By default Direct Routing retries an outbound call on another SBC in the voice routing policy when the first SBC returns 408, 503 or 504; the list is set with the FailoverResponseCodes parameter.

Checked 2026-09-25

Vendor
Microsoft
Product
Teams Phone Direct Routing
Subsystem
failover
Deployment
multi-tenant
Region
not restricted
Release range
current as of 2026-09-25
Checked
2026-09-25

Sources

Cite this note

APA

WarmTransfer. (2026, September 25). SIP trunk carrier turn-up and acceptance testing: source note sip-trunk-carrier-turn-up-dr-failover-codes. WarmTransfer. https://warmtransfer.net/knowledge/claims/sip-trunk-carrier-turn-up-dr-failover-codes

BibTeX

@misc{warmtransfer-claim-sip-trunk-carrier-turn-up-dr-failover-codes,
  title  = {SIP trunk carrier turn-up and acceptance testing: source note sip-trunk-carrier-turn-up-dr-failover-codes},
  author = {{WarmTransfer}},
  year   = {2026},
  url    = {https://warmtransfer.net/knowledge/claims/sip-trunk-carrier-turn-up-dr-failover-codes},
  note   = {Source note sip-trunk-carrier-turn-up-dr-failover-codes, checked 2026-09-25}
}

Read in context