Source note · Early media and ringback behavior

For Teams Direct Routing, an SBC that follows the RFC 3960 policy would play local ringing after the 180 and switch to media from the SDP candidates once the 183 arrives and media flows.

inferred · Checked 2026-09-24

Vendor: Microsoft
Product: Teams Phone Direct Routing
Subsystem: SIP proxy inbound call dialog
Deployment: multi-tenant
Region: not restricted
Release range: current as of 2026-09-24
Status: inferred
Checked: 2026-09-24

Sources

Teams Phone System Direct Routing: SIP protocol — Microsoft · tier 2 current vendor documentation · Non-media bypass flow (180 and 183 handling), read with RFC 3960 Section 3.2

Cite this note

APA

WarmTransfer. (2026, September 24). Early media and ringback behavior: source note early-media-ringback-teams-sbc-policy-inference. WarmTransfer. https://warmtransfer.net/knowledge/claims/early-media-ringback-teams-sbc-policy-inference

BibTeX

@misc{warmtransfer-claim-early-media-ringback-teams-sbc-policy-inference,
  title  = {Early media and ringback behavior: source note early-media-ringback-teams-sbc-policy-inference},
  author = {{WarmTransfer}},
  year   = {2026},
  url    = {https://warmtransfer.net/knowledge/claims/early-media-ringback-teams-sbc-policy-inference},
  note   = {Source note early-media-ringback-teams-sbc-policy-inference, checked 2026-09-24}
}

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