Configuracion de Inter-VLAN Routing (Router on a Stick) - Parte 1

Introduction to VLANs and Switch Configuration

Overview of VLANs

• Jorge introduces the concept of VLANs (Virtual Local Area Networks) and their role in isolating computers within a network.

• He explains the setup of three different VLANs, each assigned to a specific computer with distinct IP addresses for practical demonstration.

Setting Up VLANs

• Each computer is placed in its own VLAN, ensuring they cannot communicate directly with one another despite being on the same switch.

• The first computer is assigned an IP address from the range designated for its VLAN, followed by similar assignments for the other two computers.

Switch Configuration Steps

Assigning Ports to VLANs

• Jorge outlines the process of creating three VLAN configurations on the switch and assigning ports accordingly.

• He details how to configure interfaces on the switch, specifying access modes for each port linked to their respective VLAN.

Verifying Configuration

• After configuring ports as trunk or access, he checks that all settings are correct across all assigned ports.

• Jorge confirms that interfaces are operational after initial configuration adjustments.

Router Interaction with Switches

Understanding Layer 2 Traffic

• Discussion about routers not typically understanding Layer 2 traffic but mentions exceptions where routers can interpret tagged frames.

Creating Subinterfaces

• Jorge explains how to create subinterfaces on a router based on physical interfaces to manage multiple VLAN traffic effectively.

Configuring Encapsulation for Tagged Frames

Setting Up Encapsulation

• He describes how encapsulation allows routers to understand incoming tagged frames from switches using IEEE 802.1Q standards.

Finalizing Router Settings

• Jorge emphasizes enabling proper encapsulation settings so that routers can correctly interpret traffic from switches based on configured tags.

Router Configuration and VLAN Setup

Configuring Sub-Interfaces and Encapsulation

• The configuration begins with assigning a sub-interface for the router, ensuring it matches the VLAN settings configured on the switch.

• A command to show routing is executed to verify encapsulation and tagging, confirming that the setup aligns with VLAN configurations (10, 20, 30).

• The goal is to ensure frames from computers are sent to the router via a trunk link while allowing traffic from multiple VLANs (20, 30).

Verifying Connectivity

• A ping test is conducted from PC1 in VLAN 10 to check connectivity with the default gateway.

• The interface statistics reveal encapsulation details (802.1Q), indicating successful configuration of virtual LAN settings.

Troubleshooting Configuration Issues

• If issues arise, checking assigned VLAN configurations on interfaces can help identify problems; commands like "show interface" provide detailed information.

• Reviewing the routing table shows direct connections between networks without needing additional routing protocols due to directly connected interfaces.

Inter-VLAN Communication

• Pings between computers in different VLANs succeed because each has a corresponding sub-interface on the router for their respective networks.

• When packets are sent between networks, routers utilize their routing tables effectively without requiring complex protocols for communication.

ARP Table Verification

• An ARP command reveals learned IP addresses across sub-interfaces, confirming successful communication among devices within different VLAN setups.