SIP-Session Initiation Protocol

Session Initiation Protocol (SIP) (From Hennning Schulzrinne)
SIP Pages (Martin's SIP page... Nice implementation links)
Documents

Implementations
SIP Implementations (From Hennning Schulzrinne)

Swik SIP

Vovida.org
Vocal SIP Stack ( the overall architecture of Vocal SIP stack)

Sofia-SIP Library (Sofia-SIP is based on a SIP stack developed at the Nokia Research Center)

SIPfoundry is an international open source software community dedicated to accelerating the adoption of SIP based VoIP solutions.
sipXtackLib - transaction stateful SIP stack
reSIProcate - a stack and a small collection of applications.

Articles
OSIP: An Open Source SIP Architecture
Software Design Overview Template

Products

Softphone
Integrated SoftTech Solutions

SIP Call Flows
Cisco
HP
VOCAL Technology Overview: Basic Call Flow
http://www.ietf.org/rfc/rfc3665.txt
http://www.iptel.org/info/players/ietf/callflows/
http://www.voip-info.org/wiki/view/SIP
Tech Invite -- RFC3666 SIP PSTN Call Flows Revisited (Good)
RFC 3665 - SIP Basic Call Flow Examples - http://ietf.org/rfc/rfc3665.txt * RFC 3666 - SIP PSTN Call Flows - http://ietf.org/rfc/rfc3666.txt * http://cisco.com/en/US/products/sw/iosswrel/ps1835/products_programming_reference_guide_book09186a0080080221.html

Microsoft Real-Time Communications: Protocols and Technologies
SIP Call Flow Examples
http://www.voip-news.com/sp/cci/sip.htm
Microsoft PowerPoint - 20040616-george-identity.ppt
SIP, Standards, Features and Security
External Call Control using SipExchange
Telefocal Asia - Hands-on VoIP with SIP (Session Initiation Protocol)
SIP: Creating next-generation telecom applications
SIP/SIP-T User Agent
JRC成果報告