VLAN interview questions and answers
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.
A VLAN segments a physical network into logical subgroups, while a subnet segments a larger IP address space into smaller subgroups.
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.
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.
Broadcast control, Performance, Security, Department wise segmentation.
VLAN info not saved in running config and startup config of the switch its saved in VLAN.dat in
Flash memory.
Access Port- Carry traffic of single VLAN.
Trunk Port – Carry traffic of multiple VLAN, by defaults all vlans are allowed on trunk.
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 0-4096
Default VLAN
1
Normal VLAN range 2-1001
Reserved for token ring 1002-1005
Extended VLAN 1006-4095
