If you are ranged DPS, you have one of Eve isk the most important responsibilities in offense: take out turrets. Fortress cannons are the most potent defense winter grasp Fortress has, and they will make short work of your siege vehicles even before they get to the awls. This makes it imperative to destroy the cannons, something only ranged DPS can do. Coordinate with your raid or faction to find out which side they are attacking. Destroying all the cannons on one side makes the fortress extremely vulnerable, I can't stress the importance of destroying turrets.