Source note · SS7 and carrier interworking concepts
The Cisco IOS 15M&T SIP guide describes adding the Reason header with the Q.850 cause to outgoing BYE and CANCEL requests and 4xx, 5xx and 6xx responses, so the original ISDN disconnect cause survives the SIP leg.
Checked 2026-09-24
- Vendor
- Cisco
- Product
- Cisco IOS voice gateway
- Subsystem
- Reason header
- Deployment
- on-premises
- Region
- not restricted
- Release range
- IOS 15M&T configuration guide updated 2014-11-25
- Checked
- 2026-09-24
Sources
- SIP Configuration Guide, Cisco IOS Release 15M&T - Configuring SIP Message Timer and Response Features — Cisco · tier 2 current vendor documentation · Reason header section of the Configuring SIP Message Timer and Response Features chapter
Cite this note
APA
WarmTransfer. (2026, September 24). SS7 and carrier interworking concepts: source note ss7-carrier-interworking-cisco-reason-header. WarmTransfer. https://warmtransfer.net/knowledge/claims/ss7-carrier-interworking-cisco-reason-header
BibTeX
@misc{warmtransfer-claim-ss7-carrier-interworking-cisco-reason-header,
title = {SS7 and carrier interworking concepts: source note ss7-carrier-interworking-cisco-reason-header},
author = {{WarmTransfer}},
year = {2026},
url = {https://warmtransfer.net/knowledge/claims/ss7-carrier-interworking-cisco-reason-header},
note = {Source note ss7-carrier-interworking-cisco-reason-header, checked 2026-09-24}
}