Source note · SS7 and carrier interworking concepts
RFC 3398 maps SIP 503 Service Unavailable to ISUP cause value 38 (network out of order).
Checked 2026-09-24
- Vendor
- IETF
- Product
- SIP-ISUP gateways
- Subsystem
- SIP-to-ISUP cause mapping
- Deployment
- carrier, on-premises
- Region
- not restricted
- Release range
- current as of 2026-09-24
- Checked
- 2026-09-24
Sources
- RFC 3398: Integrated Services Digital Network (ISDN) User Part (ISUP) to Session Initiation Protocol (SIP) Mapping — IETF / RFC Editor · tier 1 standards and regulators · Section 8.2.6.1 SIP Status Code to ISDN Cause Code Mapping, table
Cite this note
APA
WarmTransfer. (2026, September 24). SS7 and carrier interworking concepts: source note ss7-carrier-interworking-sip503-to-cause38. WarmTransfer. https://warmtransfer.net/knowledge/claims/ss7-carrier-interworking-sip503-to-cause38
BibTeX
@misc{warmtransfer-claim-ss7-carrier-interworking-sip503-to-cause38,
title = {SS7 and carrier interworking concepts: source note ss7-carrier-interworking-sip503-to-cause38},
author = {{WarmTransfer}},
year = {2026},
url = {https://warmtransfer.net/knowledge/claims/ss7-carrier-interworking-sip503-to-cause38},
note = {Source note ss7-carrier-interworking-sip503-to-cause38, checked 2026-09-24}
}