iptel.org SIP Express Router (ser)

I.   About SIP Express Router (ser)
II.  Feature List
III. About iptel.org
IV.  Obtaining Help
V.   Contact, Licensing and 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 
services.  In this way, plug-ins such as SNMP support, RADIUS 
accounting, or SMS gateway have already been developed and are 
provided as advanced features. Other modules are underway: 
Presence server, firewall control, and more.

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

Based on the latest standards, the SIP Express Router (SER) includes 
support for registrar, proxy and redirect mode. Further it acts as 
an application server with support for CPL, instant messaging and 
presence (IM&P) including a 2G/SMS gateway, a call control policy 
language, call number translation, private dial plans and accounting, 
authorization and authentication (AAA) services. SER runs on Sun/
Solaris, PC/Linux, IPAQ/Linux platforms and supports  both IPv4 and 

Most of SER features are implemented as plug-in modules. See
README-MODULES for a description of modules available in
ser distribution.

III. About iptel.org

iptel.org is a know-how organization spun off from Germany's national 
research company FhG Fokus. One of the first SIP implementations ever, 
low-QoS enhancements, interoperability tests and VoIP-capable firewall 
control concepts are examples of well-known FhG's work.

iptel.org continues to keep this know-how leadership in SIP. 
The access rate of the company's site, a well-known source of 
technological information, is a best proof of interest. Thousands 
of hits come every day from the whole Internet.

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. If you need commercial support, 
contact info@iptel.org.

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. Contact, Licensing and More Information

For any additional information, send an inquiry to info@iptel.org. 
Licensing conditions other than GPL are available on request. 

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.