Muftasoft TM

Inter-VLAN routing is essential for enabling communication between different VLANs within a network. Let's explore the three common methods of implementing inter-VLAN routing:

1. Traditional Inter-VLAN Routing:

1. In this method, a router with multiple physical interfaces is used.
2. Each interface on the router is connected to a switch, with one interface per VLAN.
3. The switch ports connected to the router are typically in access mode.
4. Each router interface becomes the default gateway address for hosts in its associated VLAN.
5. When hosts from different VLANs need to communicate, traffic is routed through the router.
6. This approach involves physical interfaces and is suitable for smaller networks.

2. Router-on-a-Stick Inter-VLAN Routing:

1. Also known as “subinterface” routing, this method uses a single router interface.
2. The router interface is configured with subinterfaces, each associated with a specific VLAN.
3. The subinterfaces are virtual interfaces that allow the router to handle traffic from multiple VLANs.
4. A trunk link connects the router interface to a switch, carrying traffic for all VLANs.
5. The router performs inter-VLAN routing based on the VLAN tags in the frames.
6. This approach is efficient for larger networks and reduces the need for multiple physical interfaces.

3. Multilayer Switch Inter-VLAN Routing:

1. Multilayer switches (Layer 3 switches) combine switching and routing capabilities.
2. They have VLAN interfaces (SVIs) for each VLAN, acting as virtual router interfaces.
3. SVIs allow the switch to route traffic between VLANs without an external router.
4. The switch maintains a routing table and performs inter-VLAN routing in hardware.
5. This method is efficient, especially in large networks, as it avoids bottlenecks caused by a single router.

Now, let's configure a basic example using a multilayer switch:

1. Enable Routing Capability:

1. On the switch, ensure that IP routing is enabled:

```

   Switch(config)# ip routing
   ```

2. Create VLANs:

1. Define the VLANs that need to be routed (e.g., VLAN 10, VLAN 20, and VLAN 30).

3. Assign IP Addresses to VLAN Interfaces:

1. Configure IP addresses for the VLAN interfaces (SVIs):

```

   Switch(config)# interface vlan10
   Switch(config-if)# ip address 192.168.10.1 255.255.255.0
   Switch(config-if)# no shutdown
   Switch(config-if)# exit

   Switch(config)# interface vlan20
   Switch(config-if)# ip address 192.168.20.1 255.255.255.0
   Switch(config-if)# no shutdown
   Switch(config-if)# exit

   Switch(config)# interface vlan30
   Switch(config-if)# ip address 192.168.30.1 255.255.255.0
   Switch(config-if)# no shutdown
   Switch(config-if)# exit
   ```

4. Configure Hosts:

1. Set the default gateway for hosts in each VLAN to the corresponding SVI IP address (e.g., 192.168.10.1 for VLAN 10).

Remember that inter-VLAN routing enhances network flexibility and security, allowing efficient communication across VLANs. Feel free to explore more advanced configurations based on your network requirements! 🌐🔗