iptel.org SIP Express Router (ser)

I.   About SIP Express Router (SER)
II.  Feature List
III. About iptel.org
IV.  Obtaining Help
V.   More Information

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 

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 

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 example.

II. 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
occur quickly.

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.

III. About iptel.org

See http://www.iptel.org/ser_history for the story of SER and iptel.org.

IV. 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 address: 
Send your questions to 

V. More Information

Most up-to-date information is always available at our website,

Particularly, it includes:
- administrator's guide
- installation guidelines (INSTALL)
- download links
- list of known issues (ISSUES)
- etc.