Source note · SIP OPTIONS pings and trunk keepalives
Unified CM marks a trunk destination address out of service if it does not answer an OPTIONS request, answers with 503 Service Unavailable or 408 Request Timeout, or a TCP connection to it cannot be set up.
Checked 2026-09-24
A destination address is considered to be 'out of service' if it fails to respond to an OPTIONS Request, if it sends a Service Unavailable (503) response or Request Timeout (408) response, or if a TCP connection cannot be established.
- Vendor
- Cisco
- Product
- Unified Communications Manager
- Subsystem
- SIP trunk
- Deployment
- on-premises
- Region
- not restricted
- Release range
- documented for 8.6(1); later releases not verified here
- Checked
- 2026-09-24
Sources
- Cisco Unified Communications Manager Trunks (Session Management Edition deployment guide 8.6(1)) — Cisco · tier 2 current vendor documentation · section 'SIP OPTIONS Ping'
Cite this note
APA
WarmTransfer. (2026, September 24). SIP OPTIONS pings and trunk keepalives: source note sip-options-keepalive-cucm-oos-conditions. WarmTransfer. https://warmtransfer.net/knowledge/claims/sip-options-keepalive-cucm-oos-conditions
BibTeX
@misc{warmtransfer-claim-sip-options-keepalive-cucm-oos-conditions,
title = {SIP OPTIONS pings and trunk keepalives: source note sip-options-keepalive-cucm-oos-conditions},
author = {{WarmTransfer}},
year = {2026},
url = {https://warmtransfer.net/knowledge/claims/sip-options-keepalive-cucm-oos-conditions},
note = {Source note sip-options-keepalive-cucm-oos-conditions, checked 2026-09-24}
}