| 2119 | Key words for use in RFCs to Indicate Requirement LevelsS. Bradner | Best Current Practice | March 1997 |
| 2141 | URN SyntaxR. Moats · obsoleted by RFC 8141 | Proposed Standard | May 1997 |
| 2326 | Real Time Streaming Protocol (RTSP)H. Schulzrinne, A. Rao, R. Lanphier · obsoleted by RFC 7826 | Proposed Standard | April 1998 |
| 2434 | Guidelines for Writing an IANA Considerations Section in RFCsT. Narten, H. Alvestrand · obsoleted by RFC 5226 | Best Current Practice | October 1998 |
| 2606 | Reserved Top Level DNS NamesD. Eastlake 3rd, A. Panitz | Best Current Practice | June 1999 |
| 2648 | A URN Namespace for IETF DocumentsR. Moats | Informational | August 1999 |
| 3023 | XML Media TypesM. Murata, S. St. Laurent, D. Kohn · obsoleted by RFC 7303 | Proposed Standard | January 2001 |
| 3261 | SIP: Session Initiation ProtocolJ. Rosenberg, H. Schulzrinne, G. Camarillo, A. Johnston, J. Peterson, R. Sparks, M. Handley, E. Schooler | Proposed Standard | July 2002 |
| 3264 | An Offer/Answer Model with Session Description Protocol (SDP)J. Rosenberg, H. Schulzrinne | Proposed Standard | July 2002 |
| 3265 | Session Initiation Protocol (SIP)-Specific Event NotificationA. B. Roach · obsoleted by RFC 6665 | Proposed Standard | July 2002 |
| 3323 | A Privacy Mechanism for the Session Initiation Protocol (SIP)J. Peterson | Proposed Standard | December 2002 |
| 3326 | The Reason Header Field for the Session Initiation Protocol (SIP)H. Schulzrinne, D. Oran, G. Camarillo | Proposed Standard | December 2002 |
| 3508 | H.323 Uniform Resource Locator (URL) Scheme RegistrationO. Levin | Informational | April 2003 |
| 3550 | RTP: A Transport Protocol for Real-Time ApplicationsH. Schulzrinne, S. Casner, R. Frederick, V. Jacobson | Internet Standard | July 2003 |
| 3629 | UTF-8, a transformation format of ISO 10646F. Yergeau | Internet Standard | November 2003 |
| 3688 | The IETF XML RegistryM. Mealling | Best Current Practice | January 2004 |
| 3892 | The Session Initiation Protocol (SIP) Referred-By MechanismR. Sparks | Proposed Standard | September 2004 |
| 3966 | The tel URI for Telephone NumbersH. Schulzrinne | Proposed Standard | December 2004 |
| 4235 | An INVITE-Initiated Dialog Event Package for the Session Initiation Protocol (SIP)J. Rosenberg, H. Schulzrinne, R. Mahy, Ed. | Proposed Standard | November 2005 |
| 4353 | A Framework for Conferencing with the Session Initiation Protocol (SIP)J. Rosenberg | Informational | February 2006 |
| 4474 | Enhancements for Authenticated Identity Management in the Session Initiation Protocol (SIP)J. Peterson, C. Jennings · obsoleted by RFC 8224 | Proposed Standard | August 2006 |
| 4566 | SDP: Session Description ProtocolM. Handley, V. Jacobson, C. Perkins · obsoleted by RFC 8866 | Proposed Standard | July 2006 |
| 4574 | The Session Description Protocol (SDP) Label AttributeO. Levin, G. Camarillo | Proposed Standard | August 2006 |