In this illustration, we see the same elements as in the previous figure but arranged this time in the shape of a diamond, with the VLR at the top, the old BS to the left, the new BS to the right, and the mobile user at the bottom. A blue arrow, labeled 1 and corresponding to numbered steps given in the text on page 580-1, extends from the Old BS to the MSC. A blue arrow labeled 2 extends from the MSC to the New BS. The New BS is labeled 3. A blue arrow labeled 4 extends from the New BS through the MSC and to the Old BS. A blue arrow labeled 5 extends from the Old BS to the Mobile User. A blue arrow labeled 6 extends from the Mobile User to the New BS and back again to the Mobile User. A blue arrow labeled 7 extends from the Mobile User through the New BS and to the MSC. A blue arrow labeled 8 extends from the MSC to the Old BS.