WHAT IS VLAN?
WHAT IS VLAN?
VLAN (Virtual Local Area Network) Definition:
VLAN is the logical grouping of ports on same or different devices, which becomes separate broadcast domain.
The devices can be located at the same location or different location. VLANs are based on logical instead of physical connections.
Meaning of Broadcast domain:
In a new switch, all the ports are part of a single broadcast domain
If traffic comes from any port of the switch to any destination in the switch, searching process for destination will be done across all the ports.
Technically, ARP request will go to every port to find out the destination
By creating VLAN’s means, we are dividing single broadcast domain into multiple broadcast domain.
In simple words,
We have a switch with 10 ports.
Two VLAN’s are created, VLAN 5 & 6.
1-5 ports are assigned to VLAN 5 and 6-10 ports are assigned to VLAN 6
If traffic comes from any port in-between port 1-5, searching process will be done in ports 1-5,
To find out the destination port
Similarly, if traffic comes from any port in-between port 6-10, searching process will be done in ports
6-10, to find out the destination port
If there are no VLAN’s, if traffic comes from any port of the switch, searching process will be done in
All the ports of the switch, there is no division
- Access Port: It can carry traffic of one VLAN
- Trunk port: It can carry traffic of more than one VLAN
How to create VLAN’s?
There are two types of VLAN: L2 and L3 VLAN
Configuration for L2 VLAN:
Switch#vlan 10 Created
Switch#sh running-config vlan 10 Verified
/IP cannot be provided to L2 VLAN/
Configuration for L3 VLAN:
Switch# interface vlan 10 Created
Switch#sh running-config interface vlan 10 Verified
/IP can be provided to L3 VLAN/
- 1 VLAN=1 Broadcast Domain
- 1 Subnet or Network is assigned to one VLAN. Separate VLAN means separate subnet or network
- In a new switch, all ports are access ports and assigned to the same VLAN, Default VLAN (VLAN 1)
- If further division is required into the VLAN, we have the option of Private VLAN.Private VLAN will be discussed in some other post
- IP cannot be provided to L2 VLAN
- IP can be provided to L3 VLAN