iptel.org SIP Express Router (ser)
SIP Express Router (SER) is an industrial-strength, free VoIP server
based on the session initiation protocol (SIP RFC2543-bis). It is
engineered to power IP telephony infrastructures up to large scale. The
server keeps track of users, sets up VoIP sessions, relays instant
messages and creates space for new plug-in applications. Its proven
interoperability guarantees seamless integration with components from
other vendors, eliminating the risk of a single-vendor trap. It has
successfully participated in various interoperability tests in which it
worked with the products of other leading SIP vendors.
The SIP Express Router enables a flexible plug-in model for new
applications: Third parties can easily link their plug-ins with the
server code and provide thereby advanced and customized services.
Its performance and robustness allows it to serve millions of users and
accommodate needs of very large operators. With a $3000 dual-CPU, the SIP
Express Router is able to power IP telephony services in an area as large
as the Bay Area during peak hours. Even on an IPAQ PDA, the server
withstands 150 calls per second (CPS)! The server has been powering our
iptel.org free SIP site withstanding heavy daily load that is further
increasing with the popularity of Microsoft's Messenger.
The SIP Express Router is extremely configurable to allow the creation of
various routing and admission policies as well as setting up new and
customized services. Its configurability allows it to serve many roles:
network security barrier, application server, or PSTN gateway guard for
2. Feature List
See http://www.iptel.org/ser/features for an updated feature list.
Note that as features easily are added as modules, changes can
Most of SER features are implemented as plug-in modules. See
http://www.iptel.org/views/tableofmodules for a list of modules
available in SER distribution.
3. About iptel.org
See http://www.iptel.org/ser_history for the story of SER and iptel.org.
4. Obtaining Help
We offer best-effort free support for ser. "best-effort" means
that we try to solve your problems via email as soon as we can,
subject to available manpower.
To receive feedback to your inquiries, we recommend you to subscribe to
the serusers mailing list and post your queries there. This mailing list
is set up for mutual help by the community of ser users and developers.
To participate in the mailing list, subscribe at the following web
Send your questions to
5. More Information
Most up-to-date information is always available at our website,
Particularly, it includes:
o administrator's guide
o installation guidelines (INSTALL)
o download links
o list of known issues (ISSUES)