All the methods of Inter-Vlan Routing configuration

When you want to establish communication between different VLANs you will need a device that can do routing. You could use an external router with separate physical gateways or sub-interface (router on stick) method but it’s also possible to use a multilayer switch. 

The router must have a physical or logical connection to each VLAN so that it can forward packets between VLANs.

Let’s see the first method router with separate physical gateways:-

Topology:

Goal:

• configure the topology as per our diagram  and  the assign the IP addresses.
• create VLAN 101 sales and VLAN 102 marketing and assign the interfaces to their VLAN as per the diagram

Router(config)#interface fastEthernet 0/0
Router(config-if)#ip address 192.168.10.1 255.255.255.0
Router(config-if)#no shutdown
Router(config-if)#exit

%LINK-5-CHANGED: Interface FastEthernet0/0, changed state to up
%LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/0, changed state to up

Router(config)#interface fastEthernet 0/1
Router(config-if)#ip address 192.168.20.1 255.255.255.0
Router(config-if)#no shutdown
Router(config-if)#exit

%LINK-5-CHANGED: Interface FastEthernet0/1, changed state to up
%LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/1, changed state to up

Router#show ip interface brief
Interface               IP-Address       OK? Method    Status    Protocol

FastEthernet0/0    192.168.10.1    YES manual     up        up
FastEthernet         192.168.20.1    YES manual     up        up

Switch(config)#vlan 101

Switch(config-vlan)#name sales
Switch(config-vlan)#exit

Switch(config)#vlan 102
Switch(config-vlan)#name marketing

Switch(config-vlan)#exit

Switch(config)#interface range fastEthernet 0/1-2
Switch(config-if-range)#switchport mode access
Switch(config-if-range)#switchport access vlan 101
Switch(config-if-range)#exit

Switch(config)#interface range fastEthernet 0/3-4
Switch(config-if-range)#switchport mode access
Switch(config-if-range)#switchport access vlan 102

Switch(config-if-range)#exit

Switch(config)#interface fastEthernet 0/5
Switch(config-if)#switchport mode access
Switch(config-if)#switchport access vlan 101
Switch(config-if)#exit

Switch(config)#interface fastEthernet 0/6
Switch(config-if)#switchport mode access
Switch(config-if)#switchport access vlan 102

Switch(config-if)#exit

FROM HOST 1

lets see from HOST 4

FROM HOST 4

A router on stick can be used to route between VLANs using either ISL or IEEE 801.1Q as the trunking protocol. its requires sub-interface for each respective VLAN.

NOTE: whatever is your VLAN number its should be exact on sub-interface.

Let see the configuration using sub-interface (router on stick)

Topology:-

Goal:

• configure the topology as per the diagram and assign the IP addresses 
• configure VLAN 101 and VLAN 102
• assign the port to their respective VLANs
• configure sub-interfaces on router fast Ethernet 0/0 assign IP address as per the topology
• ensure the connectivity between VLAN 101 and VLAN 102, make sure HOST 1 (VLAN 101) IS able to ping HOST 4 (VLAN 102).

Switch(config)#vlan 101
Switch(config-vlan)#name sales
Switch(config-vlan)#exit

Switch(config)#vlan 102
Switch(config-vlan)#name marketing
Switch(config-vlan)#exit

Switch(config)#interface range fastEthernet 0/1-2
Switch(config-if-range)#switchport mode access
Switch(config-if-range)#switchport access vlan 101
Switch(config-if-range)#exit

Switch(config)#interface range fastEthernet 0/3-4
Switch(config-if-range)#switchport mode access
Switch(config-if-range)#switchport access vlan 102

Switch(config-if-range)#exit

Switch(config)#interface fastEthernet 0/5
Switch(config-if)#switchport trunk encapsulation dot1q
Switch(config-if)#switchport trunk allowed vlan 101,102

Switch(config-if)#exit

Router(config)#interface fastEthernet 0/0
Router(config-if)#no shutdown
Router(config-if)#exit

Router(config)#interface fastEthernet 0/0.101
Router(config-subif)#encapsulation dot1Q 101
Router(config-subif)#ip address 192.168.10.1 255.255.255.0
Router(config-subif)#exit

Router(config)#interface fastEthernet 0/0.102
Router(config-subif)#encapsulation dot1Q 102
Router(config-subif)#ip address 192.168.20.1 255.255.255.0

Router(config-subif)#exit

%LINK-5-CHANGED: Interface FastEthernet0/0.102, changed state to up

%LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/0.102, changed state to up

Router#show ip interface brief
Interface                         IP-Address          OK?      Method   Status          Protocol
FastEthernet0/0             unassigned          YES      manual      up                    up
FastEthernet0/0.101      192.168.10.1       YES      manual      up                    up

FastEthernet0/0.102      192.168.20.1       YES      manual      up                    up

from host 1

from host 4