When the INVITE contained no offer and a reliable provisional response is the first reliable message sent back to the UAC, the offer must appear in that reliable provisional response.

Checked 2026-09-25

If a reliable provisional response is the first reliable message sent back to the UAC, and the INVITE did not contain an offer, one MUST appear in that reliable provisional response.
Vendor
IETF
Product
SIP
Subsystem
offer-answer
Deployment
any
Region
not restricted
Release range
RFC 3262
Checked
2026-09-25

Sources

Cite this note

APA

WarmTransfer. (2026, September 25). SIP early offer and delayed offer: source note sip-early-delayed-offer-rfc3262-offer-in-reliable-1xx. WarmTransfer. https://warmtransfer.net/knowledge/claims/sip-early-delayed-offer-rfc3262-offer-in-reliable-1xx

BibTeX

@misc{warmtransfer-claim-sip-early-delayed-offer-rfc3262-offer-in-reliable-1xx,
  title  = {SIP early offer and delayed offer: source note sip-early-delayed-offer-rfc3262-offer-in-reliable-1xx},
  author = {{WarmTransfer}},
  year   = {2026},
  url    = {https://warmtransfer.net/knowledge/claims/sip-early-delayed-offer-rfc3262-offer-in-reliable-1xx},
  note   = {Source note sip-early-delayed-offer-rfc3262-offer-in-reliable-1xx, checked 2026-09-25}
}

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