Switching Fundamentals

Question 1

Each VLAN is its own ___.

Answer 1

Broadcast domain.

Question 2

Inter-VLAN traffic requires a ___.

Answer 2

Layer 3 device.

Question 3

Define a VMPS.

Answer 3

VLAN membership policy server. Used for dynamic VLANs.

Question 4

How do dynamic VLANs work?

Answer 4

The source address of a frame is matched against a VMPS database to determine the frame’s VLAN. Disables port security.

Question 5

Define a VVID.

Answer 5

Voice VLAN. A VLAN dedicated to moving voice traffic. Configured on a by-port basis.

Question 6

Explain how dot1p voice tagging works.

Answer 6

Voice traffic is granted high priority, and is sent through VLAN 0.

Question 7

Explain how dot1p voice tagging works.

Answer 7

Voice traffic is granted high priority, and is sent through VLAN 0.

Question 8

Explain how untagged voice tagging works.

Answer 8

Voice traffic is sent through the native VLAN.

Question 9

Briefly describe ISL.

Answer 9

Inter-Switch Link. Old-school Cisco proprietary. Tags every single frame, with both a header and trailer.

Question 10

Briefly describe 802.1q.

Answer 10

Dot1q. Standard tagging protocol. Puts a 4-byte tag inside of each frame. Allows native tagging.

Question 11

What is the MAC range for multicast frames?

Answer 11

0100.5e00.0000-0100.5e7f.ffff

Question 12

List the three PoE standards and their supported wattage.

Answer 12

802.3af (15.4) 802.3at - PoE+ (25.5) UPoE (60)

Question 13

Does ISL support untagged frames?

Answer 13

No.

Question 14

How many bytes does an ISL tag take?

Answer 14

Total of 30 bytes.

Question 15

How many bytes does a 802.1q encapsulation take?

Answer 15

Total of 4 bytes.

Question 16

ISL tagging allows for CRC. What is CRC?

Answer 16

Cyclic redundancy check. Allows the frame recipient to test the integrity of the frame based on an algorithm.

Question 17

The native VLAN is a VLAN designated to send ___ frames on a port-by-port basis.

Answer 17

Untagged.

Question 18

What happens if the native VLANs on two peer-to-peer trunks mismatch?

Answer 18

The ports will be blocked.

Question 19

When running “show int trunk”, what does the output “n-“ designate?

Answer 19

The encapsulation type (ISL or 802.1q) was auto-negotiated.

Question 20

What command can be used to show the status of a switchport mode trunk port that is not currently trunking?

Answer 20

Show interface ___ trunk

Question 21

How do you hard-code a port to not trunk?

Answer 21

Put it into access mode.

Question 22

Voice traffic should always be configured using a ___ & ___.

Answer 22

Trunk and VVID.