An access point is a location on the edge of a map where reinforcements can be supplied from adjacent battlefields. The access points are connected with supply lines.
On the Campaign map, access points are represented by the small circles surrounding a larger Map point. The supply lines are also shown as an actual line connecting two access points. Control of Access Points is determined by Skirmish battles.
Each access point has a corresponding spawn location in the Action Game. These spawn locations are labeled with '1', and usually form the beginning of a 'chain' of capture points (e.g. A1 to A4). The particular access point occupied by Assault Teams on the campaign map determines which players can spawn where in the Action Game: members of an assault team can only spawn at capture points with a "chain" of owned points connecting to their access point.
In an Assault/Defense mission, when the defending team captures an Access Point, the Assault Teams attacking from that point are no longer available. Players refer to this as them having been "pushed off the map".