A customer wants to upgrade their current S8720 Communication Manager 4 (CM) system. They have 2200 users, and a mixture of analog, DCP and IP telephones at their main location. They have six branches with
200-300 stations each served with G700 gateways, each containing an LSP. They want to gain the cost benefits of SIP trunking, and are reluctant to change out the user endpoints, but they want to experiment with a few SIP telephones for some of their remote agents. Survivability and resiliency are essential requirements.
Which elements are required for the solution?