Source note · SDP offer answer and codec negotiation
A codec referenced with a specific payload type number in the offer should carry the same number in the answer, and even then the answer must contain rtpmap attributes for dynamic payload types and should contain them for static ones.
Checked 2026-09-15
Even if the same payload type number is used, the answer MUST contain rtpmap attributes to define the payload type mappings for dynamic payload types, and SHOULD contain mappings for static payload types.
- Vendor
- IETF
- Product
- SIP
- Subsystem
- SDP offer/answer
- Deployment
- not restricted
- Region
- not restricted
- Release range
- RFC 3264
- Checked
- 2026-09-15
Sources
- RFC 3264 — An Offer/Answer Model with the Session Description Protocol (SDP) — IETF / RFC Editor · tier 1 standards and regulators · RFC 3264 section 6.1 Unicast Streams
Cite this note
APA
WarmTransfer. (2026, September 15). SDP offer answer and codec negotiation: source note sdp-oa-payload-numbers-should-be-reused. WarmTransfer. https://warmtransfer.net/knowledge/claims/sdp-oa-payload-numbers-should-be-reused
BibTeX
@misc{warmtransfer-claim-sdp-oa-payload-numbers-should-be-reused,
title = {SDP offer answer and codec negotiation: source note sdp-oa-payload-numbers-should-be-reused},
author = {{WarmTransfer}},
year = {2026},
url = {https://warmtransfer.net/knowledge/claims/sdp-oa-payload-numbers-should-be-reused},
note = {Source note sdp-oa-payload-numbers-should-be-reused, checked 2026-09-15}
}