VLAN Questions

Question 1

Explanation

The Port Fast feature is automatically enabled when voice VLAN is configured. When you disable voice VLAN, the Port Fast feature is not automatically disabled.

Reference: http://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst3550/software/release/12-1_19_ea1/configuration/guide/3550scg/swvoip.html

Question 2

Explanation

802.1Q VLAN frames are distinguished from ordinary Ethernet frames by the insertion of a 4-byte VLAN tag into the Ethernet header.

Question 3

Explanation

Because the 802.1Q tunneling feature increases the frame size by 4 bytes when the metro tag is added, you must configure all switches in the service-provider network to be able to process maximum frames by increasing the switch system MTU size to at least 1504 bytes.

Question 4

Explanation

The VLAN ID field inside an 802.1q frame consists of 12 bits. Therefore we have 2¹² = 4096 VLAN IDs, theoretically.

Question 5

Explanation

Each access port can be only assigned to one VLAN via the “switchport access vlan ” command.

Question 6

Explanation

This command is used to enable tagging of native VLAN frames on all 802.1Q trunk ports.

Answer A is not correct because even when the native VLAN is set to 1, all of the frames of the native VLAN are tagged.

Answer B is not correct because the control traffic still passes via the default VLAN (VLAN 1).

Answer C is not correct because all the frames are tagged with 4-byte dot1Q tag.

Answer D is not correct as “Control traffic continues to be accepted as untagged on the native VLAN on a trunked port, even when the vlan dot1q tag native command is enabled” according to this link: https://www.cisco.com/c/m/en_us/techdoc/dc/reference/cli/nxos/commands/l2/vlan-dot1q-tag-native.html

Question 7

Explanation

When you delete a VLAN, any LAN ports configured as access ports assigned to that VLAN become inactive. The ports remain associated with the VLAN (and inactive) until you assign them to a new VLAN.

Reference: http://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst6500/ios/12-2SX/configuration/guide/book/vlans.html

Question 8

Explanation

The PortFast feature is automatically enabled when voice VLAN is configured. When you disable voice VLAN, the PortFast feature is not automatically disabled.

Question 9

Question 10