Introduction to SIP

A three day class on SIP, the Session Initiation Protocol and companion protocols. This class gives you the foundation needed to work with SIP and debug SIP.


  • The history of SIP
  • Protocol constructs: Requests and responses
  • Transactions and dialogs
  • SIP addressing
  • Using DNS: Locating a SIP server
  • SIP routing
  • Proxy servers and B2B-user-agents
  • Gatewaying to the PSTN: SIP trunking
  • Debugging SIP
  • RTP – The media protocol
  • RTCP – Controlling QoS
  • Codecs for audio and video
  • SIP Presence and busy lamp fields
  • SIP call transfers
  • SIP security


  • Registering a phone to a domain
  • Watching what happens in Asterisk
  • Call routing with SIP Proxys
  • Debugging with Wireshark