcroft The Computer Laboratory University of Cambridge jon. crowcroft@cl. cam. ac. uk 1

People and Projects in Cambridge • Faculty: • Jon Crowcroft, Ian Pratt • Research Staff: • Sven Ostring, + • Ph. Ds: • Rajiv Chakravorty & Meng How Lim • Projects: • COM(vodafone) • CMI • Mobile. MAN 2

Mobileman Kickoff Meeting Pisa, 5/11/02 • P 2 P & Wi. Fi • Spectrum Economics 3

Analysis of Self Organisation • It has been noted that peer-to-peer and ad hoc wireless networks both use techniques of self organisation • We would like to examine this similarity properly • Analyse which particular techniques are useful (e. g. routing, load management, etc) • See if we can create a next generation ad hoc wireless net – one step beyond the 2 level system in terminode networks (perimiter + spine) • Infocom + followup proxinet paper…soar? 4

Location Services Experiment • P 2 p makes use of techniques such as consistent hashing, rabin fingerprints, bloom filters and so on, for mapping key to location • Perhaps a similar model could be used for addressing • Would note that these often lead to very poor latency • Techniques such as landmarks, shortcuts, lighthouse, chord etc are worth looking at • Paper submitted to IPTPS on “lighthouses” 5

Notification Services • Could look at Scribe (P 2 P based Event service based on Pastry) • Could look at event services as driving model – could be information or applications like games…. • Problem of effort levels! • Have to enlist Ph. Ds at cambridge!!!… 6

Performance Enhancing Overlays • P 2 p and overlays are dual. • We would like to look at the interaction between overlays and underlying mobile/wireless dynamics • We have looked at a system of TCP proxies to mitigate performance problems in wireless access nets (have Infocom 03 paper on this) – we could extend this to ad hoc multi-hop/multi-path systems too • Other overlays (e. g. application specific routing and trans-coders etc are of interest too. 7

Cambridge Mobileman P 2 P Research Topics • Analysis • Experimental Application Platform • Tests for Performance 8

Relevant p 2 p technologies • Pastry/Scribe/Xenostore – • Storage, notification, searching • Consistent Hash + location • Eternity, Freenet • Privacy, persistence, caching • Robustness • Rabin fingerprint, bloom filter • ALAN/Overqos/RON • App level routing 9