Source note · Call transfer semantics REFER and Replaces
A Replaces header field that matches no dialog, that matches more than one dialog, or that matches a dialog not created with an INVITE is answered with 481 Call/Transaction Does Not Exist, and in the multiple-match case the user agent must act as if no match was found.
Checked 2026-09-16
- Vendor
- IETF
- Product
- Session Initiation Protocol
- Subsystem
- Replaces
- Deployment
- not restricted
- Region
- not restricted
- Release range
- Standards Track
- Checked
- 2026-09-16
Sources
- RFC 3891 — The Session Initiation Protocol (SIP) "Replaces" Header — IETF / RFC Editor · tier 1 standards and regulators · RFC 3891 section 3, paragraphs 5 and 6
Cite this note
APA
WarmTransfer. (2026, September 16). Call transfer semantics REFER and Replaces: source note xfersem-replaces-481-cases. WarmTransfer. https://warmtransfer.net/knowledge/claims/xfersem-replaces-481-cases
BibTeX
@misc{warmtransfer-claim-xfersem-replaces-481-cases,
title = {Call transfer semantics REFER and Replaces: source note xfersem-replaces-481-cases},
author = {{WarmTransfer}},
year = {2026},
url = {https://warmtransfer.net/knowledge/claims/xfersem-replaces-481-cases},
note = {Source note xfersem-replaces-481-cases, checked 2026-09-16}
}