1. B3 B1 B7 B2 B5 B4 B6 Which interfaces to keep and which to ignore. Pretend that the objective is to route to root (the one with smallest ID) and use least cost with minimum ID to break ties.

2. B3 B1 B7 B2 B5 B4 B6 2 1*1* (2) B5 has a path that takes one hop to root. B3 has a path that takes 2 hops. B5 also has a path that takes 2 hops, but this doesn’t matter.

3. B3 B1 B7 B2 B5 B4 B6 2 1*1* (2) B5 has a path that takes one hop to root. B3 has a path that takes 2 hops. B5 also has a path that takes 2 hops, but this doesn’t matter.

4. B3 B1 B7 B2 B5 B4 B6 1*1* (3) 1 (2) B5 has a path with one hop. B7 has a path with 1 hop, but 5 is less than 7, so 5 gets the route.

5. B3 B1 B7 B2 B5 B4 B6 2 1

6. B3 B1 B7 B2 B5 B4 B6 2 1

7. B3 B1 B7 B2 B5 B4 B6 2 1