INTER-VLAN ROUTING

INTER-VLAN ROUTING

Inter-VLAN routing is the process of forwarding network traffic from one VLAN to another VLAN using a router.

To Create a VLAN on a Switch

Configure VLAN on switch

Syntax:

Switch(config)#vlan <VLAN No.>

Switch(config-vlan)#name <name>



To assign a interface to VLAN


Switch(config)#interface <type> <No.>

Switch(config-if)#switchport mode access

Switch(config-if)#switchport access vlan <VLAN No.>

Switch(config-if)#exit 



To configure a trunk link on interface connected to router

Switch(config)#interface <type> <No.>

Switch(config-if)#switchport mode trunk

Switch(config-if)#switchport trunk allowed vlan all

Switch(config-if)#exit

To configure inter-VLAN routing on a router

Configuration required on the ethernet interface. 

Syntax:

Router(config)#interface <type> <No.>

Router (config-if)#no shutdown

Router (config-if)#no ip address

Router (config-if )#exit

To configure sub interface on a router Configuration on sub interface of a Router:

Router(config)#interface <type> <Physical int no.sub int no> 

Router (config-if)#encapsulation dotlq <vlan no> [native] 

Router (config-if)#no ip address 

Router (config-if)#exit

Configuration on Switch :-

Create VLAN on switch:

switch#configure terminal 

switch(config)#vlan 10 

switch(config-vlan)#name Admin 

switch(config-vlan)#exit 

switch(config)#vlan 20 

switch(config-vlan)#name Accounts 

switch(config-vlan)#exit 

switch(config)#interface range fa0/2-4 

switch(config-if-range)#switchport mode access 

switch(config-if-range)#switchport access vlan 10 

switch(config-if-range)#exit 

switch(config)#interface range fa0/5-7 

switch(config-if-range)#switchport mode access 

switch (config-if-range)#s witch port access vlan 20 

switch(config-if-range)#exit 

switch(config)#interface fa0/1 

switch(config-if)#switchport mode trunk 

switch(config-if)#switchport trunk allowed vlan all 

switch(config-if)#ctrl+z

To verify the output using following commands:

switch#show vlan 

switch#show interface trunk

Configuration on Router :-

Router#configure terminal 
Router(config)#interface fastethernet 0/0
Router(config-if)#no ip address
Router(config-if)#no shutdown
Router(config-if)#exit
Router(config)#interface fastethernet 0/0.1
Router(config-if)#encapsulation dot1q 10
Router(config-if)#ip address 10.0.0.1 255.0.0.0
Router(config-if)#exit
Router(config)#interface fastethernet 0/0.2
Router(config-if)#encapsulation dot1q 20
Router(config-if)#ip address 11.0.0.1 255.0.0.0
Router(config-if)#exit

Router(config)#no ip routing 

Router(config)#ip routing 

Router(config)#exit

To verify the output using following commands:

Router#show ip route

Router#show running-config

OUTPUT:

Switch1#show vlan

Switch1#sh interfaces trunk 
Port        Mode            Encapsulation     Status           Native vlan
Fa0/1      on                802.1q               trunking            1

Port        Vlans allowed on trunk
Fa0/1      1-1005

Port        Vlans allowed and active in management domain
Fa0/1      1,10,20

Port        Vlans in spanning tree forwarding state and not pruned
Fa0/1      1,10,20




Kolkata#sh ip route
Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGP
       D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
       N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
       E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP
       i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, ia - IS-IS inter area
       * - candidate default, U - per-user static route, o - ODR
       P - periodic downloaded static route

Gateway of last resort is not set

C    10.0.0.0/8 is directly connected, FastEthernet0/0.1

C    11.0.0.0/8 is directly connected, FastEthernet0/0.2