At the top of this figure, we see a Visitor Location Register. A blue arrow descends from above it, and points into it. Below the VLR are two base stations positioned as points on a triangle. The left point is labeled "Old BS" and the right point is labeled "New BS." Between them is a mobile user depicted as a car. A dashed blue line extends from the VLR to the old BS and into the mobile user. A solid blue line extends from the VLR to the new BS and into the mobile user.