Source note · Call transfer semantics REFER and Replaces
RFC 5589 models a transfer that keeps both other parties informed as an ad hoc conference in which the Transferor acts as a focus and the Transferee and Transfer Target subscribe to its conference package, and states that this is how requirement 6 is met and that a focus can also introduce media such as simulated ringback or on-hold announcements.
Checked 2026-09-16
- Vendor
- IETF
- Product
- Session Initiation Protocol
- Subsystem
- Attended transfer
- Deployment
- not restricted
- Region
- not restricted
- Release range
- BCP 149
- Checked
- 2026-09-16
Sources
- RFC 5589 — Session Initiation Protocol (SIP) Call Control - Transfer — IETF / RFC Editor · tier 1 standards and regulators · RFC 5589 section 9 Transfer as an Ad Hoc Conference
Cite this note
APA
WarmTransfer. (2026, September 16). Call transfer semantics REFER and Replaces: source note xfersem-transfer-as-an-ad-hoc-conference. WarmTransfer. https://warmtransfer.net/knowledge/claims/xfersem-transfer-as-an-ad-hoc-conference
BibTeX
@misc{warmtransfer-claim-xfersem-transfer-as-an-ad-hoc-conference,
title = {Call transfer semantics REFER and Replaces: source note xfersem-transfer-as-an-ad-hoc-conference},
author = {{WarmTransfer}},
year = {2026},
url = {https://warmtransfer.net/knowledge/claims/xfersem-transfer-as-an-ad-hoc-conference},
note = {Source note xfersem-transfer-as-an-ad-hoc-conference, checked 2026-09-16}
}