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Knowledge Centre > 
eu-bullet.gif1. What is VoIP?
eu-bullet.gif2. How does a VoIP call work?
eu-bullet.gif3. What are VoIP call protocols?
eu-bullet.gif4. What is H323?
eu-bullet.gif6. VoIP versus IP Telephony
eu-bullet.gif7. What are the key components of a VoIP network?
eu-bullet.gif8. What devices do we need to place a VoIP call?
eu-bullet.gif9. What are IP Phones?
eu-bullet.gif10. What is a VoIP Gateway?
eu-bullet.gif11. What is an ATA?
eu-bullet.gif12. What is a VoIP gateway? How about a gatekeeper?
eu-bullet.gif13. What is a SIP Proxy?
eu-bullet.gif14. What is a SIP trunk?
eu-bullet.gif15. What is a SIP URI?
eu-bullet.gif16. What is a CODEC?
eu-bullet.gif17. The benefits of using VoIP?
eu-bullet.gif18. How do I set up a simple VoIP network on an existing LAN?
eu-bullet.gif19. What is a DDI?
eu-bullet.gif20. What are PBXs?
eu-bullet.gif21. What functions does a PBX perform?
eu-bullet.gif22. What is an IP PBX?
eu-bullet.gif23. What does an ITSP do?
5. What is SIP?
Session Initiation Protocol (SIP) is the IETF's standard for establishing VoIP connections.  SIP is an application layer control protocol for creating, modifying and terminating sessions with one or more participants.  The architecture of SIP is similar to that of HTTP (client-server protocol).  Requests are generated by the client and sent to the server.  The server processes the requests and then sends a response to the client.  A request and the responses for that request make a transaction.

SIP is widely considered a protocol of choice for VoIP communication.