Layer 3 Switch Configuration: SVI Setup & Inter-VLAN Routing in Packet Tracer

As networks expand, effective network management becomes increasingly important. One key aspect of network management is inter-VLAN routing, which allows for efficient communication between different VLANs within a network.

While Router on a Stick (ROAS) configurations have traditionally been used for inter-VLAN routing, Layer 3 switches offer an alternative approach through the use of Switched Virtual Interfaces (SVIs). SVIs provide a virtual interface that allows VLANs to be configured and achieve inter-VLAN routing capabilities.

In this post, we will guide you through the Layer 3 Switch Configuration in Cisco Packet Tracer, specifically focusing on implementing inter-VLAN routing using SVIs.

In our previous post, we showed how to implement inter-vlan routing using Router on a Stick (ROAS). In this post, I will be using the same netowk topology and migrating the ROAS configuration to the SVI configuration for inter-vlan routing.

If you’re unfamiliar with trunk port configuration and how it leverages VLAN tags to enhance inter-VLAN routing, we recommend checking out our previous post on the subject. For the purpose of this article, we will assume prior knowledge of trunkport configuration and go straight into the SVI setup for inter-VLAN routing.

So, let’s dive right in.

What is a Layer 3 Switch?

A layer 3 switch, also referred to as a multi-layer switch, is a switch that is capable of both routing and switching. It has virtual interfaces, and to make it work as a router, you need to assign IP addresses to those interfaces and connect it to VLANs.

What are Switch Virtual Interfaces (SVI) in Layer 3 switches?

Switch virtual interfaces (SVI) are the interfaces that you can assign an IP address to on a Layer 3 switch. This interface is connected to a vlan, and all the host devices on such a vlan will use the virtual interface IP address as their default gateway.

Network Topology

The network topology shown below is what we will be using to demonstrate layer 3 switch configuration for inter-vlan routing. This network topology is the same as what we used in the Router on a Stick configuration for inter-vlan routing, except that the router has been removed and the layer 2 switch has been replaced with a layer 3 switch.

The topology consists of two switches (one layer 2 and the other layer 3) connected with a trunk link.  We have done the necessary configuration for the host devices in those vlans.

Note: This topology is used for demonstration purposes, and the topology may differ in real-world scenarios.
The main goal of this article is to configure the SVIs for vlan 10, vlan 20, and vlan 30. After this configuration, We will be able to send traffic from one vlan to another.

Note: We had already configured trunkport on the G0/1 interface of switches 1 and 2 in our article on trunkport configuration. So we won’t cover that in this post. You can also check the access port configuration for this network.

Layer 3 Switch Configuration for Inter-VLAN Routing

To configure a Layer 3 switch for inter-VLAN routing using SVIs, you can follow these steps;

1. Access the configuration mode for the switch: Double tap on the switch and enter he following command to access the global configuration mode.

SW2>enable
SW2#configure terminal
SW2(config)#ip routing

2.Create VLANs and assign VLAN IDs: on the global configuration mode, enter the following command to create the VLANs you will work with the in layer 3 switch.

SW2(config)#vlan VLAN ID

Remember to replace the “ID” in command above with the specific ID you want to use.

In our case, we used the below command to create vlan 10, vlan 20 and vlan 30 which we need for the network topology shown above.

SW2(config)#vlan 10
SW2(config)#vlan 20
SW2(config)#vlan 30

3.Assign Layer 3 interfaces to VLANs: After creating the VLANs, you need to assign the Layer 3 interfaces (SVIs) to each VLAN. Use the following command to assign the SVI to a VLAN:

SW2(config)#interface vlan VLAN ID
SW2(config-if)#no switchport
SW2(config-if)#ip address IP_ADDRESS SUBNET_MASK 

Replace “VLAN ID” with the ID of the VLAN you are configuring, “IP_ADDRESS” with the desired IP address for the SVI, and “SUBNET_MASK” with the appropriate subnet mask.

For example, to assign the SVI to VLAN 10 of the network topology above we used the following commands:

SW2(config)#interface vlan 10 
SW2(config-if)#no switchport
SW2(config-if)#ip address 10.0.0.62 255.255.255.192
SW2(config-if)#no shutdown

We entered the following command to configure the remaining vlans in the above network topology.

SW2(config)#interface vlan 20
SW2(config-if)#ip address 10.0.0.126 255.255.255.192
SW2(config-if)#no switchport
SW2(config-if)#no shutdown
SW2(config-if)#interface vlan 30
SW2(config-if)#no switchport
SW2(config-if)#ip address 10.0.0.190 255.255.255.192
SW2(config-if)#no shutdown

4.Verify the configuration: Once you have completed the SVI configuration, verify the settings using the following commands:

SW2#show vlan brief 
SW2#show ip interface brief

When you issue the first command, you should see something like;

The picture shows a summary of the VLANs and their associated interfaces.

When you issue the second command, you should see;

 

The image above shows the configured IP addresses for the SVIs. You can see it in the bottom section of the image.

5. Test inter-VLAN communication: With the SVIs configured and enabled, we can now test inter-VLAN communication by pinging from one PC to another PC in another VLAN.

The video below shows the successful pining from a PC in one VLAN to another PC in another VLAN.

Conclusion

With what we have covered on this post, I believe you have learned Layer 3 Switch Configuration for inter-VLAN routing .

From the video above, you have seen that Layer 3 switches provide an efficient alternative to Router on a Stick (ROAS) configurations, allowing for faster inter-VLAN routing and simplified network management.

If you have any questions, do leave them in the beginning section below, and I will attend to them as soon as possible