Cisco CCNA VLANs and 802.1Q Trunking Questions and Answers

Question 1

A network technician configures two PCs on a single Cisco switch.
PC-A is on port Fa0/1 in VLAN 10, and PC-B is on port Fa0/2 in VLAN 20.
Both PCs are assigned IP addresses in the 192.168.1.0/24 subnet.
The PCs are unable to ping each other.
What is the most likely cause of this issue?

Accepted Answer

A Layer 3 device is required to route between the VLANs.

Answer

The switch has a faulty port.

Answer

Spanning Tree Protocol has blocked one of the ports.

Answer

The PCs have incorrect default gateway settings.

Question 2

What is the primary function of the native VLAN on an IEEE 802.1Q trunk port?

Accepted Answer

To carry untagged traffic.

Answer

To encrypt all management traffic between switches.

Answer

To assign a VLAN ID to frames that arrive without one.

Answer

To exclusively carry VTP and CDP traffic.

Question 3

A network administrator needs to configure a switch port to permanently operate in trunking mode and carry traffic for multiple VLANs between switches. Which Cisco IOS command should be used on the interface?

Accepted Answer

switchport mode trunk

Answer

switchport mode dynamic auto

Answer

switchport mode access

Answer

switchport nonegotiate

Question 4

An administrator adds VLAN 50 to two switches that are connected by a trunk link. Devices in VLAN 50 on the first switch cannot communicate with devices in VLAN 50 on the second switch. The administrator has confirmed that VLAN 50 exists on both switches. Which of the following is the most likely reason for the problem?

Accepted Answer

VLAN 50 has not been added to the allowed list on the trunk ports.

Answer

A native VLAN mismatch exists on the trunk.

Answer

The switches are operating in different VTP modes.

Answer

Spanning Tree Protocol has blocked the trunk link for VLAN 50.

Question 5

The IEEE 802.1Q frame tag, used for identifying VLANs, is 4 bytes long and inserted into the Ethernet frame header. Which field within this tag is 12 bits long and specifies the VLAN membership of the frame?

Accepted Answer

VLAN Identifier (VID)

Answer

Tag Protocol Identifier (TPID)

Answer

Priority Code Point (PCP)

Answer

Canonical Format Indicator (CFI)

Question 6

A network administrator is connecting a Cisco IP phone to a switch port. A user's PC will be connected through the IP phone. The phone's voice traffic must be on VLAN 15 (voice), and the PC's data traffic must be on VLAN 10 (data). Which switch feature is designed for this scenario?

Accepted Answer

Voice VLAN

Answer

Port Security

Answer

Native VLAN

Answer

VLAN Trunking Protocol (VTP)