SIP in higher education

[(Dennis Baron)]

SIP.edu Conference Call, November 2nd 2006

*Attendees*

Dennis Baron, MIT
Justin Church, UNC
Alan Crosswell, Columbia
Mike Freston
Candace Holman, Harvard
Daniel-Constantin Mierla, OpenSER
Scott Morningstar, UNC
Christian Schlatter, UNC
Leo O'Shea, Boston College
Philippe Sultan, Inria
Ben Teitelbaum, Internet 2
Chris Trown, University of Oregon
Garrett Yoshimi, University of Hawaii

*Discussion*

Today's call begins with Ben's announcement that he is leaving
Internet 2 for a position at BitTorrent.

The remainder of the call featured an overview of OpenSER with
developer Daniel-Constantin Mierla. Recent enhancements in version 1.1
include support for geographic distribution, a cacheless mode for
using multiple databases in different locations, POTS support, NAT
enhancements, and a stateless proxy mode for load balancing multiple
requests. Various modules have been improved, including one which
provides dialog support. Currently this is mostly used for statistics
but ideally would be used to implement a stateful call proxy at the
signaling level, avoiding the media stream.

Configuration of TLS has been improved and allows more
flexibility. Additionally, the developers are looking to add multiple
domain support with TLS, which has been incorporated into GnuTLS and
the development version of OpenSSL. At the handshake, the domain to be
accessed would be passed and the server would send back the proper
certificates, allowing the use of multiple domains without having to
use multiple proxies or ports.

Other improvements include more access to server internals, scripting
variables, a module with support for signaling interception, SIP trace
to monitor incoming and outgoing requests, and support for more
databases using ODBC drivers.

In the latest development version, an XMPP module is included. This
module acts as a Jabber server and does translation based on domain
names. They are looking to integrate SIP and XMPP presence, and a new
module should be available in a few weeks. The development version
also includes a new management interface that replaces the existing
Unix sockets, which have been moved to modules.  XML-RPC and HTTP
support is planned to be for the next release, XML-RPC should be
pushed to CVS in the next weeks. The they will start working on
HTTP. Other improvements include an improved presence module, support
for secure peering and trust relationships between peers to limit
undesired calls, an SNMP module, global AVPs, and more configuration
and setup tools. This new release should be available in January or
February, with future releases coming every six to eight months.

Christian asks about the global AVPs, wondering if they are per
transaction or global for all transactions. Daniel says that they are
global for all processes, and not bound to a particular
transaction. It should be possible to use the global AVPs in an on
reply route. This has presented some difficulties, and the developers
are trying come up with a system to implement this.

Christian also asks about SRV-based failover. Currently the support
for this is half complete, as SRV and NAPTR are supported but not
stored and reused. Daniel says that this should be fully implemented
in the next release.

Dennis asks about the major users of OpenSER and who influences the
development of new features. Daniel says that there are a variety of
contributor who develop features that they personally need. The
company he works for does not offer OpenSER as a service, but they
offer support and consultation to service providers. Dennis also asks
about support for the SIP identity RFC for signing SIP
messages. Daniel says that there has been no work on this yet, but he
believes that there may a module in development. This is hard to test
on the server side without clients to sign messages.

Finally, Daniel is asked about getting involved with development or
influencing the future of OpenSER. Daniel says that the

 mailing list is the main channel. As for support,
main channel is 

 mailing list and the forum at
voipuser.org is also a very good alternative.