In this illustration, three routers are arranged in a triangle-at the left point of the triangle is router X, at the top is router Y, and on the right is router Z. X and Y are connected by a line labeled 4, Y and Z are connected by a line labeled 1, and Z and X are connected by a line labeled 50.

In figure 5.7(a) a blue line points from the number 4 to a number 1. In figure 5.7(b), a blue line points from the number 4 to a number 60.