Source note · SIP OPTIONS pings and trunk keepalives
Reachability and readiness to take calls are different things, and platforms map them differently. RFC 3261 lets a UAS answer OPTIONS with a non-200 status to show readiness, Unified CM counts only 408, 503 or no response as out of service, and Kamailio's dispatcher by default accepts only 200 OK. The same far-end reply can therefore keep a trunk up on one platform and mark it down on another.
inferred · Checked 2026-09-24
- Vendor
- multi-vendor
- Product
- SIP trunk keepalive
- Subsystem
- response interpretation
- Deployment
- any
- Region
- not restricted
- Release range
- current as of 2026-09-24
- Status
- inferred
- 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', read against rfc-3261-sip Section 11.2 and kamailio-dispatcher-module-stable parameter ds_ping_reply_codes
Cite this note
APA
WarmTransfer. (2026, September 24). SIP OPTIONS pings and trunk keepalives: source note sip-options-keepalive-reachable-vs-ready. WarmTransfer. https://warmtransfer.net/knowledge/claims/sip-options-keepalive-reachable-vs-ready
BibTeX
@misc{warmtransfer-claim-sip-options-keepalive-reachable-vs-ready,
title = {SIP OPTIONS pings and trunk keepalives: source note sip-options-keepalive-reachable-vs-ready},
author = {{WarmTransfer}},
year = {2026},
url = {https://warmtransfer.net/knowledge/claims/sip-options-keepalive-reachable-vs-ready},
note = {Source note sip-options-keepalive-reachable-vs-ready, checked 2026-09-24}
}