Your network consists of an Active Directory forest that contains two sites named Site1 and Site2. From the Internet, users can only access servers in Site1. You have an Exchange Server 2007…

Your network consists of an Active Directory forest that contains two sites named Site1 and Site2. From the Internet, users can only access servers in Site1. You have an Exchange Server 2007 organization. Each site contains servers that run the Client Access server role, the Mailbox server role, and the Hub Transport server role. You plan to transition the organization to Exchange Server 2010. You need to recommend the server role that you must transition first to Exchange Server 2010. Your solution must provide the least amount of downtime for users in the organization. Which servers should you transition first?