CCNA:- How to Improve Solving Troubleshooting Skills?

Unanswered Question
May 11th, 2007

Hello everyone.

I am studing for CCNA. I bought the CiscoPress Books (Intro and ICND). I also bought the Selftest Exam Engine but it didn?t like me because it is very limited, I got over 90% on all my attempts on this Engine while I got only 80-85% on the Demo Exam of Cisco Press.

But my question is:-

How can I improve my Troubleshooting skills?

Is this objective included on any of the Simulators Software Boson or Sybex or they only do some labs? What would be better?.

Thank you.

I have this problem too.
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scottmac Fri, 05/11/2007 - 19:51

Troubleshooting is all about comparing what you see with what you *know* ought to be there (or *not* be there).

By understanding how the protocol or mechanism works, you should be able to predict what you should see for any given set of data (if I input this, I should get this out). At the least, you get a "feel" for what looks right ... even a ballpark guess can get you looking in the right direction ... but you have to be in teh right ballpark.

The point being: this is the difference between memorization and understanding. If you are just trying to remember the answers, Cisco can toss you a curveball, and you sit there stumped.

If you understand the process or mechanism, there is no trick they can play on you .... "X" in gives you "Y" out, no matter how they phrase it.

The trick is to know it well enough to see the issue(s) within the timeframe allowed for the test.

Having hands-on, whether it's real equipment or a SIM (personally, I'm a Boson fan), seeing the problems and working to correct them give you that "Oh, I've seen this before" type insight that tends to make a better memory impression ... that's what experience is all about ... after you've seen a scenario a few times, you tend to remember what it looks like when it pops up out of the blue.

FWIW, that's my two cents.

Good Luck


hecg Sat, 05/12/2007 - 05:54

Thank you very nuch, Scott. Your answer is much more than two cents.

I got the Selftest Engine software just in order to practice answering some questions but it is not for learning, even I do not know if it is what you call "braindump".

For my own preparation on all the things I had to learn, I always had tried to understand the all procedures or mechanisms behind the concepts becuase it helps me to memorize them, so I am entirely agree with you, but I did not know how to improve my skills in troubleshooting.

Now I could know as because you very kindly are suggesting me that I use the simulator.

I bought and I studied by the two CiscoPress Books (Intro and ICND) and they came with a Demo of Boson Simulator and a few labs, but those labs are not guided in troubleshooting, so does the Full version of Boson Simulator guide to troubleshoot?

Thanks again.


scottmac Sat, 05/12/2007 - 06:40

I don't believe they have anything specific to troubleshooting, no.

The simulators commonly available, including Boson, are not an all-encompassing SIM ... those cost tens of thousands of dollars. They are (generally) set up to simulate problems caused by common mis-configuration.

Some SIMS, like Boson, are guided lab exercises ... the SIMs work very well within the context of the exercises they present, and some of common mistakes made. They are not (usually) useful for "free-style" setups much beyond the type of scenarios presented in their Labs.

Now, what you can do(and I believe this is helpful in the context of the test simulations), is to do the Lab exercise, make it work as suggested, then break it ... put in a wrong value (like a bad subnet mask), see what effect it has, and what the output is at the various stages of the setup, how did the routing tables change, do you get one-way paths ...

Many folks get the SIMs and either ignore the included exercises or zip right through them without paying much attention to the lesson.

It's not a race. Take your time, think about what they are trying to show you. Change some values and try to predict what the effect will be ... if what happens is not what you predicted, then figure out why.

There is no magic to troubleshooting. Be methodical. For networking, the OSI model is a very useful structure for guidance. Start at Layer 1 (is it plugged in? do I have physical connectivity?), move to Layer two (right encapsulation? Correct Speed & Duplex?, corect DLCI & LMI?), then layer three (correct IP address & mask?, routing / forwarding tables? ) ... and so on up the layers. That is why the OSI model is usually a key topic for new networkers; it is the structure that networking is built on.

For physical troubleshooting, there are a variety of philosophies (like anything else). They generally fall into "top down" or "bottom up" approaches ... but essentially it boils down to: "Start at one end (top or bottom, left or right) and work your way to the other end."

If you know how the system operates (whether the system is software, hardware, logical or physical) you should be able predict what happens on the other side ("I have this input, this {thing} does this, I should have this output on the other side"). You have to stay with your chosen method ... one step at a time, until you don't get what oughta be there ... that's (usually) where the problem is.

Sorry for the rambling; "troubleshooting" is a huge topic and not easily summarized.

Keep working with it, practice, break some things ... see what it looks like when it's not working; the more you see and do the better.

Good Luck


hecg Sat, 05/12/2007 - 07:22

Thank you very much and I apologize for bothering you again.

I have always worked in Nets and me I also know that to solve troubleshooting is achieved looking for all the possible causes and to go isolating them or separating them until giving with the error. Although, many times, like in the Medicine we help ourselves applying a sixth sense.

It is very good and intelligent your suggestion (and I thank it to you) of trying to generate some flaws in the Simulator and although I know that it is almost impossible to try to embrace all the possible flaws that can be caused, anyway, do you know some product that can help me or guide me a little in in this type of experiments trying to solve problems?.

Sorry for the question again, If I insist you so much in something that guide me it is because I don't have a lot of time and I have to get this certification asap

Sorry, It is Saturday and I am making you lose your resting time.

Thanks again.

Best regards.


pciaccio Sat, 05/12/2007 - 15:58

There is no substitution to real life experience. You need to burn in order to learn. You never know what problems you will encounter in real life production networks. What anomolies you will see and how to troubleshoot them unless you see them for yourself. No simulater is going to provide this experience to you. That is why the CCNA and all other certification exams are so tough. They want to know what you know from your real life experience and not just from a book. It is the experienced professional that deserves the certification if they can pass the exams...It is the experienced professional that companies value because of their experience. I knew many people that passed their CCNA exams but could not even fix their pants...It is a shame but a true reality...

cisco steps Sun, 05/13/2007 - 10:59


I just want to add, if you can invest on cisco lab that will take you all the way to ccnp that will be great invinstment, you always can get your money back..well you we loose some, but let say you sell your lad and you lost $200, you gain lot more then that and @ your own time. from my experience just putting the rack and cables togather was fun for me, it give the boost if you undersatand what I am trying to say, I am no longer behind the door and looking from the key nob. trying to see if anyone there...


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