Analysis of the Dynamips for CCNA (or not) Decision

Wendell's analysis of the Surveys and Opinions from Last Post

Last post I generated some discussion about the issue of whether the experienced folk should recommend to newbies that they should use Dynamips et al for CCNA prep, or not at all, or some, and why. Today I'll offer some interpretations of what we came up with, as well as some of my own opinions that I withheld last time for the sake of not influencing the input received from the Cisco Cert Zone community. My goal here is to collect what I see are the biggest decision points - but not all decision points - to help CCNA newbies decide what to do.

First, a few house-keeping items. At least in this blog, when I use the term "Dynamips": the term refers to Dynamips itself, related software like Dynagen and GNS3, and the support web sites scattered around the web. See this link for a blog post with a short intro to the group. Next, Network World likes us bloggers to disclose financial interests, so... I make money when Que sells their new CCENT 640-822 Network Simulator and CCNA 640-802 Network Simulator products. (See for an easy link to those products.) One could argue that Simulators compete with Dynamips as well as the "use real gear" option, so I've mentioned it here. Finally, most everything today is my opinion, although I will list some reasons. But it's just my opinion.

First perspective: For CCNA hands-on skills, Dynamips gives you a shot to develop about 75% of the hands-on skills you need - not a bad percentage in my opinion. Why? First, CCNA can be broken into these categories by percentage of coverage:

  • 25 % - CLI skills that can be learned with routers or switches
  • 25% - Switch-specific features
  • 50% - Router-specific features

For the 25%-ish that's switch centric, you have several strategies. Buy a couple of used switches. Do things with the emulated switch with Dynamips, even though it's not running IOS. Use a Simulator for these topics. Ignore hands-on with switches, but instead spend more time reviewing the switch-based examples in your primary reading materials for your CCNA prep. But the well prepared candidate is probably going to want hands-on with IOS switches, be that with a Sim or with a couple of real Cisco switches.

Second perspective: Danger, danger, Will Robinson - you miss learning about cabling and hardware if you just use Dynamips (or Sims for that matter). Several posts from last time mentioned the danger of prepping for CCNA without even touching real gear. There are benefits to having real gear and cables during your prep. Is the stuff you learn from using real gear a large percentage of what you need to learn for CCNA? Nope. But for getting that job, and having real skills (and not just the cert paper), getting some experience with real gear helps.

Third perspective - The "where do I start" question for CCNAs, at least per my survey, is pretty much a dead tie. One survey from the last post asked what the experienced folks would recommend to CCNA newbies - and it was a 3-way tie (30%-ish each) on the following:

  • Avoid Dynamips until you complete CCNA
  • Get experience on real hardware first, then transition to Dynamips while still working towards CCNA
  • Use Dynamips from the start of your CCNA prep

(The other option, which got roughly 10% of the votes, was to avoid Dynamips for CCENT/ICND1, and use it for CCNA/ICND2 - a curious stat by itself.)

These stats, in the usual unscientific survey, show 2:1 in favor of recommending Dynamips for CCNA prep. They also show a 1:1 ratio of those recommending Dynamips as to whether to use Dynamips first or to instead first get experience with the real gear. Thinking about these numbers from a "where to start" perspective, it's a 2:1 ratio in favor of starting on real gear. In short, I think this numbers put us all over the map on whether a CCNA candidate should use Dynamips not at all, some, or a lot.

Fourth perspective: You can always change your mind, so starting with the free Dynamips option makes some sense. If you overcome the biggest Dynamips hurdle for some - getting an IOS image to use that has the right version, feature set, and works well on your PC - then all it costs is time to test it out.

Fifth perspective: Dynamips will require more time, and maybe leave you feeling a bit lost, as compared with Simulators. Frankly, the whole topic of  Sim software tends to get more reaction than most prep topics - certainly, even a good Sim product has drawbacks. However, Sims have the advantage of built-in lab exercises, built-in lab topologies, and with the labs focusing on the skills needed for the exam. (I am purposefully lopping all Sims into one category for the sake of comparison to Dynamips, but I would imagine a wide range exists within this product arena.)  Are Sims constrained in different ways than the real IOS used on real gear and with Dynamips? Sure. Can you search support sites for Dynamips topologies, and lab exercises? Sure. But Sims typically can be used to quickly focus the time and effort on learning that applies to the exam, using built-in lab exercises, which may get you ready for the exam without wasting as much time.

Sixth perspective: Each option has some compelling features. So, if you choose to primarily use a Sim, or Dynamips, or real gear, they've all got pros/cons. I think most people will end up using at least two of the options, if not all three.

Conclusions: The good news is that CCNA candidates have several reasonable options for getting hands-on skills. The bad news is that choosing the best option(s) isn't so clear cut, and depends quite a bit on the situation and goals of the candidate. So, CCNA newbies out there - what are your thoughts? What issues do you see about your own situation that might influence you towards one option or the other?

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