Does the Dimensional Anchor cast during the calling of an outsider only prevents its escape, or would it also block the attempts to get rid of it with spells like Dismissal, Banishment and Plane Shift, cast by someone else? For example, if the would-be binder failed to bind the outsider at the first try and wants to send the outsider back before it gets another chance to free itself, can he do it?
Plane shift it definitely stops. But I think Dismissal and Banishment might work. They're abjuration and not teleportation like the other spells.
However, as a GM I would probably rule it doesn't work since it's effectively forced planar travel. And planar travel and teleportation are the things dimensional anchor is supposed to stop.