ACSP Spanning Tree Protocol (STP) 3

Question 1

In an Aruba switch running MSTP, which command correctly maps VLAN 10 and VLAN 20 to MST instance 1?

Accepted Answer

spanning-tree mst 1 vlan 10,20

Answer

On Aruba switches, the correct syntax to assign VLANs to an MST instance is 'spanning-tree mst vlan '.

Question 2

What happens to STP topology when two switches have the same bridge priority and the same MAC address is theoretically used?

Accepted Answer

The switch with the lower MAC address becomes root

Answer

When bridge priorities are equal, STP uses the MAC address as a tiebreaker, and the numerically lower MAC address wins the root election.

Question 3

Which STP timer controls how long a switch stores BPDU information before considering the topology stale?

Accepted Answer

Max age

Answer

Max age (default 20 seconds) is the time a switch retains BPDU information; if no BPDU is received within this period, the port information ages out.

Question 4

Which feature prevents a non-root bridge from becoming root by blocking superior BPDUs received on a designated port?

Accepted Answer

Root Guard

Answer

Root Guard places a port in root-inconsistent state if a superior BPDU is received, preventing that port from becoming the root port.

Question 5

In RSTP, what is the purpose of the Backup port role?

Accepted Answer

It provides redundancy to a segment where the switch itself is the designated bridge

Answer

An RSTP Backup port is a redundant path to a segment for which the local switch is already the designated bridge, typically seen with hubs.

(ACSP) Aruba Certified Switching Professional Practice Test