Offer, answer, and SDP

RFC 3264 is titled An Offer/Answer Model with the Session Description Protocol (SDP).
RFC 8866 defines SDP for describing multimedia sessions for announcement, invitation, and other initiation. The page says this document obsoletes RFC 4566.
Wikipedia's SIP article says media type and parameter negotiation and media setup are performed with SDP.
RFC 3966 specifies the tel URI for telephone numbers.
RFC 4733 is the RTP payload for DTMF digits, telephony tones, and telephony signals, and it obsoletes RFC 2833.

These are study notes, not vendor documentation and not legal advice. learning-only student project. https://cyphermonkeylabs.com/#contact https://github.com/CypherMonkeyLabs https://linktr.ee/cypherMonkey

Sources and go deeper

Opened 2026-10. A row marked confirm has no link, because that page was not verified.

RFC. RFC 3264, offer/answer with SDP last checked 2026-10
RFC. RFC 8866, SDP last checked 2026-10
Wikipedia. Session Initiation Protocol last checked 2026-10
RFC. RFC 3966, the tel URI last checked 2026-10
RFC. RFC 4733, RTP payload for DTMF last checked 2026-10
Confirm. A codec price list. confirm. None of these RFCs is a tariff. last checked 2026-10