I have for the last 26 years been a Nortel PBX technician working on Option series and CS1000 platforms. I have been given a task of assisting in upgrading of a AVAYA G450 system with 6 cabinets. I honestly do not know the AVAYA Red product line that well to where I can give accurate info. the system currently has several hundred users with a call center application. What they would like to do is upgrade this system and install VOIP telephone sets. This facility is currently using both 1408 & 1416 digital telephone sets. I know that you will need licenses, some media gateways but what else will be needed? Any help or direction is greatly appreciated. Thank you in advance.