11. Switching and Virtual LANs

Question 1

1. You want to improve network performance by increasing the bandwidth available to hosts and limiting the size of the broadcast domains. Which of the following options will achieve this goal?
   a. Managed hubs
   b. Bridges
   c. Switches
   d. Switches configured with VLANs

Answer 1

d. By creating and implementing VLANs in your switched network, you can break up broadcast domains at layer 2. For hosts on different VLANs to communicate, you must have a router or layer 3 switch.

Question 2

2. The types of ports that can be found on a switch are _____ and _____. (choose two)
   a. VLAN Trunk Protocol
   b. Access
   c. 802.1Q
   d. Trunk

Answer 2

b, d. Hosts are connected to a switch and are members of one VLAN. This is called an access port. Trunk links connect between switches and pass information about all VLANs.

Question 3

3. Which switching technology reduces the size of a broadcast domain?
   a. ISL
   b. 802.1Q
   c. VLANs
   d. STP

Answer 3

c. Virtual LANs break up broadcast domains in layer 2 switched internetworks.

Question 4

4. Which of the following are IEEE versions of STP? (choose two)
   a. 802.1X
   b. VLANs
   c. 802.1D
   d. 802.11
   e. 802.1w

Answer 4

c, e. Both 802.1D and 802.1w are IEEE STP versions, with 802.1w being the latest and greatest version.

Question 5

5. You connect a host to a switch port, but the new host cannot log into the server that is plugged into the same switch. What could the problem be? (choose two)
   a. The router is not configured for the new host.
   b. The STP configuration on the switch is not updated for the new host.
   c. The host has an invalid MAC address.
   d. The switch port the host is connected to is not configured to the correct VLAN membership.
   e. STP shut down the port.

Answer 5

d, e. The best answers are that the VLAN membership for the port is configured incorrectly and that STP shut down the port.

Question 6

6. Which of the following are benefits of VLANs? (choose three)
   a. They increase the size of collision domains.
   b. They allow logical groupings of users by function.
   c. They can enhance network security.
   d. They increase the size of broadcast domains while decreasing the number of collision domains.
   e. They simplify administration.
   f. They increase the number of broadcast domains while decreasing the size of broadcast domains.

Answer 6

b, c, f. VLANs break up broadcast domains in a switched layer 2 network, which means smaller broadcast domains. They allow configuration by logical function instead of physical location and can create some security if configured correctly.

Question 7

7. Which of the following is a layer 2 protocol used to maintain a loop-free network?
   a. VTP
   b. STP
   c. RIP
   d. CDP

Answer 7

b. The Spanning Tree Protocol is used to stop switching loops in a switched network with redundant paths.

Question 8

8. What is the result of segmenting a network with a bridge (switch)? (choose two)
   a. It increases the number of collision domains.
   b. It decreases the number of collision domains.
   c. It increases the number of broadcast domains.
   d. It decreases the number of broadcast domains.
   e. It makes smaller collision domains.
   f. It makes larger collision domains.

Answer 8

a, e. Bridges break up collision domains, which would increase the number of collision domains in a network and also make smaller collision domains.

Question 9

9. You connect your host to a switch that is running network analysis software. However, you are not seeing any packets from the server. What do you need to implement on the switch to see all the packet information?
   a. VLANs
   b. STP
   c. Port mirroring
   d. Authentication

Answer 9

c. In order to see all frames that pass through the switch and read the packets with a network analyser, you need to enable port mirroring on the port your diagnostic host is plugged into.

Question 10

10. Which of the following features of a switch will allow two switches to pass VLAN network information?
    a. PoE
    b. VLANs
    c. Trunking
    d. STP

Answer 10

c. Trunking allows switches to pass information about many or all VLANs configured on the switches.

Question 11

11. What are the distinct functions of layer 2 switching that increase available bandwidth on the network? (choose three)
    a. Address learning
    b. Routing
    c. Forwarding and filtering
    d. Creating network loops
    e. Loop avoidance
    f. IP addressing

Answer 11

a, c, e. Layer 2 features include address learning, forwarding and filtering of the network, and loop avoidance.

Question 12

12. Which of the following statements 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 separate collision domains and separate broadcast domains. A router provides separate collision domains.

Answer 12

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

Question 13

13. 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. With the exception of the source port, floods the network with the frame looking for the device.
    d. Sends back a message to the originating station asking for a name resolution.

Answer 13

c. With the exception of the source port, 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.

Question 14

14. If a switch receives a frame and the source MAC address is not in the MAC address table but the destination address is, what will the switch do with the frame?
    a. Discard it and send an error message back to the originating host
    b. Flood the network with the frame
    c. Add the source address and the port to the MAC address table and forward the frame out the destination port.
    d. Add the destination to the MAC address table and then forward the frame.

Answer 14

c. Because the source MAC address is not in the MAC address table, the switch will add the source address and the port it is connected to into the MAC address table and then forward the frame to the outgoing port.

Question 15

15. When would you configure VTP on a switch?
    a. When you have hubs connected in your network
    b. When you have redundant links between switches
    c. When you have multiple hosts in multiple VLANs and you want to share all the data between hosts without a router
    d. When you have multiple switches with multiple VLANs and you want to share the VLAN database from one switch to all the others.

Answer 15

d. Virtual Trunk Protocol (VTP) is a Cisco proprietary method of having a single VLAN database advertised to all other switches in your network. This allows for ease of VLAN management in a larger network. Option C is not a possible configuration, by the way; I made that up

Question 16

16. When is STP said to be converged on the root bridge? (choose two)
    a. When all ports are in the forwarding state
    b. When all ports are in the blocking state
    c. When all ports are in the listening state.
    d. When all ports are in the learning state

Answer 16

a, b. The sequence of steps for STP convergence is, by default, blocking, listening, learning, forwarding, disabled. When all ports are in either the blocking or forwarding state, STP is converged.

Question 17

17. In which two states is the MAC address table populated with addresses? (choose two)
    a. Blocking
    b. Listening
    c. Learning
    d. Forwarding

Answer 17

c, d. In the blocking and listening states, the MAC address table is not learning. Only in the learning and forwarding states is the MAC address table learning MAC addresses and populating the MAC address table.

Question 18

18. You have multiple departments all connected to switches, with crossover cables connecting the switches together. However, response time in the network is still very slow even though you have upgraded from hubs to switches. What technology should you implement to improve response time on the networks?
    a. STP
    b. VLANs
    c. Convergence
    d. OSPF

Answer 18

b. Switches break up collision domains by default, but the network is still one large broadcast domain. In order to break up broadcast domains in a layer 2 switched network, you need to create virtual LANs.

Question 19

19. If you are configuring voice VLANs, which of the following should you configure on the switch ports to provide a higher precedence to voice traffic over data traffic to improve sound quality?
    a. Access VLANs
    b. VTP
    c. QoS
    d. STP

Answer 19

c. If you are configuring voice VLANs, you’ll want to configure quality of service (QoS) on the switch ports to provide a higher precedence to voice traffic over data traffic to improve quality of the line.

Question 20

20. What is a disadvantage of using port spanning?
    a. It breaks up broadcast domains on all ports
    b. It can create overhead on the switch
    c. It makes the switch one large collision domain
    d. It makes the switch fast between only two ports instead of all ports.

Answer 20

b. Be careful when using port mirroring/spanning on a switch because it can cause a lot of overhead on the switch and possibly crash your network. It’s therefore a good idea to use this feature at strategic times and only for short period if possible.