Zoom sends a SIP OPTIONS request to each configured SBC every 30 seconds and declares the trunk down after four consecutive failed keepalives, which takes 90 to 120 seconds.

Checked 2026-09-24

Zoom sends an OPTIONS request to the target IP Address/Port configured in SBC settings every 30 seconds.
Vendor
Zoom
Product
Zoom Phone; Zoom Contact Center
Subsystem
byoc-p-resilience
Deployment
hybrid
Region
not restricted
Release range
current as of 2026-09-24
Checked
2026-09-24

Sources

Cite this note

APA

WarmTransfer. (2026, September 24). Zoom Phone routing and PSTN connectivity: source note zoom-phone-routing-options-keepalive. WarmTransfer. https://warmtransfer.net/knowledge/claims/zoom-phone-routing-options-keepalive

BibTeX

@misc{warmtransfer-claim-zoom-phone-routing-options-keepalive,
  title  = {Zoom Phone routing and PSTN connectivity: source note zoom-phone-routing-options-keepalive},
  author = {{WarmTransfer}},
  year   = {2026},
  url    = {https://warmtransfer.net/knowledge/claims/zoom-phone-routing-options-keepalive},
  note   = {Source note zoom-phone-routing-options-keepalive, checked 2026-09-24}
}

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