An agent must not generate a new offer while it has an offer outstanding in either direction, and an offer arriving after one has been sent but before its answer is the condition RFC 3264 calls glare, which the higher layer protocol has to resolve.

Checked 2026-09-15

If an agent receives an offer after having sent one, but before receiving an answer to it, this is considered a "glare" condition.
Vendor
IETF
Product
SIP
Subsystem
SDP offer/answer
Deployment
not restricted
Region
not restricted
Release range
RFC 3264
Checked
2026-09-15

Sources

Cite this note

APA

WarmTransfer. (2026, September 15). SDP offer answer and codec negotiation: source note sdp-oa-one-offer-outstanding-at-a-time. WarmTransfer. https://warmtransfer.net/knowledge/claims/sdp-oa-one-offer-outstanding-at-a-time

BibTeX

@misc{warmtransfer-claim-sdp-oa-one-offer-outstanding-at-a-time,
  title  = {SDP offer answer and codec negotiation: source note sdp-oa-one-offer-outstanding-at-a-time},
  author = {{WarmTransfer}},
  year   = {2026},
  url    = {https://warmtransfer.net/knowledge/claims/sdp-oa-one-offer-outstanding-at-a-time},
  note   = {Source note sdp-oa-one-offer-outstanding-at-a-time, checked 2026-09-15}
}

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