Draft Charter for the P2PSIP WG

Revised September 20, 2006 -- NEWER VERSION AVAILABLE

New revision from November 3, 2006 is available.

Peer-to-Peer Session Initiation Protocol (P2PSIP)


RAI Area Director(s):
Cullen Jennings
Jon Peterson

RAI Area Advisor:
Cullen Jennings

Mailing Lists:
General Discussion: p2p-sip@cs.columbia.edu
Subscribe at: http://lists.cs.columbia.edu/mailman/listinfo/p2p-sip
Archive at: http://lists.cs.columbia.edu/pipermail/p2p-sip/

Description of the Working Group:

The Peer-to-Peer (P2P) Session Initiation Protocol working group
(P2PSIP WG) is chartered to develop protocols and mechanisms for the
use of the Session Initiation Protocol (SIP) in settings where the
service of establishing and managing sessions is principally handled 
by a collection of intelligent endpoints, or P2PSIP overlay peers,
rather than centralized servers as in client-server SIP as currently
deployed. A number of cases where such an architecture is desirable
have been documented in [1].

The terminology and concepts draft [2] explains the terms and concepts
used here. The work focuses on collections of nodes called "P2PSIP
overlay peers" and "P2PSIP overlay clients". P2PSIP overlay peers
manifest a distributed namespace in which overlay users are identified
and provides mechanisms for locating users or resources within the
P2PSIP overlay. P2PSIP overlay clients  and peers use the resolution
services of the peers as an alternative to the SIP correspondent
discovery process of RFC 3263. Session management, messaging, and
presence functions are performed using traditional SIP.

This group's primary tasks are to produce:

1. An overview document explaining concepts, terminology, rationale,
   and illustrative use cases for the remaining work. 
2. A proposed standard defining a P2PSIP Overlay Peer Protocol. This
   protocol is used between P2PSIP overlay peers, some of which may be
   behind NATs. This protocol will define how the P2PSIP overlay peers
   collectively provide for user and resource location in a SIP
   environment with no or minimal centralized serves. This protocol may
   or may not be syntactically based on SIP, a decision to be made by the
   WG. The group will identify and require one base P2P algorithm (likely
   a particular Distributed Hash Table (DHT) algorithm), while allowing
   for additional optional algorithms in the future. 

3. A proposed standard defining a P2PSIP Overlay Client Protocol for
   use by P2PSIP overlay clients, some of which may be behind NATs. This
   protocol will define how the P2PSIP overlay clients query and/or
   modify, the resource location information of the overlay. While
   clearly a logical subset of the P2PSIP Overlay Protocol, the WG will
   determine if the client protocol is a syntactic subset of the peer 
   protocol, and whether the client protocol has SIP based syntax.

4. An architecture document. This document will address how the
   protocols defined above, along with existing IETF protocols, can be
   used to produce systems to locate a user, identify appropriate
   resources to facilitate communications (for example media relays), and
   establish communications between the users, without relying on
   centralized servers. 

The work planned for the P2PSIP working group is distinct from, but
requires close participation with other IETF WGs, particularly SIP,
SIPPING, SIMPLE, BEHAVE and MMUSIC. The group cannot modify the
baseline SIP behavior, define a new version of SIP, or attempt to
produce a parallel protocol for session establishment. If the group
determines that any capabilities requiring an extension to SIP are
needed, the group will seek to define such extensions within the SIP
working group using the SIP change process (RFC 3427). Similarly,
existing tools developed in the BEHAVE and MMUSIC groups will be used
for NAT traversal, with extensions or changes desired to support
P2PSIP created in these groups. 

The working group takes it as an unfortunate fact that NATs and
firewalls exist in the Internet, and will ensure that the protocols
produced work in their presence as much as possible. Similarly, the
group will attempt not to make design decisions that preclude
anonymous communications systems from being crafted using the
protocols defined by this WG.

The following topics are excluded from the Working Group's scope:

1. Issues specific to applications other than locating users and
   resources for SIP-based communications and presence.

2. Solving "research" type questions related to P2PSIP or P2P in
   general. The WG will instead forward such work to the IRTF. Examples
   include fully distributed schemes for assuring unique user identities
   and the development of P2P-based replacements for DNS. 

3. Locating resources based on something other than URIs.In other
   words, arbitrary search of attributes is out of scope, but locating
   resources based on their URIs is in scope. 

4. Multicast and dynamic DNS based approaches for locating users and resources.

Goals and Milestones

Sep 2007        Submit P2PSIP overview document to the IESG (Informational)

Sep 2008        Submit P2PSIP overlay client protocol document to the IESG (Standards track)

Sep 2008        Submit P2PSIP overlay peer protocol document to the IESG (Standards track)

May 2009        Submit P2PSIP architecture document to the IESG (Standards track)


[1] D. Bryan, E. Shim, B. B. Lowekamp, "Use Cases for Peer-to-Peer
    Session Initiation Protocol (P2PSIP)",
    draft-bryan-sipping-p2p-usecases-00.txt, November 29, 2005 

[2] D. Willis, D. Bryan, P. Matthews, E. Shim, "Concepts and
    Terminology for Peer to Peer SIP," draft-willis-p2psip-concepts-01.txt
    (work-in-progress), August 18, 2006 

Page maintained by David A. Bryan (dbryan at p2psip dot org) and Tiffany Broadbent (tbroadbent at p2psip dot org).
Thanks to the many people who have contributed links to this site.
Last modified: 3 July, 2009