STP Basics and Concepts 2

Question 1

Which STP port state forwards data frames AND learns MAC addresses?

Accepted Answer

Forwarding

Answer

Only the Forwarding state both learns MAC addresses and forwards data frames across the network.

Question 2

What is the default STP bridge priority value on a Cisco switch?

Accepted Answer

32768

Answer

Cisco switches default to a bridge priority of 32768, which is the midpoint of the 0–65535 range.

Question 3

Which field in the Bridge ID is used to differentiate switches with the same base priority?

Accepted Answer

MAC address

Answer

When bridge priorities are equal, the lowest MAC address breaks the tie to elect the root bridge.

Question 4

What happens to a non-root switch port that receives a superior BPDU?

Accepted Answer

It becomes a root port

Answer

A port that receives the best BPDU from the root bridge direction becomes the root port for that switch.

Question 5

What is the STP port cost for a 1 Gbps link using the original IEEE cost values?

Accepted Answer

4

Answer

The original IEEE 802.1D cost for a 1 Gbps link is 4, based on the formula 1000/bandwidth in Mbps.

(STP) Spanning Tree Protocol Practice Test