For most of my experiments I use great program GNS3. Recently I switched from legacy 0.8, included in most distributions, to modern branch version 1.3. It was difficult in the beginning to figure out how to install it but once I made it, things became much easier. New features, like auto discovery of IdlePC for any Cisco router saves a lot of time, and ability to move server to another machine is really helpful. Here I would like to describe my lab and task I use it for.