Direct Routing starts sending its own OPTIONS only after it receives OPTIONS from the SBC, and sends them to the SBC FQDN in the Contact header of those incoming OPTIONS.

Checked 2026-09-25

Vendor
Microsoft
Product
Teams Phone Direct Routing
Subsystem
keepalive
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-options-contact. WarmTransfer. https://warmtransfer.net/knowledge/claims/sip-trunk-carrier-turn-up-dr-options-contact

BibTeX

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

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