CCNA3Chapter 6 Practice Test Answers

What is the problem with the network in the diagram?

  • It is not possible for a router to have four FastEthernet ports.
  • The VLANs will not be able to communicate with each other.
  • The router is not needed because these VLANs can communicate through the switch.
  • This design will not scale well if more VLANs are added.

Another VLAN is added to the network shown above, but the router does not have a spare FastEthernet port. What would be the most economical solution?

  • Buy an extra module for the router to provide more FastEthernet ports.
  • Connect an extra router, link the two routers together and enable a routing protocol between them.
  • Configure a trunk link on the switch and subinterfaces on one of the router ports.
  • Use a cheap hub to connect all the VLANs to the same router interface.

A trunk link between a router and a switch is carrying traffic for six VLANs. What is a potential problem?

  • The VLANs are sharing the link’s bandwidth and this could create a bottleneck.
  • The volume of VTP traffic on the link is likely to have an adverse effect on the network’s performance.
  • The traffic for the different VLANs is likely to be confused as all the traffic goes through the same physical router interface.
  • The maximum number of subinterfaces that can be configured on a router port is five.

A switch is configured as follows:

SW(config)#int f0/1

SW(config-if)#switchport mode access

SW(config-if)#switchport accessVLAN 3

SW(config-if)#description link to router f0/0

SW(config)#int f0/2

SW(config-if)#switchport mode access

SW(config-if)#switchport accessVLAN 3

SW(config-if)#description link to router f0/1

SW(config)#int f0/3

SW(config-if)#switchport mode access

SW(config-if)#switchport accessVLAN 3

SW(config-if)#description link to PC A

SW(config)#int f0/4

SW(config-if)#switchport mode access

SW(config-if)#switchport accessVLAN 4

SW(config-if)#description link to PC B

Why is PC A unable to ping PC B?

  • There needs to be a trunk link to the router in order for VLANs to communicate with each other.
  • The no shutdown command has not been given on the switch interfaces.
  • The router will not handle traffic to or from VLAN 4.
  • Interface f0/1 on the switch should be connected to interface f0/1 on the router.

A router is to be added to the configuration shown in the diagram above. This will allow communication between the different VLANs. How many fast ethernet ports will the router need?

  • None, serial ports must be used.
  • One, since trunking can be used.
  • Two, one connecting to each switch.
  • Three, one for each VLAN.
  • Six, one for each VLAN on each switch.

How many IP addresses must be configured on the router mentioned in the previous question?

  • None, because VLANs operate at layer two.
  • One, because only one physical ports is needed.
  • Two, one for each switch.
  • Three, one for each VLAN.
  • Six, one for each VLAN on each switch.

Switchport 0/4 is on VLAN2, port 0/6 is on VLAN3, port 0/8 is on VLAN4.

Part of the router configuration is as follows:

Router(config)#interface fastethernet 0/1.2

Router(config-subif)#encapsulation dot1q 2

Router(config-subif)#ip address 192.168.1.0 255.255.255.240

Router(config)#interface fastethernet 0/1.3

Router(config-subif)#encapsulation dot1q 3

Router(config-subif)#ip address 192.168.1.33 255.255.255.240

Router(config-subif)#interface fastethernet 0/1.4

Router(config-subif)#encapsulation dot1q 4

Router(config-subif)#ip address 192.168.1.49 255.255.255.240

Which of the following host IP addresses are suitable? (Choose 2)

  • Host A, 192.168.1.20
  • Host A, 192.168.1.32
  • Host B, 192.168.1.46
  • Host B, 192.168.1.47
  • Host C, 192.168.1.44
  • Host C, 192.168.1.60

Topology and configuration are the same as in the previous question. Host IP addresses are set as follows:

Host A, 192.168.1.13

Host B, 192.168.1.50

Host C, 192.168.1.58

Which statements are true? (Choose all that apply)

  • Host A can receive messages from host B
  • Host A can receive messages from host C
  • Host B can receive messages from host A
  • Host C can receive messages from host A

A router-on-a-stick is configured as follows:

R(config)#interface f0/1.2

R(config-subif)#encapsulation dot1q 20

R(config-subif)#ip add 172.18.0.1 255.255.255.128

R(config-subif)#interface f0/1.3

R(config-subif)#encapsulation dot1q 30

R(config-subif)#ip add 172.18.0.161 255.255.255.224

R(config-subif)#interface f0/1.4

R(config-subif)#encapsulation dot1q 40

R(config-subif)#ip add 172.18.0.193 255.255.255.224

R(config-subif)#interface f0/1

R(config-if)#no shutdown

The router receives a frame on physical interface f0/1. The destination IP address is 172.18.0.120. What will the router do?

  • Drop the frame because the IP address is not on a known network.
  • Send the frame out of interface f0/2.
  • Send the frame out of interface f0/1.2 tagged for VLAN 2.
  • Send the frame out of interface f0/1.2 tagged for VLAN 20.

Which is true of inter-VLAN routing using “router-on-a-stick”?

  • Not every router is able to create subinterfaces for VLANs. It depends on the IOS features.
  • It is possible if the switch uses IEE802.1Q tagging, but not if the switch uses ISL.
  • The router has to be running a routing protocol that supports VLSM.
  • The configuration is simpler than if separate physical interfaces are used, but the cabling is more complicated.

How are default gateways configured for inter-VLAN routing when “router-on-a-stick” is used?

  • All PCs attached to the switch will share the same default gateway since there is only one physical connection to the router.
  • PCs on different VLANs must be configured with different default gateways.
  • PCs must be configured with the same default gateway as the switch.
  • The switch default gateway is the IP address of the physical interface on the router.

What is true about MAC addresses when “router-on-a-stick” is usedfor inter-VLAN routing?

  • Each subinterface on the router has its own MAC address.
  • Each default gateway at layer 3 is linked with a different MAC address at layer 2.
  • Each physical Ethernet interface on the router has one MAC address.
  • The MAC address of the router interface is not used when the interface is configured for trunking.

SW 23/10/2007Document21