Router on a stick (ROAS)

Almost all networks in the world use Virtual Local Area Networks nowadays. In our lesson about VLANs we have learned a general rule of thumb that is: This means that if we have nodes connected in different VLANs, they most probably are part of different subnets. If we take the topology shown in Figure 1 for example, … Read more

Troubleshooting the vPC Split-Brain Scenario

When faced with a vPC split-brain scenario, swift and methodical troubleshooting is crucial to minimize downtime and restore network integrity.Here are the steps I followed to isolate and resolve the issue: 1.Confirm Split-Brain: Verify if a vPC split-brain condition indeed exists. Check both vPC peer switches for discrepancies in their operational status.2.Analyze Logs: Dive into … Read more

VXLAN (Virtual Extensible LAN)

VXLAN (Virtual Extensible LAN) is a network virtualization technology that extends Layer 2 segments over a Layer 3 network infrastructure. It is commonly used in data center environments to facilitate network segmentation and overlay networks. VXLAN Multi-Site is an extension of VXLAN that allows for the extension of virtualized network segments across multiple data center … Read more

Network Address Translation Lab

Introduction The purpose of this exercise is to learn how to configure NAT for a campus network. We will be setting up NAT on the border router so that the campus private IPv4 address space (172.2X.0.0/16) will be NATed so that devices using that private address space can reach the public Internet. Setting up NAT … Read more


Introduction The purpose of this exercise is to create separate VLANs for different groups of users in each building. In a later exercise we will configure the core router so that each VLAN is using a different IP subnet. This lab is a continuation from the Spanning Tree exercise and the lab setup is identical: … Read more


Lab Objective The focus of this lab is to understand basic VLAN, VTP, DTP and STP implementation and configuration in Cisco IOS Catalyst switches. Lab Topology The lab network topology is illustrated below: Topology Task 1 Enable and configure VTP on the switches illustrated in the topology as follows: DLS1 DLS1(config)#vtp domain SWITCH Changing VTP … Read more