I would like to set up video conferencing for our company. Ideally we are looking for the ability for internal users to use CUVA with their IP Phones (which they can currently do), with the ability for other companies to also connect - I'm guessing through a gateway device. Multiparty conferences are required. We also have a few Tandberg H.323 devices in meeting rooms which would be good to be included. What would be required for this setup? Is a Cisco Unified Videoconferencing 3515 Multipoint Control Unit (MCU) all that is required or is there additional requirements? Your thoughts, etc would be appreciated.