Just a Couple of Random Thoughts Rattling Around Upstairs
I’m sure we all wonder at times why certain ideas pop into out heads. Wrting a blog, in some ways, gives you a place to write those ideas, rather than just letting them rattle around. Today I’ll toss out two such random rattlings that actually have something to do with Cisco certs one about tactics for troubleshooting problems on Cisco exams, and another for CLI prep time for those same exams.
Rattling Idea 1: Going from down/down to Root Cause
The first idea has to do with how people troubleshoot problems on Cisco exams. It’s exam day – ICND1, or ICND2/CCNA, or CCNP SWITCH, CCNP TSHOOT, or even CCIE – and at some point, in some question, you see a switch interface that’s down. What does that tell you? What could cause that state? What configuration is related to each root cause that could cause an interface to be down?
First, let me define terms. On a switch, if you issue a show interfaces command, you see two status codes; if you use the show interfaces status command, you see a single status code. When the status of the show interfaces output lists down/down (shorthand to mean that both status values are “down”), tWhen the show interfaces status command should also list a matching state of “notconnected”. But can you make a list of all things that cause this status? With confidence? And feel like it’s comprehensive?
Why in the world is this one rattling around up there in my noggin? Well, the sequence of learning all the facts that impact an interface’s status is somewhat opposite to answering the question “what causes this interface to be not connect?”. First you learn what an interface is. Then in CCENT, you learn a few things that might impact the status, like having no cable, configuring a shutdown command, and the like. ICND2 adds a few more reasons, or at least potential reasons. CCNP SWITCH adds more. But which of those put the interface into a down/down state?
Regardless of the exam, or the real job, you sit there with an interface in down/down aka notconnect state, and wonder, what could cause this? So you need to reverse engineer all those reasons, which is a bit backwards from how you first learned all those potential causes.
To end this one for today at least, let me suggest an exercise: make your own list, and don’t refer to your notes. Post your list here, post individual ideas here, etc. Together, let’s make a list of all reasons for down/down on a switch.
I’ll follow up on this one somewhere down the line in the coming weeks, and see what our combined list looks like. Also note whether you think a particular feature is in the scope of CCENT, CCNA, CCNP, or CCIE topic scope, at least in your opinion. Also, if it helps, use SW1 as the name dow a switch. F0/1 connects to a PC, F0/2 to a hub, F0/3 to another switch (SW3), and F0/4 to a router (R1). In case you want to describe something.
Rattling Idea 2: How Much Time to Prep in Lab?
Recently, someone at Cisco Press asked me how much time I think it would take to do all 250 labs in the Pearson Network Simulator. I think doing all those labs, at a speed that allows learning (rather than just trying to finish quickly), takes quite a while. In fact, doing all the labs at a reasonable speed is probably overkill for exam prep, but we hear that the Sim’s labs have been very effective for exam prep, which of course was the idea that was the idea in the first place. But that’s not the point. What’s really rattling around in my head is this: how much CLI time are people doing in preparation for various exams?
So let me define some parameters. Clearly, buying a Sim takes the least overhead in terms of getting it and doing commands on the CLI, at least as compared to getting real gear and using Dynamips. However, I don’t care about that extra time. Just think about time doing commands on the CLI. How much time do you spend doing commands on the CLI for the purpose of prepping for CCNA, no matter whether you used real gear, Dynamips, or a simulator? I don’t think I’ve ever asked the community at large, so post away and give me your thoughts. How much time should people devote to CLI learning?
And as you might guess… it’s poll time! I’ve set up two polls. The first is for CCNA, so if you took (or are taking) the two exam path, think about how much time you spent on both. CLI time, to prep, until passing CCNA. The second survey asks for the net additional time for CCNP ROUTE only. I constrained it to ROUTE just so it’s a little easier to estimate. I know practically no one would have tracked their time, but give it a swag, and let’s see what the results look like.
That’s it! Later…
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