Source note · SDP offer answer and codec negotiation
The number of media lines in a session never decreases: a new offer must carry a matching media line for each one in the previous SDP, matched by position from the top, and a removed stream keeps its slot rather than disappearing.
field report · Checked 2026-09-15
Deleted media streams from a previous SDP MUST NOT be removed in a new SDP; however, attributes for these streams need not be present.
- Vendor
- IETF
- Product
- SIP
- Subsystem
- SDP offer/answer
- Deployment
- not restricted
- Region
- not restricted
- Release range
- RFC 3264
- Status
- field report
- 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 8 Modifying the Session
Cite this note
APA
WarmTransfer. (2026, September 15). SDP offer answer and codec negotiation: source note sdp-oa-media-lines-never-decrease. WarmTransfer. https://warmtransfer.net/knowledge/claims/sdp-oa-media-lines-never-decrease
BibTeX
@misc{warmtransfer-claim-sdp-oa-media-lines-never-decrease,
title = {SDP offer answer and codec negotiation: source note sdp-oa-media-lines-never-decrease},
author = {{WarmTransfer}},
year = {2026},
url = {https://warmtransfer.net/knowledge/claims/sdp-oa-media-lines-never-decrease},
note = {Source note sdp-oa-media-lines-never-decrease, checked 2026-09-15}
}