CSR1000V | CUBE | Teams Direct Routing | Long Delay responding to Refer Message

[Carl Ratcliffe]

Hi Support Community, 

I have a CSR1000V used as a dedicated SBC between Microsoft Teams and PSTN/CUCM for Direct Routing. 

Calls from PSTN/CUCM to Microsoft Teams work no issues. CUBE CSR1000V Teams Direct Routing

Calls from Microsoft Teams to CUCM work no isses. 

What I have an issue with is transfer and most of the time it will take a really long time to complete the transfer but will also often fail. The config is setup exactly as the link below and I think the REFER part is working as detailed apart from the delay experienced  and even the SIP messages show as you would expect in a REFER just with a delay. 

When we receive the REFER from Microsoft Teams then we immediately send a 202 Accepted. Its then as though the CUBE doesn't do anything for 25-30 seconds before it sends a NOTIFY followed by INVITE back to Microsoft Teams and normal flow seems to resume. Even when debugging it doesn't really seem to be doing anything apart from responding to OPTIONS. 

Anyone any ideas what could be causing this ? I even upgraded and downgraded the IOS and it made no difference. I don't know if I or the document is missing something obvious or if the delay is just because it doesn't like something in the REFER. 

I have attached a debug CCSIP messages which is started just before the transfer is requested from the Teams client. 

Direct Routing for Microsoft Phone System with Cisco Unified Border Element (CUBE) 

Thanks, Carl Ratcliffe 

[Jonas Fraga]

Hello, Carl.

I'm not seeing the attached CCSIP messages on your post.

About this integration, both Microsoft and Cisco agreed that is only intention for PSTN purposes and not officially supported for "PBX" integration even when we know that works.

Based on that I'm wondering if Both systems should support REFER exchange when we're not talking about PSTN flow and maybe one way out for this is not send REFER messages from any side of this call. CUBE and CUCM supports that which makes Microsoft Teams not aware that was a transfer, but it will happened at CUCM level, for example.

[korvanessen]

Hi Carl,

Did you get this resolved? I can see the exact same behaviour with our CSR1000V CUBE, and I can't get my head around it.

Thanks, Kor

[Carlo Poggiarelli]

Hi,

Can  you please capture a debug ccsip message output while transfer a call and, if possible, your current config.

Thanks

Regards

Carlo