Source note · SS7 and carrier interworking concepts
RFC 3326 allows the Reason header in any request within a dialog and in any CANCEL request, which lets a gateway pass the ISUP release cause onward in BYE or CANCEL.
Checked 2026-09-24
- Vendor
- IETF
- Product
- SIP
- Subsystem
- Reason header
- Deployment
- carrier, on-premises, multi-tenant
- Region
- not restricted
- Release range
- current as of 2026-09-24
- 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 · Section 2; Section 3.4 example of a gateway receiving ISUP REL
Cite this note
APA
WarmTransfer. (2026, September 24). SS7 and carrier interworking concepts: source note ss7-carrier-interworking-reason-in-requests. WarmTransfer. https://warmtransfer.net/knowledge/claims/ss7-carrier-interworking-reason-in-requests
BibTeX
@misc{warmtransfer-claim-ss7-carrier-interworking-reason-in-requests,
title = {SS7 and carrier interworking concepts: source note ss7-carrier-interworking-reason-in-requests},
author = {{WarmTransfer}},
year = {2026},
url = {https://warmtransfer.net/knowledge/claims/ss7-carrier-interworking-reason-in-requests},
note = {Source note ss7-carrier-interworking-reason-in-requests, checked 2026-09-24}
}