Incorrect PSTN USAGE processing
We have a Teams tenant with the Direct Routing for PSTN calls. In our case we have the following requirements:
1. Calls to country X (e.g. USA - "+1") should go through the SBC 1. Calls to ALL international calls should go through SBC2.
In your article https://docs.microsoft.com/en-us/microsoftteams/direct-routing-voice-routing it is written "The order of PSTN usages in voice routing policies is critical. The usages are applied in order, and if a match is found in the first usage, then other usages are never evaluated."
Based on this it was created 1 Calling Policy with 2 PSTN Usage records (PSTN1 and PSTN2). Each PSTN Usage record has one route ONLY:
PSTN1 -> "+1..." -> SBC1
PSTN2 -> "+...." -> SBC2
BUT we have the situation, when SBC1 is not operate by any reason calls to +1... start going through SBC2, though it shouldn't according to the article.