QUESTION 21
On an STP network, the root bridge, root port, and designated port are elected in sequence. The election rules of these ports are different. List the steps for electing the root port in sequence.


Explanation:
The sequence of steps for electing the root port in an STP (Spanning Tree Protocol) network is as follows:
* Bridge ID Comparison: The Bridge ID (BID) is compared between the bridges in the network. A smaller value indicates a higher priority, meaning the bridge with the lowest Bridge ID is elected as the root bridge.
* RPC (Root Path Cost) Comparison: The path cost to reach the root bridge is calculated. The router with the lowest Root Path Cost (RPC) to the root bridge will have a higher priority for the election of the root port.
* Peer BID Comparison: If there is a tie in the Root Path Cost, the Peer BID is compared. A smaller Peer BID indicates a higher priority. This step ensures that if two routers have the same RPC, the one with the lower Peer Bridge ID wins.
* Local BID Comparison: If there is still a tie, the Local BID is compared. A smaller Local BID indicates a higher priority. This final step ensures that the router with the lowest local identifier is selected.
* Bridge ID Comparison:The first step in electing the root port is comparing the Bridge IDs. The bridge with the lowest Bridge ID becomes the root bridge. The Bridge ID is made up of the bridge priority and MAC address. The root bridge is the center of the network for STP, and all other ports will calculate their paths based on this root.