During a recent session of Elder Scrolls Online, I logged into Cyrodiil to find a battle going on near Chalmans Keep. When there is a fight, an indicator will appear on the map. I wish I had gotten a screenshot of it to show you. I'm also not really sure what size of fight is needed to show up on the map.
Anyways, I saw the fight and transported to the keep directly. Luckily the fight was near the keep, not at it. If the keep is under siege (defined by attacking the door/walls for some percentage) you cannot transport to it. So I was able to get to the fight quickly.
As usual, it was the Aldmeri Dominion causing trouble. There was some back and forth, but the AD kept coming. That indicated there was probably a Forward Camp deployed nearby (which lets them respawn at its location). Eventually we took the fight to the camp and destroyed it. Since we had some momentum, we decided to try and take the nearby Outpost. This proved to be a bad decision as the AD were able to regroup faster than we thought.
They started to siege the keep, thanks to some already weakened fortifications. Our defense was spread out and not organized, allowing them to breach both the outer and inner walls. In the end, we were defeated and the keep was taken by the AD.