teams direct routing consult transfer to pstn anomalies

Occasional Contributor

Using Teams with Direct Routing via Sonus (Ribbon) SBC1000 with 8.0.2 firmware and Broadworks sip trunk.

BW user (A) to MS Teams user (B) = fine

MS Teams user consults with PSTN user (C) = fine (B on hold at this point)

MS teams user transfers after consult

Call drops to transferee (C) creating a second call from A to C rather than seemless transfer.


Appears as though the Referred-By header has no replaces parameter from MS Teams thus not able to replace an existing SIP dialog in progress.


Is this the way MS Teams invokes attended call transfer?


Seems to be an old issue from S4B days?:


Or does anyone know any other parameters that may be needed to make this work?


Can MS confirm this is how they invoke consulted transfer?


3 Replies

Hi @Michael LaMontagne 


Yes already have same interop mode set when initially provisioning the sbc thanks to that blog so can rule that out for now...



@davidm2626 this sounds similar to a Ribbon SWe Lite issue I have experienced. As far as I am aware it doesn't affect SBC1000/2000, but I don't know that for certain. Might be worth logging to Ribbon to confirm.


See this -