Unified CM considers the trunk in service when at least one node gets a response other than 408 or 503 from at least one destination address.

Checked 2026-09-25

Vendor
Cisco
Product
Unified Communications Manager
Subsystem
SIP trunk OPTIONS ping
Deployment
on-premises
Region
not restricted
Release range
stated in the 8.6(1) SME design guide; later releases not verified from a fetched document
Checked
2026-09-25

Sources

Cite this note

APA

WarmTransfer. (2026, September 25). SIP 503 and trunk out-of-service failures: source note sip-503-trunk-failures-cucm-in-service. WarmTransfer. https://warmtransfer.net/knowledge/claims/sip-503-trunk-failures-cucm-in-service

BibTeX

@misc{warmtransfer-claim-sip-503-trunk-failures-cucm-in-service,
  title  = {SIP 503 and trunk out-of-service failures: source note sip-503-trunk-failures-cucm-in-service},
  author = {{WarmTransfer}},
  year   = {2026},
  url    = {https://warmtransfer.net/knowledge/claims/sip-503-trunk-failures-cucm-in-service},
  note   = {Source note sip-503-trunk-failures-cucm-in-service, checked 2026-09-25}
}

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