What happens to our existing phone numbers during a migration to GCC High Teams calling?

Existing phone numbers are ported to the new GCC High Teams calling environment during migration. The porting process transfers ownership of the numbers from the current carrier to the GCC High Direct Routing provider, so the organization keeps its existing numbers without interruption to service.

The voice provider manages the entire porting process, which includes submitting port requests to the current carrier, coordinating the transfer timeline, and configuring the numbers within the GCC High environment. Once porting is complete, the IT administrator assigns numbers to users and sets calling policies through the Microsoft Teams Admin Center. New numbers can also be selected through the GCC High management portal if the organization wants to add lines beyond what it currently has. A managed provider typically handles the porting alongside SBC configuration and infrastructure setup so that users experience minimal downtime during the cutover. Organizations should inventory all existing numbers, identify which ones need to move to GCC High versus which can stay on a commercial system (if using an enclave approach), and work with their provider to establish a porting schedule that avoids disruption to daily operations.