Kamailio General Information

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Configuration file architecture

File:kamailio_conf_architecture.JPG The kamailio.cfg file will be execute foe every SIP message received

Important SIP terminology for Kamailio

  • before we proceed, you should understand the following terminology: Sessions, transactions and_dialogs
  • Kamailio can operate as statefull or stateless SIP proxy:
    • The TM (transaction) module will handle the statefull state. note that SER is "transaction statefull" (INVITE to 200OK) and NOT dialog statefull(INVITE to BYE)
    • The following diagram shows the statefull proxy message proccessing


  • Strict and Loose Routing
    • Loose routing is new method that Keeps the target seperated from the route:
    • in order to support loose route use the ;lr parameter in the "Route" or "Record-Route"


  • In order to keep Kamailio in the middle you should use the record_route() function
  • Kamailio is media agnostic - means it does not change the the SDP unless it uses media proxy such as RTPProxy.
  • t_relay() will route in the context of transaction
  • onreply_route[] will handle transaction replies
  • faiure_route[] will handle transaction failures
  • if you replace t_relay() with forward() - ser will become stateless (will not follow the transaction VIA). replies wil not reach to the on_reply_route[] section.
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