Domination: g_gametype 12.
In OA 0.7.6 this gametype was badly supported and therefore not available by default. The scoring system was slightly changed in 0.7.7. In recent versions, it works correctly.
Teams score by holding domination points. There can be up to 6 domination points in a map. If there are 1-3 domination points they will generate a point every two seconds. If there are 4-6 domination points they will generate 1 point every 4 seconds.
For this gametype, is advisable to set capturelimit to 500, instead of to 8, like the usual (with a very small capturelimit, a Domination match would last few seconds).
Note: as far as OA 0.8.8, there is no "callvote" option for "capturelimit". However, server admins can setup custom votes to allow players some choices.
Typically played on maps designed for Deathmatch mode (working only if the author of the map added support for this gametype). You can play it on maps like islanddm and am_underworks2.