Under what circumstances is the root port selected, and the port ID is compared when specifying the port?

1. When selecting the root port, when the port-to-root bridge overhead value and the peer bridge ID are all the same, you need to compare the peer port ID size, and the small one is preferred. 2. When selecting the designated port, when the port-to-root bridge overhead value and the local bridge ID are all the same, you need to compare the local port ID size, and the small one is preferred.