P2P

1
P2P

• Cullen Jennings
• fluffy_at_cisco.com

2
Out of scope

• Mechanisms
• File Sharing
• Fluffys Hair
• XCAP

3
P2P What

• Media relays
• Storing buddy list / address book
• Rendezvous
• Storing voice mail
• Anonymization of media
• Small PBX system

4
Properties Interesting

• No central server
• No infrastructure
• Reduced Op/Ex
• Anonymous communications
• Scalability
• Reliability

5
Types of P2P Systems

• Type D Use DNS but client to client
• normal sip call directly between UA
• unix talk
• Type C Hybrid supernode clients
• normal sip with proxy
• napster
• Type B Occasional DNS
• use DNS to get into system but after than just
  use P2P mechanism
• gnutella
• Type A no reliance on central servers (no DNS)
• adhoc rendezvous based IM in ichat

6
Security Properties

• Hard to stop your name form being stolen
• Hard to guarantee no duplicate names
• No single server can take you down
• DOS?
• Admin Fat Fingers config
• RIAA shuts you down
• Anonymization with no server to subpoena

7
Trust Model of Internet

• Trust of names based on DNS and delegation of
  hierarchy
• CA names are an example of this
• SSH, email, PGP use names
• Names connect the internet to humans
• Make assumptions about crypto stuff
• Largely assumes secure/not secure (binary)
• Stretched our mind to do leap of faith system

8
Trust Models of P2P

• Statistical likelihood prediction of security
• Assumptions very dubious based on general mix of
  existing good/evil in the network
• May not be able to generate unique names

9
Properties of Names Rings

• Would be nice to
• Control what ring you join
• Be able to merge rings without name changing
• Be able to move back and forth between
  traditional DNS SIP AOR and ring name
• TradSip can reach ring dwellers

10
Supernode Characteristics

• How to find ones that are
• stable, stay up persistent
• can store stuff
• topologically the right place

11
Rings and Rings That Bind Them

• Simple systems seem to start with single ring
• More complex systems seem to put super nodes at
  one level in ring and run some sub

12
IETF Drafts

• David A. Bryan and Cullen Jennings A P2P
  Approach to SIP Registration draft
• draft-bryan-sipping-p2p-00
• Alan Johnston SIP, P2P and Internet
  Communications
• draft-johnston-sipping-p2p-ipcom-00
• P. Matthews and B. Poustchi Industrial-Strength
  P2P SIP
• draft-matthews-sipping-p2p-industrial-strength-00

13
Web Pages

• www.p2psip.org
• Lots of links to P2P SIP resources
• Link to the WM Technical Report Bryan and
  Lowekamp, SOSIMPLE A SIP/SIMPLE Based P2P VoIP
  and IM System (technical report, older than our
  draft!)
• www1.cs.columbia.edu/kns10/research/p2p-sip
• several technical reports
• Columbia Technical Report Singh and Schulzrinne,
  Peer-to-Peer Internet Telephony using SIP
  (technical report)

14
References

• Stoica et al., Chord A scalable peer-to-peer
  lookup service for internet applications
• Rowstron and Druschel, Pastry Scalable,
  Decentralized Object Location, and Routing for
  Large-Scale Peer-to-Peer Systems
• Guha, Takeda and Francis, NUTSS A SIP-based
  Approach to UDP and TCP Network Connectivity
• Castro et al., Secure Routing for Structured
  Peer-to-Peer Overlay Networks
• Dabek et al., Designing a DHT for Low Latency and
  High Throughput