Technology - IP Techniques 9 - VoIP Protocols

Synopsis

The major open standards and proprietary protocols used for VoIP signalling and carriage of audio sessions are discussed in this report. These include RTP (Real Time Protocol), RTCP (Real Time Control Protocol), SIP (Session Initiation Protocol), Session Description Protocol (SDP), H.323, the Asterisk IAX2 protocol, XMPP, Jabber, Jingle and Skype. The report also discusses SIP and H.323 servers and NAT traversal techniques.

Table of Contents

• 1. Synopsis
• 2. Real Time Protocol (RTP)
• 3. Real Time Control Protocol (RTCP)
  • 3.1 RTCP XR
• 4. RTP profiles
• 5. H.323
  • 5.1 Gatekeepers
  • 5.2 NAT Traversal
• 6. Session Initiation Protocol (SIP)
  • 6.1 HTTP-like protocol
  • 6.2 Session Description Protocol (SDP)
  • 6.3 SIP-T
  • 6.4 SIP User Agent entities
  • 6.5 SIP servers
  • 6.6 Back-to-back User Agent (B2BUA)
  • 6.7 RTP proxy
  • 6.8 SIP spam
• 7. NAT traversal for SIP and RTP
• 8. Inter-Exchange Protocol 2 (IAX2)
  • 8.1 Trunking
• 9. XMPP, Jabber and Jingle
• 10. Skype
  • 10.1 Distributed architecture
  • 10.2 Criticism
• 11. Related reports