Source note · Carrier escalation evidence packages

The Reason header may appear in any request within a dialog, in any CANCEL request, and in responses whose status code explicitly allows it; RFC 3326 highlights its use in BYE and CANCEL.

Checked 2026-09-24

Vendor: IETF
Product: SIP
Subsystem: Reason header
Deployment: any
Region: not restricted
Release range: RFC 3326
Checked: 2026-09-24

Sources

RFC 3326: The Reason Header Field for the Session Initiation Protocol (SIP) — IETF / RFC Editor · tier 1 standards and regulators · Sections 2 and 3

Cite this note

APA

WarmTransfer. (2026, September 24). Carrier escalation evidence packages: source note carrier-escalation-evidence-reason-header-placement. WarmTransfer. https://warmtransfer.net/knowledge/claims/carrier-escalation-evidence-reason-header-placement

BibTeX

@misc{warmtransfer-claim-carrier-escalation-evidence-reason-header-placement,
  title  = {Carrier escalation evidence packages: source note carrier-escalation-evidence-reason-header-placement},
  author = {{WarmTransfer}},
  year   = {2026},
  url    = {https://warmtransfer.net/knowledge/claims/carrier-escalation-evidence-reason-header-placement},
  note   = {Source note carrier-escalation-evidence-reason-header-placement, checked 2026-09-24}
}

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