VLAN interview questions and answers

 

What is VLAN and how
does it function?

 A VLAN, or Virtual
Local Area Network, is a way to segment a physical network into logical
subgroups. This allows for greater network organization and security, as well
as the ability to segment network traffic.

 

What is the difference
between a VLAN and a subnet?

A VLAN segments a physical network into logical subgroups,
while a subnet segments a larger IP address space into smaller subgroups.

 

How does VLAN tagging
work?

VLAN tagging is a method of identifying packets as belonging
to a specific VLAN. This is done by adding a VLAN tag, or header, to the
packet, which includes information such as the VLAN ID and priority. VLAN
tagging allows for the segregation of different types of traffic, such as voice
and data, on the same physical network.

 

How do you configure a
VLAN on a switch?

The process for configuring a VLAN on a switch will vary
depending on the specific switch and its operating system. However, the general
steps include:

Logging into the switch and entering configuration mode

Creating a VLAN by assigning it a unique ID and a name

Assigning switch ports to the VLAN

Configuring any necessary VLAN tagging or trunking.

Saving the configuration changes.

 

Why we create VLANs?

Broadcast control, Performance, Security, Department wise
segmentation.

 

 

How to delete VLAN?

VLAN info not saved in running config and startup config of
the switch its saved in VLAN.dat in

Flash memory.

 

Difference between
trunk and Access port?

Access Port- Carry traffic of single VLAN.

Trunk Port – Carry traffic of multiple VLAN, by defaults all
vlans are allowed on trunk.

 

What is inter-VLAN
routing?

When host from one VLAN want to communicate with host in
other VLAN traffic must be routed

Between them. that is called inter VLAN routing.

Difference between ISL and IEEE 802.1Q ?

ISL—Cisco Propriety.

          Original
frame encapsulates with 26-byte header and 4-byte FCS

802.1Q- Industry Standard.

               Only 4-byte
tag. tag.

 

VLAN range?

VLAN range 0-4096

Default VLAN    1

Normal VLAN range 2-1001

Reserved for token ring 1002-1005

Extended VLAN 1006-4095