Ronnie and I had an interesting conversation with one of our viewers in the Chat Room the other day about preparing for the CCNA/CCENT exams. The conversation focused on the best way to get "seat time" with routers and switches for the exam simulations. I have both asked and answered this question many times myself and have found that there are varied opinions about the subject, but there does seem to be a prevailing attitude as well. My goal then is to give my assessment of the situation from my experience and hopefully others will chime in with their opinions and experiences also.
There are many simulators out there that are designed to give you the best router/switch experience possible and do a really good job of getting you familiar with Cisco IOS. A few stellar examples come to mind immediately (Cisco's Packet Tracer, Boson's NetSim/RouterSim's Network Visualizer) and would be a good investment for anyone studying for their CCNA. They all offer a great experience and are easy to learn to use.
I think one of their greatest strengths is their ability to build a visual topology which makes the logic behind the network design ascertainable at a glance. Another of their strengths is the sheer size of the networks that you can build! Having the ability to fire up 15 routers and 8 switches without your PC screaming for mercy is awesome! And you can build networks very quickly. You can have a decent sized network configured in no time flat. Just drag and drop your needed devices, make your cable connections, configure, salt to taste and serve. Oh, did I mention the pre-built labs? Many simulator vendors offer pre-built labs that you can download. These labs are fantastic for troubleshooting practice as they can be set up to start as broken and you need to assess the situation then make the appropriate fixes.
The downside to using simulators is the fact that they are simulating the IOS environment and don't always support or have all the commands of their physical/emulated/virtual counterparts. Sometimes the output is generic; also sometimes the devices should work and they don't, or don't work when they should.
Router emulators, specifically GNS3, is the router lab of choice for many and for good reason. GNS3 allows you to run the actual Cisco IOS, (or Juniper JunOS) because it is emulating the necessary hardware. This is a great resource for those that want to use labs that require commands/features that their simulated cousins don't offer along with some of the topological/drag&drop benefits. That being said, you need to actually have a legitimate (e.g. legal) copy of a Cisco IOS. Now if you have a physical router you can just get it from there, but otherwise you will need to have a service contract from Cisco. One caveat that I found was the CSR1000V IOS which was downloadable from Cisco.com with a registered guest account. I was then able to get that running in VirtualBox and VMware Fusion. Download here>>>https://software.cisco.com/download/release.html?mdfid=284364978&softwareid=282046477&release=3.9.0aS and enjoy.
The downside to using GNS3 or virtualized routers is that they take up your system resources and they can be less than intuitive to learn to use. Also, they don't really support managed switch IOS (the switches just do generic unmanaged switching). But if you have the system resources and the ability to get beyond the learning curve, then this is the next best thing to having physical equipment with the topological/drag&drop benefits of simulators.
If you do an ebay search of "ccna lab kit" you will be inundated by a flood of results for Cisco switch/router bundles. These kits include actual Cisco routers and switches so that you can get that "hands on" experience that you've been looking for. Some even come with lab books with step-by-step instruction for practice building the types of networks that will be found on the CCNA/CCENT exams.
By far, the greatest benefit from having a physical lab is the actual hands-on experience you will gain. You will be able to say that you have physically plugged in serial cables, console cables, ethernet cables; you have physically installed a WIC, GBIC, and/or Compact Flash memory. In short, you HAVE worked with Cisco equipment, at least to some extent. Obviously you won't have to worry about unsupported commands, canned output, or trying to learn another piece of software before it will all work. You just plug them in and turn them on and get to work. Another benefit would be growth. You can pick up used Cisco equipment for relatively cheap; around $30-$70 USD per device (depending on the devices). This allows you to save and buy new/extra equipment as needed without dropping a large sum all at one time.
Bar far the greatest disadvantage will be the cost of ownership. For a decent physical lab you are going to have to throw down around $300 USD (not accounting for the random deals that can be found to the patient and persistent. I picked up 2 2950 switches, 1 3550 switch, and 2 2821 routers for $340 USD shipped). You will also be paying for the power they consume, which can be extensive depending on the amount of devices you have as well as the time you spend with them all powered on. Also, although Cisco devices are quality, like all physical devices things break. Fans die, power supplies burn out, and ports give up the ghost from time to time and will need to be replaced or repaired. Don't forget cables and WICs.
The last option would be to rent rack access time. This is where pre-wired racks have been set up so you can access them via the internet (telnet/SSH). This is a very cost effective way to get some experience with Cisco IOS and I've seen prices as low as $8 USD for a 4 hour session. That is pretty stinking cheap and all you need to know how to use is telnet or SSH. Also the equipment tends to have the most up-to-date software and hardware, so that's another plus.
The disadvantage of rack rental would be that you have to use your rented time when it is scheduled and you don't get any physical experience with the equipment only remote. Another "issue" is that these rack rentals tend to be CCNP/CCIE oriented.
So what do I think? Which way would I suggest you go? If you have the money then take advantage of all avenues. For those with some money to spend, but not an unlimited budget, I would say that the best course of action would be to build at least a minimalist physical lab (1 Layer2 switch/1 Layer3 switch/1 router) which can be acquired for around $100-$150 USD and then supplement that with GNS3 labs. That is not a huge investment and should be enough for you to prepare. Getting that physical experience is going to be a great return on your investment to go along with that freshly minted CCNA. That being said, I do really like the simulators. I can't say enough good things about Packet Tracer and from what I've seen it is enough to pass the CCNA/CCENT exams, but I would still go with a physical lab if you can swing it.
I hope this helps anyone that is struggling with which way to turn when it comes to getting that practical experience with Cisco routers and switches. Tell us your experience with any/all of these products and methods. We love to hear your input!