ACSP Spanning Tree Protocol (STP) 5

Question 1

In MSTP, what term describes the spanning tree instance that interconnects all MSTP regions and any 802.1D or RSTP bridges in the network?

Accepted Answer

CST

Answer

The CST (Common Spanning Tree) is the single spanning tree that connects all MST regions and legacy bridges from an external perspective.

Question 2

What determines MSTP region membership when two switches are being compared?

Accepted Answer

Configuration name, revision number, and VLAN-to-instance mapping table

Answer

Switches belong to the same MSTP region only if their configuration name, revision number, and VLAN-to-instance mapping are all identical.

Question 3

Which STP enhancement allows a switch to immediately use an alternate uplink when the primary uplink fails, without waiting for full STP convergence?

Accepted Answer

UplinkFast

Answer

UplinkFast enables access-layer switches to immediately promote an alternate root port to Forwarding when the current root port fails, bypassing Listening and Learning states.

Question 4

A port is in RSTP Discarding state and receives a superior BPDU from the designated bridge on that segment. Which role does this port take?

Accepted Answer

Alternate port

Answer

A Discarding port that receives superior BPDUs from the designated bridge on its segment becomes an Alternate port, holding a backup path to the root.

Question 5

What is the purpose of BPDU Filter when applied globally (not per-port) on an Aruba switch?

Accepted Answer

It suppresses BPDUs only on PortFast-enabled ports that have not yet received a BPDU

Answer

Global BPDU Filter suppresses BPDU transmission on PortFast-enabled ports, but if a BPDU is received on such a port, PortFast is disabled and normal STP resumes.

(ACSP) Aruba Certified Switching Professional Practice Test

(ACSP) Aruba Certified Switching Professional Practice Test

ACSP Spanning Tree Protocol (STP) 5