Spanning Tree Protocol - Networking MCQ Questions and answers

1

What is the purpose of Spanning Tree Protocol in a switched LAN?

A) To provide a mechanism for network monitoring in switched environments B) To prevent routing loops in networks with redundant paths C) To prevent switching loops in networks with redundant switched paths D) To manage the VLAN database across multiple switches E) To create collision domains

Discuss

Answer & Solution

Answer: Option C

Solution:

The Spanning Tree Protocol (STP) was designed to stop layer 2 loops. All Cisco switches have the STP on by default.

2

Which statement describes a spanning-tree network that has converged?

A) All switch and bridge ports are in the forwarding state. B) All switch and bridge ports are assigned as either root or designated ports. C) All switch and bridge ports are in either the forwarding or blocking state. D) All switch and bridge ports are either blocking or looping.

Discuss

Answer & Solution

Answer: Option C

Solution:

Convergence occurs when all ports on bridges and switches have transitioned to either the forwarding or blocking states. No data is forwarded until convergence is complete. Before data can be forwarded again, all devices must be updated.

3

What does a switch do when a frame is received on an interface and the destination hardware address is unknown or not in the filter table?

A) Forwards the switch to the first available link B) Drops the frame C) Floods the network with the frame looking for the device D) Sends back a message to the originating station asking for a name resolution

Discuss

Answer & Solution

Answer: Option C

Solution:

Switches flood all frames that have an unknown destination address. If a device answers the frame, the switch will update the MAC address table to reflect the location of the device.

4

In which circumstance are multiple copies of the same unicast frame likely to be transmitted in a switched LAN?

A) During high-traffic periods B) After broken links are reestablished C) When upper-layer protocols require high reliability D) In an improperly implemented redundant topology

Discuss

Answer & Solution

Answer: Option D

Solution:

If the Spanning Tree Protocol is not running on your switches and you connect them together with redundant links, you will have broadcast storms and multiple frame copies.

5

If you want to disable STP on a port connected to a server, which command would you use?

A) disable spanning-tree B) spanning-tree off C) spanning-tree security D) spanning-tree portfast

Discuss

Answer & Solution

Answer: Option D

Solution:

If you have a server or other devices connected into your switch that you're totally sure won't create a switching loop if STP is disabled, you can use something called portfast on these ports. Using it means the port won't spend the usual 50 seconds to come up while STP is converging.

6

Which of the following statement is true?

A) A switch creates a single collision domain and a single broadcast domain. A router creates a single collision domain. B) A switch creates separate collision domains but one broadcast domain. A router provides a separate broadcast domain. C) A switch creates a single collision domain and separate broadcast domains. A router provides a separate broadcast domain as well. D) A switch creates separate collision domains and separate broadcast domains. A router provides separate collision domains.

Discuss

Answer & Solution

Answer: Option B

Solution:

Switches break up collision domains, and routers break up broadcast domains.

7

You have two switches connected together with two crossover cables for redundancy, and STP is disabled. Which of the following will happen between the switches?

A) The routing tables on the switches will not update. B) The MAC forward/filter table will not update on the switch. C) Broadcast storms will occur on the switched network. D) The switches will automatically load-balance between the two links.

Discuss

Answer & Solution

Answer: Option C

Solution:

If spanning tree is disabled on a switch and you have redundant links to another switch, broadcast storms will occur, among other possible problems.

8

Layer 2 switching provides which of the following?
1. Hardware-based bridging (ASIC)
2. Wire speed
3. Low latency
4. Low cost

A) 1 and 3 B) 2 and 4 C) 1, 2 and 4 D) All of the above

Discuss

Answer & Solution

Answer: Option D

Solution:

Switches, unlike bridges, are hardware based. Cisco says its switches are wire speed and provide low latency, and I guess they are low cost compared to their prices in the 1990s.

9

Your switch has a port status LED that is alternating between green and amber. What could this indicate?

A) The port is experiencing errors. B) The port is shut down. C) The port is in STP blocking mode. D) Nothing; this is normal.

Discuss

Answer & Solution

Answer: Option A

Solution:

When you connect to a switch port, at first the link lights are orange/amber, and then they turn green, indicating normal operation. If the link light is blinking, you have a problem.

10

You want to run the new 802.1w on your switches. Which of the following would enable this protocol?

A) Switch(config)# spanning-tree mode rapid-pvst B) Switch# spanning-tree mode rapid-pvst C) Switch(config)# spanning-tree mode 802.1w D) Switch# spanning-tree mode 802.1w

Discuss

Answer & Solution

Answer: Option A

Solution:

802.1w is the also called Rapid Spanning Tree Protocol. It is not enabled by default on Cisco switches, but it is a better STP to run since it has all the fixes that the Cisco extensions provide with 802.1d.

Spanning Tree Protocol - Networking MCQ Questions and answers | Technical Aptitude