Dynamips – Would You Recommend it to a New CCNA Candidate? (Survey)

While potentially useful as an end to itself, my previous post - essentially an overview of the use of Dynamips for Cisco cert prep - was really a set-up to discuss today's topic. Today's topic is meant for two groups: those new to CCNA, and those that have gone beyond CCNA and have also used Dynamips. For newbies, the question is, should I use Dynamips as my primary hands-on learning tool for CCNA prep? And for oldies, the question is, what advice would you give the CCNA newbie regarding whether to use Dynamips or not, and under what circumstances?

More than a few folks out there begin thinking about CCNA and take a look at what tools are needed - and they eventually will ask the question "should I use Dynamips as my primary hands-on learning tool for CCNA prep?" Other options exist: real gear, Simulators, taking classes, renting gear, watching videos, and I'm sure others that I can't think of. Today I'm ignoring the other options, and focusing on the tradeoffs and advice we collectively might give when asked the question by the potential CCNA candidate.

First off, Dynamips is free, and it runs real router IOS. (see last post for a quick background discussion). With a laptop, it goes with you; with a desktop, you can remotely access it. You can build virtual routers with different hardware, and cable with different topologies, and save those, for quick transition from one topology to another. All very cool to the geek (I say that with utmost respect!) and very useful. In short, there are many compelling reasons to use it. But, if I'm bothering to ask whether it's the best tool for a newbie to CCNA to learn with, then there must be some reasons why it may not be best for newbies to CCNA, so the rest of this blog post, we'll look at the potential reasons to not choose to use Dynamips, at least for CCNA.

I'd categorize the issues into two main categories: skill of the new CCNA candidate, and more general issues that are the same for most anyone. First, the issues that vary depending on the new CCNA candidate's skill level are:

• Familiarity with real Cisco hardware and cabling
• Cisco CLI skills
• Familiarity with Telnet/SSH client software
• General PC skills (Windows and/or Linux)
• Familiarity with Cisco IOS versions and feature sets

Generally speaking, the less skill with any of the above, the more challenging it might to be to use Dynamips. A lack of skills in any of these areas can be overcome, some simply, some through some searching and hard work.  For example, Cisco router IOS have different versions, with later versions adding functions and fixing earlier code problems. IOS feature sets define broad sets of functions inside an IOS. A pre-CCNA probably does not know anything about IOS versions and feature sets - in fact, you don't have to learn much about them to pass CCNA. To use Dynamips well, the user benefits from a deeper knowledge of such details and how to use the primary tool to learn about those details (www.cisco.com/go/fn, the Cisco feature navigator). Is a lack of such knowledge a show stopper for using Dynamips for CCNA prep? Not at all. Is a lack of knowledge in this area an impact to how long it takes to make good use of Dynamips, and how effective that time might be? Definitely. So, for you experienced folks out there who're interested in answering the surveys or making comments, I'm not saying the degree to which the above example matters, just that it does have an impact - and I'm trying to collect more than just my opinion on it.

Finishing off the above list... I think the familiarity with Cisco hardware and cabling makes some difference in how quickly someone learns to use Dynamips effectively. Certainly CLI skills (or lack thereof) impacts the user of Dynamips a little, but for CCNA, that's one of the big things to learn for the tests. Personally, I think someone with a lack of CLI could just learn those skills while using Dynamips. You do need to setup a telnet or SSH client for Dynamips, so again, it's not an issue of whether someone who never used telnet/ssh can't learn how to use them, but rather that it just takes more time to get productive with Dynamips. And of course, the better the OS skills, the easier it might be to get the Dynamips and related software installed and working.

The other general category of issues, unrelated to each person's skill set:

• Dynamips performance on their available PC
• Linux vs. Windows on available PC
• Availability of IOS images
• Availability of free mentoring

I talked about the IOS image availability in the previous post, so I'll ignore it here, other than to say it may be the largest practical issue when choosing to use Dynamips or not. Dynamips does require some tuning to make the IOS images run more efficiently on your PC. Anecdotally, the first time I played with Dynamips, it took me an hour to go from "working but unusable due to performance" to "working and usable", and another hour to tune enough to get to "working and usable and smiling user". That result does depend on the person's computer skills (I'd call mine average for a network engineer, for perspective). It also depends on your PC and your OS. As I mentioned before, I'm not a Dynamips expert, but have used it, but the word on the net is that Dynamips will run better under Linux than under Microsoft OS's. Finally, the ability to get some help from someone you trust (online sources are fine here as well) can help immensely.

So, to the surveys. You can make any written comments, but here's a couple of survey questions just to quantify the discussion a bit. First, imagine the following CCNA candidate, who might be typical of a college-aged person who's not worked full time in an IT job before:

• Never used IOS CLI yet
• No IOS/feature set knowledge yet
• Never seen/cabled Cisco gear
• Grew up with a PC at home (solid user-level PC skills)
• Has not used Telnet/SSH clients
• Very comfortable with social networking, forums (for mentoring)
• Was given a CD with 2 IOS images (both for 2610's), but no other direct IOS access
• Has dual-boot capability for XP and Linux on their laptop for school

Clearly, many other variations on this theme exist, but for this candidate, what's your personal recommendation?

Next survey: Of those issues I raised, pick the TWO issues that you think are the biggest challenges for the pre-CCNA candidate for using Dynamips as their primary hands-on prep tool. My goal with this one is to see if there are particular triggers that identify what types of candidates might have the most difficulty, and by implication, which issues may not be as big a deal. (Otherwise, I've have to make up dozens of example CCNA candidates, and ask about all those!) Note that in the one item about IOS images, I'm trying to zero in on the issue of whether you really need the ability to download any IOS version or feature set, or whether just having an IOS image is enough. Clearly, having no IOS images is a complete show-stopper for using Dynamips.

Thanks group. Click and comment away!

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