Source note · Call transfer semantics REFER and Replaces
For an attended transfer the Transferor should use the Transfer Target's Contact URI as the Refer-To URI unless that URI is suspected or known not to route outside the dialog, in which case the Target's address of record should be used, and the Transferee may retry with the Contact URI if the triggered INVITE fails on a timeout or a 403 or 404.
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 7.3, paragraphs 2 and 4
Cite this note
APA
WarmTransfer. (2026, September 16). Call transfer semantics REFER and Replaces: source note xfersem-refer-to-uses-the-contact-uri. WarmTransfer. https://warmtransfer.net/knowledge/claims/xfersem-refer-to-uses-the-contact-uri
BibTeX
@misc{warmtransfer-claim-xfersem-refer-to-uses-the-contact-uri,
title = {Call transfer semantics REFER and Replaces: source note xfersem-refer-to-uses-the-contact-uri},
author = {{WarmTransfer}},
year = {2026},
url = {https://warmtransfer.net/knowledge/claims/xfersem-refer-to-uses-the-contact-uri},
note = {Source note xfersem-refer-to-uses-the-contact-uri, checked 2026-09-16}
}