DIDs

To every tenant can be assigned a group of DIDs, numbers to be dialed from the outside.
Each DID can be configured to reach a certain extension or Queue or Hunt Group or IVR or any combination of the elements defined for the tenant.
The same DID cannot be assigned to more than one tenant and there is no correlation between the dialing profile assigned to a tenant, the trunk provider used and the incoming DID.
For this reason is highly important that the incoming INVITE from the trunk provider contains all the info to identify correctly the DID it is addressing to.

Due to the fact there is a lack of strong standardization among trunk providers on how to transmit the DID information, a “best guess” is used to identify the correct DID, using any of the format currently in use around the world.