Source note · SIP 503 and trunk out-of-service failures
Direct Routing treats an SBC as healthy if it has sent SIP OPTIONS within the last three minutes, against an expected one-minute interval.
Checked 2026-09-25
If options were sent during the last three minutes, the SBC is considered healthy.
- Vendor
- Microsoft
- Product
- Teams Phone Direct Routing
- Subsystem
- SBC health monitoring
- Deployment
- multi-tenant
- Region
- not restricted
- Release range
- current as of 2026-09-25
- Checked
- 2026-09-25
Sources
- Monitor Direct Routing — Microsoft · tier 2 current vendor documentation · Section 'Monitoring availability of Session Border Controllers using Session Initiation Protocol (SIP) options messages'
Cite this note
APA
WarmTransfer. (2026, September 25). SIP 503 and trunk out-of-service failures: source note sip-503-trunk-failures-dr-options-health-window. WarmTransfer. https://warmtransfer.net/knowledge/claims/sip-503-trunk-failures-dr-options-health-window
BibTeX
@misc{warmtransfer-claim-sip-503-trunk-failures-dr-options-health-window,
title = {SIP 503 and trunk out-of-service failures: source note sip-503-trunk-failures-dr-options-health-window},
author = {{WarmTransfer}},
year = {2026},
url = {https://warmtransfer.net/knowledge/claims/sip-503-trunk-failures-dr-options-health-window},
note = {Source note sip-503-trunk-failures-dr-options-health-window, checked 2026-09-25}
}