OSIP

oSIP is a free software library for VoIP applications implementing lower layers of Session Initiation Protocol (SIP). The library includes the minimal codebase required by any SIP application and offers enough flexibility to implement any SIP extension or behavior. Started in September 2000 and published in April 2001, oSIP is among the oldest SIP open source stack still being developed and maintained. The project was made part of the GNU Project as GNU oSIP in 2002.

OSIP

Original author(s)	Aymeric Moizard
Developer(s)	Antisip SARL
Stable release	5.1.1 / January 17, 2020; 4 years ago (2020-01-17)
Repository	git.savannah.gnu.org/cgit/osip.git
Written in	C
Operating system	Windows, macOS, Linux, FreeBSD, iOS, Android, BlackBerry OS
Type	Voice over IP, instant messaging, videoconferencing
License	GNU LGPL version 2
Website	osip.org

Software using oSIP

• eXosip, the "eXtended osip" library. An extension of oSIP for softphone implementation written by Aymeric Moizard.
• GNU SIP Witch

Software that used oSIP

• Linphone. Linphone has been the first project based on oSIP and eXosip.
• Jami (software).
• FreeSWITCH.

Usage in academic research

• Yang, Yang (2007). SIP over Client Initiated Connections (Thesis). Helsinki University of Technology. Archived from the original on 2016-04-02. Retrieved 2014-01-29.
• Burgy, Laurent (2008). Approche langage au développement du support protocolaire d'applications réseaux (PDF) (Thesis). University of Bordeaux 1.
• Dai, H B (2008). Theory and Implementation of VoIP Based SIP Protocol (Thesis). Chinese Geology University (Beijing).
• Wang, H (2008). The Design and Development of IP Phone's Added-Vale Services Based on SIP Protocol (Thesis). Beijing University of Posts and Telecommunications.
• SongYuNa (2009). The Research and Development of Embedded VoIP Gateway Based on IXP425 (Thesis). Tianjin University.
• Zhang, Z H (2010). Research And Implementation Of IP Phone Terminal Based On SIP Protocol (Thesis).

See also

• Free and open-source software portal

• List of SIP software

References

• "Free VoIP Software Development Libraries". Retrieved 2014-01-11.
• GNU oSIP Library Brave Gnu World Archived 2014-05-17 at the Wayback Machine Linux Magazine 2002 Issue 22, page 97.
• The Essential Guide to Open-Source VoIP Archived 2018-06-25 at the Wayback Machine VoIP News Mar 12, 2008
• Principios de VoIP (in Portuguese) (brief mention), Linux Magazine Brazil #3, pages 25 & 26