1 Reply Latest reply: Jun 8, 2010 6:56 AM by Jared RSS





      How can we create a vlan on a router  ? Is there any particular configuration for that or it is the similar as we create it on a switch?





        • 1. Re: VLAN ON ROUTER

          A vlan configuration on a router is slightly different than on a switch.  On a switch, you would create the vlan and then the routed vlan interface.


          On a router you tie a vlan to a subinterface.  You need to create the subinterface and then do the encapsulation dot1q <vlan ID> command.  This command basically assigned the vlan to the subinterface.  In this example, there are 2 vlans, vlan 100 and 201.  On the eth 0/0 interface, I created two subinterfaces.  fastethernet0/0.100 and f0/0.201.  Notice that I matched the subinterface number with the vlan ID.  You do not have to do this, but it is a best practice and really helps you as the administrator keep things organized.  So, under f0/0.100, there is the encapsulation dot1q 100, which basically binds vlan 100 to subinterface f0/0.100, then I assigned the IP.  The same is for the other subinterface.  So the router is trunking two vlans on its f0/0 interface, vlan's 100 and 201.


          interface FastEthernet0/0
          no ip address
          speed 100
          interface FastEthernet0/0.100
          description test Network
          encapsulation dot1Q 100
          ip address
          no snmp trap link-status
          interface FastEthernet0/0.201
          description  Office
          encapsulation dot1Q 201
          ip address
          no snmp trap link-status