Per my previous posts, it has been about 13 years since I completed, the now expired, CCNP, and back in the day, the router simulators were insufficient, at best, and in most cases were worthless. With those experiences burned into my brain, I purchased a couple L3 switches and a couple routers, and I built a small Cisco lab the TV room. I’m a firm believer of “hands on” experience, and this equipment provided a brush up on the physical portion of Cisco gear such as recovering passwords, uploading IOS images and getting the equipment wired up. These activities were a good refresher; however, it became obvious that physically cabling up each hands on practice exercise, which would require the removal of old configs, would get old real quick, so I took the time to check out the GNS3 simulator.
A co-worker, who is studying for his CCIE, told me about GNS3, and I’m glad I listened. GNS3 is free to download, and it is worth the time to read the “Getting Started” guide. The generic download includes many items such as hosts and switching elements; however, all Layer 3 devices require you to download the IOS image from Cisco. I have a CCO account (Cisco website login), so downloading the images is rather easy. If you do not have a CCO account, I’m sure there are ways to download an image from the Internet or possibly a co-worker may have access.
Once the IOS image is downloaded, you create a new router, and point the software to the image, and magically, a router is added to the GNS3 software. I created a basic 2621 router with (3) Fast Ethernet interfaces which supports my needs to the CCNA scenarios. As I progress past the CCNA, other router types may be required.
To create a practice scenario, you just drag and drop the elements needed, and so far, all I needed have been routers and hosts. GNS3 has a VPCS (Virtual PC System) included, and these elements allow you to assign an IP address and ping\traceroute to other elements. This is useful to ensure connectivity across the networks configured in the scenario.
I will add more info about GNS3 as I become more familiar, and if possible, I will add different practice scenarios.