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GNU Telecom Subsystem (GNU Telephony)

GNU SIP Witch Introduced

SIP Witch is an official package of the GNU Project as of August 10th 2007. GNU SIP Witch is also part of GNU Telephony & the GNU Telecom subsystem.

GNU SIP Witch is a call and registration server for the SIP protocol. As a call server it services call registration for SIP devices and destination routing through SIP gateways. GNU SIP Witch does not perform codec operations or media proxying and thereby enables SIP endpoints to directly peer negotiate call setting and process peer to peer media streaming even when when multiple SIP Witch call nodes at multiple locations are involved. This means GNU SIP Witch operates without introducing additional media latency or offering a central point for media capture.

GNU SIP Witch is designed to support network scaling of telephony services, rather than the heavily compute-bound solutions we find in use today. This means a call node has a local authentication/registration database, and this will be mirrored, so that any active call node in a cluster will be able to accept and service a call. This allows for the possibility of live failover support in the future as well.

GNU SIP Witch is not a SIP "router", and does not try to address the same things as a project like iptel "Ser". GNU SIP Witch is being designed to create on-premise SIP telephone systems, telecenter servers, and Internet hosted SIP telephone systems. One important feature will include use of URI routing to support direct peer to peer calls between service domains over the public internet without needing mediation of an intermediary "service provider" so that people can publish and call sip: uri's unconstrained. GNU SIP Witch is about freedom to communicate and the removal of artifical barriers and constraints whether imposed by monopoly service providers or by governments.

GNU SIP Witch depends on the UCommon library, which may merge with and become GNU Common C++ 2.0 later this year or early next year. CVS for and new distributions of UCommon will be found in the GNU Telecom project on an interim basis until then. GNU SIP Witch also uses libeXosip2 and GNU oSIP, and these may be found at their respective sites. GNU SIP Witch is licensed under the GNU General Public License V3 or later.

What is GNUCOMM?

GNUCOMM is the Telecom subsystem of the GNU Project. The goal of GNUCOMM is to deliver scalable telephony services for current and next generation telephone networks using entirely free software on the GNU system.

What is GNU Bayonne?

GNU Bayonne is the telephone server of the GNU Project. It offers scalable media and scripted voice application services for SIP and H.323 networks as well as for traditional PSTN and ISDN services. GNU Bayonne may be used stand-alone to deliver carrier hosted or premise application services behind existing switching equipment and standard compliant VOIP platforms, or together with GNU SIP Witch and perhaps Troll to offer complete VOIP phone systems.

What is GNU SIP Witch?

GNU SIP Witch is the VOIP call, provisioning, and feature server of the GNU Project. It offers network scalable services through SIP. GNU SIP Witch only offers registration services and only performs destination selection and routing. GNU SIP Witch uses SIP to resolve media streaming by endpoints. This means GNU SIP Witch is neither inhibited by restrictive codec patents nor imposes additional media latency in VOIP networks.

GNUComm System Design Overview

Version 0.6 of the GNUComm System Design Overview is now available. It is currently being maintained by rsb. Check it out.

This needs to be revised...

GNUComm Components

Release versions of some GNUComm Components are already available:

Active Projects:

Inactive Projects:

Proposed Projects:


Get the Software

GNU Bayonne and all related packages may be found at ftp.gnu.org. GNU SIPWitch is available only from project cvs at the moment, but we expect an initial distribution sometime before the end of the year. All GNUCOMM & GNU Telephony software will be offered licensed under the GNU General Public License V3 or later.

Mailing Lists and Other Resources

The canonical set of GNU mailing lists have been set up for GNUCOMM:

We also maintain a GNU Telephony wiki.

CVS Access

These instructions are available for anonymous cvs access.

Contact information

The current coordinators for the project are <richbodo at gmail dot com> and <dyfet at gnu dot org>


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