In a Teams DR Carrier Tenant - can we also have users using the carrier trunk?

Question

In the configuration documentation for setting up Direct Routing for Multiple Tenants, it says that the carrier tenant (service tenant) is not for users. It only notes this in a specific table for the SBC configuration that is used for explaining the domain / sub-domain relations in carrier/customer tenants. I cannot find any other references that either confirm that the carrier tenant cannot be used for users (that belong to the carrier tenant) - nor can I find anything that says it can be used for that purpose as well.

Can anyone in the community shed some light on this? Have you tried this and it failed / or it does in fact work (for users in the carrier tenant)?

Answer 1

Hi @DavidHammel-3769

According to the Microsoft documentation, a carrier can have users using the carrier trunk in a Teams DR Carrier Tenant. This scenario is designed for Microsoft partners and/or PSTN carriers, who sell telephony services delivered to Microsoft Teams to their customers. A carrier deploys and manages an SBC in their datacenter, interconnects the SBC to multiple tenants, provides PSTN services to customers, and manages call quality end to end. To configure this scenario, a carrier needs to register a base domain name in the carrier tenant and request a wildcard certificate, and then register a subdomain for every customer, which is part of the base domain. The carrier also needs to work with a customer global administrator to add and activate the subdomain name in the customer tenant, and configure the trunk from the carrier to the customer tenant and provision users.

In the configuration documentation for setting up Direct Routing for Multiple Tenants, it says that the carrier tenant (service tenant) is not for users. It only notes this in a specific table for the SBC configuration that is used for explaining the domain / sub-domain relations in carrier/customer tenants.

The carrier tenant is not for users, but for hosting the SBC and the base domain. The carrier tenant does not have any licenses or phone numbers assigned to it, and it does not have any users that can make or receive calls. The carrier tenant is only used to register the base domain and the subdomains for each customer tenant. The customer tenants are the ones that have the users, the licenses, and the phone numbers. The customer tenants are also the ones that are configured with the trunk from the carrier to the Microsoft Phone System. The carrier tenant is essentially a service tenant that provides the connectivity and the telephony services to the customer tenants.

Hope the above information is helpful for you!

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Answer 2

Thanks for your input! The information you provided is inconclusive about the ability of the carrier tenant to be used by the users of the tenant itself. It says that the customer tenants contain the users and licenses and phonenumbers and that the carrier tenant does not - but if I, as a user of the carrier organization do have the licenses, can't I just use the carrier tenant for my calls? Or does the carrier organization require its own customer tenant besides the allready existing carrier tenant?

The reason is that I'm trying to figure out how many tenants we as a (small) carrier would need to actuallt provide derrived trunks to our customers, but also provide direct routing to our own users. Having separate tenants seems a bit unecessary...

Answer 3

Not yet - I'm now able to make outgoing calls as a user in the carrier tenant, but incoming calls all result in a 404 message. I've spoken with someone on another forum who confirms that this should be possible and we've compared configurations - but for some reason for me it's not working properly. So it's a work in progress - I'm looking for details on how Microsoft determines the destination user for incoming calls so I can better understand my issue. I know that the contact header is used for determining the correct tenant on the SIP call leg, but how it works internally is a mysterie to me. Would be very helpfull if Microsoft has some flow diagram describing the lookup process after the call comes in over SIP...