Because mobility is the backbone of a mobile UC deployment, the solution should enable communications anywhere and everywhere. Mobile UC should support full UC on a Wi-Fi or cellular network with the ability to roam between them to extend UC capabilities beyond the office and corporate campus. While roaming is key, a mobile UC deployment also should be able to operate in just Wi-Fi and just cellular environments if necessary. A mobile UC solution should fully operate within a company on the WLAN without the need of a calling plan to be purchased from the carrier in situations where cellular coverage is not needed. Conversely, if a Wi-Fi network is not needed, a mobile UC solution can work solely on the cellular network, eliminating the need to purchase more expensive dual-mode smartphones instead of single-mode devices.