Binary package “ser” in ubuntu oneiric

high-performance SIP server

 SER, the SIP Express Router, is a very fast and flexible server for
 SIP (the Session Initiation Protocol). It can act as a SIP
 registrar, proxy or redirect server. SER can be configured to serve
 specialized purposes such as load balancing or SIP front-end to
 application servers. Together with the RTPproxy it can act as media
 relay or Session Border Controller.
 .
 SER features complete support of RFC 3261 functionality, a variety of
 database backends, management features, load-balancing), NAT
 traversal, telephony features (LCR, speeddial), multidomain hosting,
 ENUM, presence, and more.