Which statement describes the term root guard in the operation of STP?
- It is a feature that prevents a configured port from becoming a root port.
- It is a value that decides which switch can become the root bridge.
- It is a safety mechanism that shuts down ports configured with STP portfast upon receipt of a BPDU.
- It is a feature that prevents any alternative or root ports from becoming designated ports because of a loss of BPDUs on the root port.
| Explanation & Hints:
The statement that describes the term root guard in the operation of Spanning Tree Protocol (STP) is:
Root Guard is a security feature in the STP protocol designed to maintain the intended network topology by preventing switches connected to a port where Root Guard is enabled from becoming the root bridge. This is achieved by blocking the port from becoming a root port if a superior BPDU is received on that port. The purpose of Root Guard is to enforce the position of the root bridge in the network and prevent external switches or any changes in the network from altering the STP topology. When a Root Guard enabled port receives a superior BPDU, which could potentially make it a root port, the guard puts the port into a root-inconsistent state, effectively blocking all traffic except for STP BPDUs until the superior BPDUs cease. This mechanism ensures the stability and predictability of the network’s STP topology, safeguarding against unintended root bridge changes. |