Deck 9: Spanning Tree Protocol Concepts

Question 1

What is one way in which STP protects a redundant Ethernet network?

A) Protects against frames looping the Layer 2 domains
B) Reduces collision domain size
C) Identifies and deletes invalid MAC to IP address mapping
D) Makes sure DTP VLANs do not have frame collisions

Answer 1

Protects against frames looping the Layer 2 domains

Question 2

How is a root bridge/switch determined?

A) All the switches in the internetwork send out hello BPDUs, and the switch that has the aggregate least number of hops to all the other switches becomes the root.
B) All the switches send out hello BPDUs, and the switch with the lowest bridge ID becomes the root.
C) All the switches send out hello BPDUs, and the switch with the highest bridge ID becomes the root.
D) The switches send out hello BPDUs, and the switch with the most direct connected switches becomes the root.
E) The core network switch becomes the root.

Answer 2

All the switches send out hello BPDUs, and the switch with the lowest bridge ID becomes the root.

Question 3

Which are true statements about STP PortFast mode?

A) The port bypasses the normal STP startup process and enters forwarding mode immediately.
B) Special BPDUs are generated to notify the other switches that the port is an access port and any switches connected to it should cause the port to be disabled.
C) It should be used on all switch uplink ports to speed convergence in case of a network failure.
D) It starts the generation of STP TCN BPDU generation in port up/down conditions.

Answer 3

The port bypasses the normal STP startup process and enters forwarding mode immediately.

Question 4

In what STP state does a port drop all received user traffic and not transmit user traffic but still listen for updated BPDUs?

A) Dropping
B) Listening
C) Blocking
D) Learning

Question 5

Switch forwarding logic dictates that a switch flood broadcasts out all switchports that are in the same ________, except the switchport in which the frame arrived.

A) Area
B) Management domain
C) Process
D) VLAN

Question 6

The only switch on a LAN that has all designated interfaces is the ________ switch.

A) Root
B) Main
C) Primary
D) Forwarding

Question 7

The switch that has the lowest STP cost will become the ________ switch for a specific segment.

A) Root
B) Designated
C) Primary
D) Forwarding

Question 8

What is the name of the field in the STP hello BPDU that contains the bridge ID of the switch that the sender of the BPDU believes is the root switch?

A) Designated bridge ID
B) STP primary ID
C) Root bridge ID
D) STP core ID

Question 9

The STP root switch is the switch with the lowest numeric value for the ________.

A) Cost
B) Primary ID
C) Router ID
D) Bridge ID

Question 10

A switch's ________ port is its interface through which it has the least STP cost to reach the root switch.

A) Root
B) Designated
C) Forwarding
D) Learning

Question 11

Refer to the figure. Based on the STP port costs shown, which of S4's interfaces will become the root port?

A) 2
B) 3
C) 1
D) None

Question 12

Refer to the figure. Based on the STP port costs shown, which of S3's interfaces will become the root port?

A) 1
B) 3
C) 2
D) None

Question 13

What is the default IEEE STP port cost for a 100 Mbps Ethernet interface?

A) 10
B) 100
C) 4
D) 19

Question 14

What is the default IEEE STP port cost for a 10 Gbps Ethernet interface?

A) 2
B) 1
C) 4
D) 10

Question 15

What default STP timer length is used for both the listening and learning states?

A) 5 seconds
B) 20 seconds
C) 15 seconds
D) 2 seconds

Question 16

________ combines multiple parallel segments of equal speed between the same pair of switches.

A) LACP
B) Load balancing
C) STP
D) EtherChannel

Question 17

The ________ feature enables a switch to transition a switchport from blocking to forwarding state quickly by bypassing the listening and learning states.

A) PortFast
B) BPDU Guard
C) FastPass
D) Host mode