Lab Project 5 - Configure Inter-Vlan Routing

This project, authored by Seng Chiboung, demonstrates the setup and evolution of Inter-VLAN routing across three different network topologies: Legacy Inter-VLAN Routing, Router-on-a-Stick (ROAS), and Layer 3 Switch Inter-VLAN Routing.

Project Description
By default, Layer 2 switches isolate broadcast domains, preventing devices in different VLANs from communicating. This lab illustrates how a Layer 3 device (router or multilayer switch) routes traffic between separate subnets:

VLAN 10 Network: 172.16.10.0/24 (Gateway: 172.16.10.1)

VLAN 20 Network: 172.16.20.0/24 (Gateway: 172.16.20.1)

Topology Methods & Implementations
Legacy Inter-VLAN Routing: Uses separate physical router interfaces for each VLAN (G0/0 and G0/1). It is easy to learn but lacks scalability due to interface limits.

Router-on-a-Stick (ROAS): Uses a single physical link operating as a trunk line connected to subinterfaces (G0/0.10 and G0/0.20) on the router. It conserves router ports but is limited by shared trunk bandwidth.

Layer 3 Switch Inter-VLAN Routing: Uses Switch Virtual Interfaces (SVIs) and hardware routing directly on a multilayer switch without requiring an external router. This approach offers high performance suited for modern enterprise networks.

Key Learning Objectives
Understand how VLANs isolate traffic and why Layer 3 devices are required for Inter-VLAN communication.

Identify default gateway roles during cross-subnet traffic forwarding.

Compare the design trade-offs, advantages, and deployment scenarios across legacy, trunk-based, and SVI routing methods.