Personal Collaboration Network Resources

Peer-to-Peer Internet Telephony using SIP
Kundan Singh and Henning Schulzrinne
Department of Computer Science, Columbia University

SIPPEER: A Session Initiation Protocol (SIP)-based Peer-to-Peer Internet Telephony Client Adaptor
Kundan Singh and Henning Schulzrinne
Department of Computer Science, Columbia University

SIPShare
SIP Beyond Voice and Video Standards-based Distributed Networking from EarthLink Research and Development

Open source sip stack
Discussion on the <Sip-implementors> mailing list.

p2pSip.org
"The idea of P2P SIP is to leverage P2P technology for resource discovery in a SIP network. Connecting SIP nodes with a P2P overlay network removes the need for a central server, while still allowing for communication between the nodes."

SIP Implementations
Dept. of Computer Science at Columbia list of SIP implementations.

SIPforum.com
The SIP Forum's mission is to advance the adoption of products and services based on the Session Initiation Protocol - SIP.

Vovida.org
A communications community site dedicated to providing a forum for open source software used in datacom and telecom environments.

The GNU oSIP library
SIP stands for the Session Initiation Protocol and is described by the rfc3261 (which deprecates rfc2543). This library aims to provide multimedia and telecom software developers an easy and powerful interface to initiate and control SIP based sessions in their applications. SIP is a open standard replacement from IETF for H323.

SIPcenter.com
Lots of SIP resources.