The number of SIP related standards is enormous and growing. Some are useful, some are stupid, some are redundant and some never catch on. There is even an RFC to keep track of the SIP RFC's and it does a good job
A Hitchhiker's Guide to the Session Initiation Protocol (SIP)
although by its nature it was out of date as soon as it was written (for example the protocol in the document as
has since been allocated as RFC 5626) . The current state of SIP related standards is available on the
IETF SIP Working Group home status page
and a normative list of SIP related parameters; which includes things like headers, options tages etc; is available
IANA SIP Parameters
. Some good examples of SIP protocol usage are documented in
Session Initiation Protocol Service Examples
) and also at the industry sponsored portal
This project makes an attempt to implement the core
SIP: Session Initiation Protocol
standard and also a number of related standards. This page lists the SIP related standards that are relevant to the project and the implementation effort or lack thereof for each one.
- RFC 3261 SIP: Session Initiation Protocol the core SIP protocol. The project seeks to fully implement the protocol described in this document.
The implementation effort is estimated as 90% complete.
- RFC 3263 Session Initiation Protocol (SIP): Locating SIP Servers documents the mechanisms recommended to use DNS to locate SIP servers: utilises NAPTR, SRV and A records. The project seeks to fully
implement the protocol described in this document. The implementation effort is estimated as 90% complete.
- RFC 3515
The Session Initiation Protocol (SIP) Refer Method documents a SIP REFER method enhancement that's used to facilitate blind and attended transfers for SIP calls. The project aims to fully implement the protocol described in this document.
The implementation effort is estimated as 80% complete.
- RFC 3550 RTP: A Transport Protocol for Real-Time Applications documents the protocols used for transporting media payloads and for reporting quality metrics on the transmission of the media. Similarly
to SDP this project does not handle media and only a rudimentary understanding of RTP and RTCP packets is required.
The implementation effort is estimated as 40% complete.
- RFC 5626
Managing Client-Initiated Connections in the Session Initiation Protocol (SIP) documents the re-use of connections established by registrations for subsequent call requests along with some NAT keep-alive mechanisms. Equivalent but simpler procedures are
already in use by this project and other user agents, it's unlikely this standard will get much traction.
At the time of writing no effort will be made to implement the protocol in this document.