Next week, on January 28-29, DICE will be migrating the Battlefield 3 console servers to "optimize our online service." The process will take approximately 8 hours and will begin on January 28 at 22:00 PST.
If you are a regular Battlefield 3 player, this shouldn't affect you at all, except for some inconvenient downtime during the maintenance. While the server migration is occurring you will be unable to play online.
Things get a little bit trickier if you are renting a console server in the "South US" region. For most players renting a server, the server migration is a completely "transparent" operation except for the planned maintenance. For those in the "South US" region, your current lease will run its full course with no change. However, after the server migration you will not be able to extend your current lease or start a new lease in the "South US" region. DICE recommends you use the "East US" or "West US" region instead.