Switch1 Becomes Root

Each bridge calculates all the paths from itself to the root. It then selects the shortest path. The next-hop bridge toward the root is the designated bridge. The port that leads to the designated bridge is selected to be the root port because it is closest from this bridge to the root bridge. The metric that STP uses for this determination is cost, which is based on the interface speed. Table 1-8 compares bandwidth to STP interface costs.