CCNA 2 Module 3 Quiz – VLANs (Answers)

1. What happens to a port that is associated with VLAN 10 when the administrator deletes VLAN 10 from the switch?

  • The port creates the VLAN again.
  • The port goes back to the default VLAN.
  • The port automatically associates itself with the native VLAN.
  • The port becomes inactive.
Explanation: If the VLAN that is associated with a port is deleted, the port becomes inactive and cannot communicate with the network any more. To verify that a port is in an inactive state, use the show interfaces switchport command.

2. In which memory location are the VLAN configurations of normal range VLANs stored on a Catalyst switch?

  • flash
  • ROM
  • RAM
Explanation: When a normal range VLAN is created the configuration information of the VLAN is stored in flash in the vlan.dat file.

3. An administrator is investigating a failure on a trunk link between a Cisco switch and a switch from another vendor. After a few show commands, the administrator notices that the switches are not negotiating a trunk. What is a probable cause for this issue?

  • Both switches are in nonegotiate mode.
  • Switches from other vendors do not support DTP.
  • Both switches are in trunk mode.
  • DTP frames are flooding the entire network.
Explanation: DTP is a Cisco proprietary protocol. Non-Cisco switches do not support DTP.

4. What is the purpose of the vlan.dat file on a switch?

  • It holds the VLAN database.
  • It holds the running configuration.
  • It holds the operating system.
  • It holds the saved configuration.
Explanation: The VLAN database (vlan.dat) contains information about normal range VLANs such as the VLAN number, name, and VTP mode.

5. What is the purpose of setting the native VLAN separate from data VLANs?

  • A separate VLAN should be used to carry uncommon untagged frames to avoid bandwidth contention on data VLANS.
  • The security of management frames that are carried in the native VLAN can be enhanced.
  • The native VLAN is for carrying VLAN mnanagement traffic only.
  • The native VLAN is for routers and switches to exchange their management information, so it should be different from data VLANS.
Explanation: When a Cisco switch trunk port receives untagged frames (unusual in well-designed networks), it forwards these frames to the native VLAN. When the native VLAN is moved away from data VLANs, those untagged frames will not compete for bandwidth in the data VLANs. The native VLAN is not designed for carrying management traffic, but rather it is for backward compatibility with legacy LAN scenarios.

6. When a Cisco switch receives untagged frames on a 802.1Q trunk port, which VLAN ID is the traffic switched to by default?

  • management VLAN ID
  • data VLAN ID
  • native VLAN ID
  • unused VLAN ID
Explanation: A native VLAN is used to forward untagged frames that are received on a Cisco switch 802.1Q trunk port. Untagged frames that are received on a trunk port are not forwarded to any other VLAN except the native VLAN.

7. A network administrator is determining the best placement of VLAN trunk links. Which two types of point-to-point connections utilize VLAN trunking?​ (Choose two.)

  • between two switches that utilize multiple VLANs
  • between a switch and a server that has an 802.1Q NIC
  • between a switch and a network printer
  • between two switches that share a common VLAN
  • between a switch and a client PC
Explanation: VLAN trunk links are used to allow all VLAN traffic to propagate between devices such as the link between a switch and a server that has an 802.1Q-capable NIC. Switches can also utilize trunk links to routers, servers, and to other switches.

8. What are three primary benefits of using VLANs? (Choose three.)

  • end user satisfaction
  • cost reduction
  • a reduction in the number of trunk links
  • security
Explanation: Security, cost reduction, and improved IT staff efficiency are all benefits of using VLANs, along with higher performance, broadcast storm mitigation, and simpler project and application management. End users are not usually aware of VLANs, and VLANs do require configuration. Because VLANs are assigned to access ports, they do not reduce the number of trunk links.

9. On a Cisco switch, where is extended range VLAN information stored?

  • running configuration file
  • flash
  • startup configuration file
Explanation: Extended range VLANs, 1006 through 4094, are not written to the vlan.dat file but are saved in the running configuration file.

10. In which location are the normal range VLANs stored on a Cisco switch by default?

  • RAM
  • flash memory
  • startup-config
  • running-config
Explanation: Normal range VLANs are stored in a file called vlan.dat and located in the flash memory.

11. Which distinct type of VLAN is used by an administrator to access and configure a switch?

  • data VLAN
  • default VLAN
  • native VLAN
  • management VLAN
Explanation: A management VLAN is used to remotely access and configure a switch. Data VLANs are used to separate a network into groups of users or devices. The default VLAN is the initial VLAN all switch ports are placed in when loading the default configuration on a switch. The 802.1Q trunk port places untagged traffic on the native VLAN.

12. For what reason would a network administrator use the show interfaces trunk command on a switch?

  • to view the native VLAN
  • to examine DTP negotiation as it occurs
  • to display an IP address for any existing VLAN
  • to verify port association with a particular VLAN
Explanation: The show interfaces trunk command displays the ports that are trunk ports, the trunking mode, the encapsulation type, the trunk status, the native VLAN, and the allowed VLANs on the link.

13. Where is the vlan.dat file stored on a switch?

  • in NVRAM
  • in flash memory
  • in RAM
  • on the externally attached storage media or internal hard drive
Explanation: Normal range VLAN configurations are stored within a VLAN database file, called vlan.dat, which is located in the flash memory of the switch.

14. If an organization is changing to include Cisco IP phones in its network, what design feature must be considered to ensure voice quality?

  • Voice traffic needs to be tagged with the native VLAN.
  • A separate VLAN is needed for voice traffic.
  • Voice traffic and data traffic require separate trunk links between switches.
  • Additional switch ports that are dedicated to Cisco IP phones are required.
Explanation: A PC commonly connects to an IP phone and the IP phone, in turn, connects to a switch. The phone does not require a separate port. Because voice traffic cannot tolerate much packet delay, it needs to be in a separate VLAN. The voice VLAN can be configured to provide quality of service (QoS), which will ensure that the voice traffic has a higher priority than data traffic.

15. A Cisco switch currently allows traffic tagged with VLANs 10 and 20 across trunk port Fa0/5. What is the effect of issuing a switchport trunk allowed vlan 30 command on Fa0/5?

  • It allows a native VLAN of 30 to be implemented on Fa0/5.
  • It allows VLANs 10, 20, and 30 on Fa0/5.
  • It allows only VLAN 30 on Fa0/5.
  • It allows VLANs 1 to 30 on Fa0/5.
Explanation: The switchport trunk allowed vlan 30 command allows traffic that is tagged with VLAN 30 across the trunk port. Any VLAN that is not specified in this command will not be allowed on this trunk port.

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