Creating a subscription always results in an immediate NOTIFY, and the agent that issued the REFER must be prepared to receive a NOTIFY before the REFER transaction completes.

Checked 2026-09-16

Vendor
IETF
Product
Session Initiation Protocol
Subsystem
REFER
Deployment
not restricted
Region
not restricted
Release range
Standards Track
Checked
2026-09-16

Sources

Cite this note

APA

WarmTransfer. (2026, September 16). Call transfer semantics REFER and Replaces: source note xfersem-refer-immediate-notify. WarmTransfer. https://warmtransfer.net/knowledge/claims/xfersem-refer-immediate-notify

BibTeX

@misc{warmtransfer-claim-xfersem-refer-immediate-notify,
  title  = {Call transfer semantics REFER and Replaces: source note xfersem-refer-immediate-notify},
  author = {{WarmTransfer}},
  year   = {2026},
  url    = {https://warmtransfer.net/knowledge/claims/xfersem-refer-immediate-notify},
  note   = {Source note xfersem-refer-immediate-notify, checked 2026-09-16}
}

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