Mobileman

Peer-to-peer and WiFi

Jon Crowcroft

The Computer Laboratory

University of Cambridge

jon.crowcroft@cl.cam.ac.uk

Mobileman

People and Projects in Cambridge

• Faculty: • Jon Crowcroft, Ian Pratt

• Research Staff: • Sven Ostring, +

• PhDs: • Rajiv Chakravorty & Meng How Lim

• Projects: • COM(vodafone)• CMI• MobileMAN

Mobileman

Mobileman Kickoff MeetingPisa, 5/11/02

• P2P & WiFi• Spectrum Economics

Mobileman

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?

Mobileman

Location Services Experiment

• P2p 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”

Mobileman

Notification Services

• Could look at Scribe (P2P 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 PhDs at cambridge!!!…

Mobileman

Performance Enhancing Overlays

• P2p 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.

Mobileman

Cambridge Mobileman P2P Research Topics

• Analysis• Experimental Application Platform• Tests for Performance

Mobileman

Relevant p2p 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