| RFC3261 | Session Initiation Protocol |
| RFC3892 | The Session Initiation Protocol (SIP) Referred-By Mechanism |
| RFC2327 | Session Description Protocol |
| RFC1889 | RTP: A Transport Protocol for Real-Time Applications |
| RFC2976 | The SIP INFO Method |
| RFC3265 | Session Initiation Protocol (SIP)-Specific Event Notification |
| RFC3515 | The Session Initiation Protocol (SIP) Refer Method |
| RFC3489 | STUN Simple Traversal of User Datagram Protocol (UDP) through Network Address Translators (NATs) |