An offer that arrives in a response (for example in a 2xx to a delayed-offer INVITE) cannot be rejected with 488; the UA should answer it and then start a new offer/answer exchange to fix parameters, or terminate the session.

Checked 2026-09-25

Vendor
IETF
Product
SIP
Subsystem
offer rejection
Deployment
any
Region
not restricted
Release range
RFC 6337
Checked
2026-09-25

Sources

Cite this note

APA

WarmTransfer. (2026, September 25). SIP 488 and codec negotiation failures: source note sip-488-codec-failures-offer-in-response. WarmTransfer. https://warmtransfer.net/knowledge/claims/sip-488-codec-failures-offer-in-response

BibTeX

@misc{warmtransfer-claim-sip-488-codec-failures-offer-in-response,
  title  = {SIP 488 and codec negotiation failures: source note sip-488-codec-failures-offer-in-response},
  author = {{WarmTransfer}},
  year   = {2026},
  url    = {https://warmtransfer.net/knowledge/claims/sip-488-codec-failures-offer-in-response},
  note   = {Source note sip-488-codec-failures-offer-in-response, checked 2026-09-25}
}

Read in context