Thursday 16 July 2015

Configure Vlans on Cisco Switch

Vlans stands for virtual Lans means you are dividing users based on function or category.For ex-Vlan10 for Sales department,Vlan20 for Accounts,Vlan30 for Logistics and so on.You can create as many as vlans you want with Cisco switch like 2-1005.An easy way to understand this -Assume an office building with 3 floors with each floor has 5 users.We can then create separate Vlans based on floors like Vlan 10 for floor 1,Vlan 20 for floor 2 and so on.I have name them as Sales,Accounts and Logistics.Separating users with Vlans will create separate Broadcast Domain which you can say a Network area in which users can communicate.Creating 3 Vlans will create three Broadcast domain and user in one Vlan can't communicate with the user in the other Vlan.To provide connectivity between different Vlans,we need a Router (also a Layer 3 device).We are not dividing users physically,its logical division.Its convenient for troubleshooting,administration.To enable communication between these Vlans,we also need to give those Vlans IP addresses which i am going to publish in the coming days.

Steps to create Vlans :
Switch>
Switch>enable
Switch#configure terminal    (or conf t)
Switch(config)#vlan 10
Switch(config-vlan)#name sales
Switch(config-vlan)#vlan 20
Switch(config-vlan)#name Accounts
Switch(config-vlan)#vlan 30
Switch(config-vlan)#name Logistics
Switch(config-vlan)#exit




Place hosts to specific vlans :

To place specific hosts into a vlans,we can use interface range fa0/1-5 command if there are more than one users or we can use interface fa0/1 to place a single host to a vlan.

In global configuration mode :
For single host -
Switch(config)#interface fa0/1
Switch(config-if)#switchport mode access
Switch(config-if)#switchport  access vlan 10

For multiple hosts-

Switch(config)#interface range fastEthernet 0/1-5
Switch(config-if)#switchport mode access
Switch(config-if)#switchport  access vlan 10


Switchport mode access command is used to make that interface an access port so that it can't negotiate trunking which we will cover later.

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