Music on Hold in Teams & 4 seconds until Hold is in place for caller

VickiFHL 
We are still seeing on hold delays of 3-10 seconds for Teams Direct Routing calls to individual users.

I have also been talking to our SBC support about the transfer silence issue. They have advised that some Telcos actually inject their own MoH when Teams sends a re-invite after the user presses "Transfer" in the Teams client. The 2 largest Telcos in Australia (Telstra and Optus) do not inject their own MoH for re-invites they receive that have a=inactive or a=sendonly in the SDP. For these carriers and many others, you need the SBC to intercept these re-invites and inject a MoH audio stream on behalf of the Teams user.

If injecting your own MoH at the SBC you may have an issue for blind transfers. Blind transfers start with a re-invite from Teams on first "transfer" button press, but then after you enter the phone number and press "transfer" a second time to complete the transfer, Teams sends a refer with no SDP to notify the SBC that a=sendrecv now. Could be that some SBCs are able to deal with this however.

It would be good if Teams actually acted more like a PBX and did this stuff on its own.