Can PostGIS do Route optimization / shortest pass

Is there route optimization functionality in PostGIS? Given starting point and end point (assume there is street center line in database), does PostGIS have any existing function which can calculate shortest route (in time or distance)? If it does, what kind of information I can get from it? Such as total route time, route length, and route description, points/polylines which make the route?

Thanks in advance for any help.
Fay