early offer sip fast start h323 mtp - MRGL of SIP Trunk or H323 GW?

[Michael San Marco]

Hi everyone, I have a quick question that I am unable to find the answer to via google.

I have the following setup

Remote VGW --h323--> CUCM --sip--> CUBE --sip--> PSTN

I have "Early Offer support for voice and video calls (insert MTP if needed)" on the sip profile for the sip trunk to the CUBE, and "inbound fast start" enabled for the H323 VGW. This setup solved an issue with ringback on outbound calls.

My question is when MTP is invoked, which MRGL is used to select the MTP resource? The MRGL on the SIP Trunk or the MRGL on the H323 VGW?

[Tony Cilli Jr]

So is the call coming from a device on the Remote GW that has an H323 trunk to CUCM? Inbound fast start calls to CUCM do not require an MTP, only outbound faststart connections do. So based on your call flow above - a call going out the SIP trunk to your CUBE would require an MTP if doing early-offer.