Source note · Call transfer semantics REFER and Replaces
If a user agent cannot accept a replacing INVITE, for example because it cannot establish required quality of service or keying or has incompatible media, it must return an appropriate error response and must leave the matched dialog unchanged.
Checked 2026-09-16
If the UA cannot accept the new INVITE (for example: it cannot establish required QoS or keying, or it has incompatible media), the UA MUST return an appropriate error response and MUST leave the matched dialog unchanged.
- 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, paragraph following the authorisation rules
Cite this note
APA
WarmTransfer. (2026, September 16). Call transfer semantics REFER and Replaces: source note xfersem-replaces-failure-leaves-the-dialog-alone. WarmTransfer. https://warmtransfer.net/knowledge/claims/xfersem-replaces-failure-leaves-the-dialog-alone
BibTeX
@misc{warmtransfer-claim-xfersem-replaces-failure-leaves-the-dialog-alone,
title = {Call transfer semantics REFER and Replaces: source note xfersem-replaces-failure-leaves-the-dialog-alone},
author = {{WarmTransfer}},
year = {2026},
url = {https://warmtransfer.net/knowledge/claims/xfersem-replaces-failure-leaves-the-dialog-alone},
note = {Source note xfersem-replaces-failure-leaves-the-dialog-alone, checked 2026-09-16}
}