1. draft-bryan-sipping-p2p David Bryan IETF 63, Paris August 3, 2005

2. Current State of Draft Draft revised July 15 This is still a straw man, proposal to encourage discussion and document our research Most important changes were revisions to the explanatory sections –Attempted to clarify some of the sections that were confusing –Lots of mechanism in the draft, but explanation text is most important –Syntax changes include changing how URIs are handled (move toward URI parameters) and modifying the headers defined in draft to correspond Still much to be done –Identify the limitations, pro-cons of different approaches –Identity problem

3. Basic Overview Essentially, proposal replaces centralized registrar with cooperating nodes Defines a DHT based approach, loosely based on Chord –Changed to be iterative, rather than recursive –Hosting node replies on its own behalf, not successors SIP REGISTER overloaded to allow not only user registrations, but node registrations (DHT operations) Uses buddy list/phone book to augment search Several uses we are interested in –Small organizations –Emergency scenarios –Large scale communication

4. Implementation Have working prototype supporting our current draft, based on reSIProcate stack Using implementation to verify the concepts in the draft work, explore different routing algorithms –Lots of alternatives, Communications systems are fundamentally different from file sharing Less resources stored per user Latency more important Guaranteed query completion/accuracy

5. Work to be done SIP w/some DHT for lookup or implement DHT using SIP? (we do later) Media/NAT issues Distributed identity Security –Prevent spoofing, prevent squatting IDs, don’t enable illegal file sharing or DOS attacks Routing algorithms designed for P2P communications –Supernodes, ICE, Turn servers? Likely first step is to figure out all the places that P2P may be useful for SIP and create a draft defining the problem space

6. References draft-bryan-sipping-p2p-01 D. A. Bryan, B. B. Lowekamp and C. Jennings, SOSIMPLE: Towards a Serverless, Standards-based, P2P Communication System, AAA-IDEA, June 2005 Stoica et al., Chord: A Scalable Peer-to-Peer Lookup Protocol for Internet Applications, IEEE/ACM Transactions on Networking (to appear) –(Don’t use the algorithms from SIGCOMM paper by same authors with same title – it contains some algorithmic errors) I maintain a list of references at http://www.p2psip.org Contact me via email bryan [at] ethernot [dot] org