Where Does a Phone Register over Mobile and Remote Access? | Cisco Exam CLCOR

B.

When a phone is registered over Mobile and Remote Access (MRA), it registers with the Expressway-E server.

MRA allows remote users to securely access their corporate Cisco Unified Communications Manager (CUCM) environment from anywhere, using any device, without requiring a VPN connection. Expressway-E is the server that resides in the DMZ and provides secure traversal between the public Internet and the corporate network. It allows external users to securely connect to internal services such as CUCM, Cisco Unity Connection, and other collaboration applications.

The process of MRA registration involves the following steps:

1. The phone sends a registration request to the Expressway-C server, which is located inside the corporate network.
2. The Expressway-C server sends the registration request to the Expressway-E server in the DMZ.
3. The Expressway-E server authenticates the user and validates the request.
4. If the authentication is successful, the Expressway-E server sends the registration request to the CUCM server.
5. The CUCM server sends a response to the Expressway-E server, which is then sent back to the phone.

Once the phone is registered, it can make and receive calls, access voicemail, and use other collaboration services provided by the CUCM environment. The registration information is stored on both the Expressway-E server and the CUCM server, allowing the phone to maintain its registration status even if one of the servers fails.

In summary, when a phone is registered over MRA, it registers with the Expressway-E server, which provides secure traversal between the public Internet and the corporate network, and allows external users to securely connect to internal collaboration services.