Copyright (C) 2006-2014 David Sugar, Tycho Softworks.
Copyright (C) 2015-2017 Cherokees of Idaho.

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.  The
server directory includes some basic example server configurations.

OUR GOALS:

The goal of this package is to individuals and organizations to communicate
securely whether in private or peer-to-peer over the public Internet without
intermediary service providers.  This package can also operate as a pure SIP
based office telephone call server supporting generic phone system features
like call forwarding, hunt groups and call distribution, call coverage and ring
groups, holding and call transfer, as well as offering SIP specific
capabilities such as presence and messaging.  Support for using secure
telephone extensions, for placing and receiving peer-to-peer calls directly
over the internet, and intercept/decrypt-free peer-to-peer audio is also being
incorporated into the sipwitch design.

Our goal includes creating 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 peer-to-peer 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.

WHAT IS SIPWITCH:

GNU SIP Witch is a peer-to-peer VoIP server for the SIP protocol. As a VoIP
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.  This also means GNU SIP Witch can act as a secure
calling server where all peers directly maintain peer encrypted sessions
without central supervision of keys or central decryption of media traffic.

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 multi-protocol telephone server or IP-PBX, and does not
try to address the same things like asterisk, freeswitch, yate, all of which
require direct media processing.  Instead, GNU SIP Witch focuses on doing one
thing as a pure SIP call server, and is being developed specifically to do
that one thing very well.  Our goal is to focus on achieving a network scalable
telephone architecture that can be deeply embedded, which can support secure
calling nodes, and that can integrate well with other SIP based/standards
compliant components.

SUPPORT:

Resources for supporting GNU SIP Witch will be consolidated and handled
principally through Savannah using the existing GNU Telecom subsystem project
found there (https://savannah.gnu.org/projects/gnucomm) as a central point of
contact. This sub-project is being reorganized for this purpose.  In addition
the sipwitch-devel@gnu.org mailing list can be used to submit patches or
report bugs.

REQUIREMENTS:

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 Version 3 or later.

CONTRIBUTING:

The primary development mailing list is sipwitch-devel@gnu.org

For those looking to write faq's or howto's, I could suggest using our wiki,
http://www.gnutelephony.org

We are requiring any non-trivial contributions to the code base be copyright
assigned to the FSF.  It is of course necessary to have a limited set of
copyright holders who share common interest (some do strongly suggest having a
single copyright holder for this purpose; I personally have prefer two...), and
it is necessary to have a trustable third party when asking people to do
copyright assignment.  To me the FSF meets these goals perfectly, and this I
think helps assure people the codebase cannot later be taken private or
otherwise used in ways "not anticipated" if they do assign copyright.