If you're playing the beta for Star Wars Battlefront, you may have encountered some problems while playing as the Rebel Alliance during the Walker Assault mission, which takes place in the Battle of Hoth.
The Rebels regularly find themselves knee deep in Bantha fodder every time the AT-ATs and the rest of the Imperial forces converge on their base.
The objective of the mission in Walker Assault is to prevent the AT-ATs from reaching their destination at the end of the map. In order to destroy the walkers, the Rebels must capture two uplink points during each phase to lower their shields and do damage to them. When their shields are down, every player must focus their fire on one of the two AT-ATs.
YouTuber BattlefrontUpdates has put together a video showing how to make that easy, with the secret being the use of Orbital Strikes, a power-up that players can find on the battlefield. It's difficult to find, and the spawns are random. The player says that he and a friend spent most of the mission looking for it and trying to survive once they found it.
Using an Orbital Strike on the AT-AT is worth it, because it takes its health down by up to 70%, depending on how well you aim it. You won't be able to do that much damage with air support or ground fire within a comparable amount of time.
Through this effort, his team was able to take down one of the AT-ATs within the first phase.
Given how powerful the Orbital Strike power-up is when used on a walker, there's a good chance that that it'll be rebalanced before the game's release.
Additionally, it's recommended that you carry an Ion Grenade in your hand to turn the smaller AT-ST walkers into scrap metal. Firing on them with regular blaster fire doesn't do much damage.
As the YouTuber notes in the video, looking for an Orbital Strike is not the most fun way to play Battlefront, because you'll be spending most of your time avoiding enemies, but it'll guarantee you a win even if you manage to get one strike off.