💻 Learn how Inter-VLAN Routing works, its types, configurations, and best practices!
Introduction
In computer networking, VLANs (Virtual Local Area Networks) are used to segment a network for better security and efficiency. However, VLANs cannot communicate with each other by default. To enable communication between VLANs, we use Inter-VLAN Routing. This guide will explain everything you need to know about Inter-VLAN Routing, including its types, configurations, and best practices.
What is VLAN /https://techbyrathore.blogspot.com/2025/03/what-is-vlan-and-how-it-works.html
What is Inter-VLAN Routing?
Inter-VLAN Routing is the process
that allows communication between different VLANs. Since VLANs are separate broadcast
domains, they cannot communicate without a router or a Layer 3 device.
DHCP complete guide;
https://www.dignited.com/32591/dhcp-dynamic-host-configuration-protocol/
Basics of routing you should know;
https://techbyrathore.blogspot.com/2025/03/routing-basics-guide.html
Why is Inter-VLAN Routing Important?
✅ Allows devices in different VLANs
to communicate.
✅ Improves network security by segmenting traffic.
✅ Enhances network performance by controlling data flow.
Types
of Inter-VLAN Routing
There are three main methods of
Inter-VLAN Routing:
1.
Traditional Inter-VLAN Routing (Router-on-a-Stick)
- Uses a router with multiple sub-interfaces.
- Each VLAN is assigned to a sub-interface on the router.
- The router routes traffic between VLANs.
- Best for small networks but not scalable.
2.
Layer 3 Switch Inter-VLAN Routing (SVI - Switched Virtual Interface)
- Uses a Layer 3 switch with SVI (Switched
Virtual Interface).
- No need for an external router.
- Faster and scalable
for enterprise networks.
3.
Inter-VLAN Routing Using Routed Ports
- Uses Layer 3 switch with dedicated routed ports.
- Each port acts as a separate router interface.
- Used in large-scale networks with high
performance needs.
Inter-VLAN
Routing Configuration (Step-by-Step)
1.
Configure VLANs on the Switch
bash
CopyEdit
Switch(config)#
vlan 10
Switch(config-vlan)#
name Sales
Switch(config-vlan)#
vlan 20
Switch(config-vlan)#
name HR
2.
Assign Ports to VLANs
bash
CopyEdit
Switch(config)#
interface fa0/1
Switch(config-if)#
switchport mode access
Switch(config-if)#
switchport access vlan 10
bash
CopyEdit
Switch(config)#
interface fa0/2
Switch(config-if)#
switchport mode access
Switch(config-if)#
switchport access vlan 20
3.
Enable Routing on the Layer 3 Switch
bash
CopyEdit
Switch(config)#
ip routing
4.
Create SVIs for VLANs
bash
CopyEdit
Switch(config)#
interface vlan 10
Switch(config-if)#
ip address 192.168.10.1 255.255.255.0
Switch(config-if)#
no shutdown
bash
CopyEdit
Switch(config)#
interface vlan 20
Switch(config-if)#
ip address 192.168.20.1 255.255.255.0
Switch(config-if)# no shutdown
5.
Assign Default Gateway to PCs
On PC in VLAN 10:
nginx
CopyEdit
IP
Address: 192.168.10.2
Subnet
Mask: 255.255.255.0
Default
Gateway: 192.168.10.1
On PC in VLAN 20:
nginx
CopyEdit
IP
Address: 192.168.20.2
Subnet
Mask: 255.255.255.0
Default
Gateway: 192.168.20.1
6.
Test Connectivity
bash
CopyEdit
PC1> ping 192.168.20.2
Best Practices for Inter-VLAN Routing
✅ Use Layer 3 Switches for
high-performance networks.
✅ Use VLAN Access Control Lists (VACLs) for security.
✅ Enable STP (Spanning Tree Protocol) to prevent loops.
✅ Monitor traffic using SNMP or NetFlow.
FAQs
About Inter-VLAN Routing
1.
Can VLANs communicate without a router or Layer 3 switch?
No, VLANs are separate broadcast domains.
They need a router or Layer 3 switch to communicate.
2.
Which method is best for large networks?
https://www.geeksforgeeks.org/inter-vlan-routing-layer-3-switch/
Using Layer 3 switches with SVIs
is the best method for large-scale networks.
3.
What is the difference between VLAN and Inter-VLAN Routing?
- VLAN
separates network segments.
- Inter-VLAN Routing allows communication between VLANs.
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