Source note · Call transfer semantics REFER and Replaces
If no final response has been generated, the user agent receiving a REFER must return a 202 Accepted before the REFER transaction expires, and if the REFER is accepted with any 2xx the recipient must create a subscription and send notifications of the status of the refer.
Checked 2026-09-16 · superseded by xfersem-202-is-deprecated-for-refer
If no final response has been generated according to the rules above, the UA MUST return a 202 Accepted response before the REFER transaction expires.
- Vendor
- IETF
- Product
- Session Initiation Protocol
- Subsystem
- REFER
- Deployment
- not restricted
- Region
- not restricted
- Release range
- Standards Track
- Checked
- 2026-09-16
Sources
- RFC 3515 — The Session Initiation Protocol (SIP) Refer Method — IETF / RFC Editor · tier 1 standards and regulators · RFC 3515 section 2.4.2, final 2 paragraphs
Cite this note
APA
WarmTransfer. (2026, September 16). Call transfer semantics REFER and Replaces: source note xfersem-refer-202-and-the-subscription. WarmTransfer. https://warmtransfer.net/knowledge/claims/xfersem-refer-202-and-the-subscription
BibTeX
@misc{warmtransfer-claim-xfersem-refer-202-and-the-subscription,
title = {Call transfer semantics REFER and Replaces: source note xfersem-refer-202-and-the-subscription},
author = {{WarmTransfer}},
year = {2026},
url = {https://warmtransfer.net/knowledge/claims/xfersem-refer-202-and-the-subscription},
note = {Source note xfersem-refer-202-and-the-subscription, checked 2026-09-16}
}