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CCIE lab exam has been with us for more than 15 years now. In these 15 years, many strategies and many techniques were developed and established themselves as axioms – things you should do when you are taking the lab exam. One of these things is “redraw the diagrams”. In recent months, things in CCIE R&S have changed in such a that may need to force us to rethink that approach. While the main audience of this post are CCIE R&S candidates, other CCIE students may benefit from these words. What happens in R&S, invevitably comes to other tracks, as well!
Challenge of Complex Diagrams
First off, let’s examine a simple network diagram presented below. Let’s work with the assumption that other relevant information, like IP addressing and routing protocols are drawn on the diagram. They are not on this one, but this is just an illustration of the concept anyway.
After 15-20 or so minutes, we may end up having diagram that looks something like this.
Other than wasting time and introducing few mistakes (let me know when you spot them!), what would be the benefit of redrawing the entire diagram, when the one provided is pretty good to begin with? If we continue working with our own hand-drawn diagram, introduced errors may cost us deerly in the lab.
Does this mean we shouldn’t draw our own diagrams in the lab, you may ask? The answer, as with so many things in our wonderful CCIE world is – it depends.
Section Diagrams
Redrawing the entire diagram may be pointless and a waste of time. However, when faced with apparently difficult task, or a troubleshooting ticket, drawing a section of the diagram may be of great help. Let’s play along and take a look at few possible questions related to the network from our diagram.
Ticket 5
- Fix OSPF on routers R12, R19, R20 and R21 so they are able to ping each other’s Loopback0 interfaces.
- Do not modify any configuration on router R30.
What I may do at this point, is quickly redraw the relevant section of the diagram to make things a little bit more clear. Let’s take a look at that.
Since I’m not allowed to touch R30, I’m not even going to draw it. It’s a cloud – a Frame Relay cloud. R12 looks like a hub, with R19, R20 and R21 as spokes. That tells me pretty much what I need to do there…
Let’s look at a little bit more challenging task next.
Redistribution
- RIP is running between R10, R11, R13 and R14.
- EIGRP is running between R13, R14, R15, R16, R17 and R18.
- Interfaces connecting only R13 and R14 run EIGRP.
- Mutually redistribute between all protocols running on R13 and R14.
Again, we can quickly draw a redistribution diagram here that can help us understand what needs to be done. Remember, if you can – use colors. Personally, I have color code for all IGPs. I use red for RIP, green for EIGRP and blue for OSPF. You are, of course, free to use whatever you like! Let’s take a look at the diagram I might make.
In this section diagram, I have everything I need. I know which routers are running RIP, which are running EIGRP and more importantly, I see the redistribution points clearly. Tags that will be used for filtering are also there. I indicated cyan and magenta redistribution directions. I have added descriptive rules in upper corners, indicating what needs to be disallowed and allowed in each direction. In bottom corners I included route-map names for both redistribution directions. This is something I always do when I have anything but very straight-forward redistribution scenario!
This may look confusing at first glance, but after you sit in one of our Instructor Led Classes, it may make much more sense!
Conclusions
Unless you have a really bad diagram in front of you, don’t waste time redrawing entire topology, especially if it’s particularly large. Use diagrams you have provided and if they are missing some information or you may need to analyze specific case in depth, create a section diagram and use that one instead. You are much less likely to make mistakes and you can more easily add the relevant information for the task at hand. This can become very useful when you start end-of-day verification process!
Being able to draw quick section diagrams is very important and this blog barely scratches the surface. You should practice this technique as it will probably save you a lot of time and help prevent mistakes in the lab.
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Marko Milivojevic – CCIE #18427
Senior Technical Instructor – IPexpert
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I couldn’t agree more. When I went through the CCIE R&S 6 years ago I did not draw out the diagrams again. The diagrams were laminated (or covered in plastic) so I used dry eraser markers to mark up the drawings they gave, much quicker.
I also did exactly what you indicated and drew something that required more clarity in my eyes.
As I am taking up the CCIE Security now, I was planning on the same strategy.
I found your errors. =) R10 to R14 and the multi-access between R19, 20, and 21. Can I have a cookie?
With that being said, there is no way I would redraw the TS diagram, there is just way too much on it and many of the devices you won’t even need to touch, so there is no point in redrawing them. As far as redrawing a small section of the diagram, that may help for some of the tickets, but unless you like looking at bad drawings or want to waste your time, I wouldn’t do that either.
I find it useful to redraw the configuration section diagram. It is where I put my notes as I configure tasks, do my redistribution arrows, etc. I see the value in that.
Well spotted, however, you missed some of the subtle ones. I owe you a cookie, still! You see, it’s very easy to overlook things.
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Marko Milivojevic – CCIE #18427
Senior Technical Instructor – IPexpert
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Good post!
After just left the CCIE-room in Brussels a few hours ago I realize that I would not try to do complete redrawing of the entire topology any more. It will just be to cluttered with IP-addresses and all that kind of information that is already provided to you in the work book.
Today in Brussels I removed the main topology drawing from the binder so that I had it available all the time. That is something I can recommend! (I asked the proctor and it was ok…)
Also I realize now that if I had done section drawings like you mention in this blog post I would have much easier to overcome a few tasks. I just wonder why I didnt think of that when There. Instead I tried to use my own “copy” of the overall topology to add more and more info until it was readable.
A note to Jeffrey: I would not recommend writing on the plasted diagrams provided to you. You may end up with problems removing every peace of ink and the my proctor explicitly told us not to do ANY marks in the binder.
The only reason I can see to make my own “whole” diagram is to get a good picture of which units are involved with which technologies and such. But I guess this is more a Security- than a r/s-issue where you allways need to have contreol over where in your topology vpn, nat, acl:s and inspections take place…
but if i’m not mistaken, diagram on CCIE R&S lab right now is presented on screen. so no more handbook.
isn’t that right?
in this case, we have no choice other than redrawing the diagram.
You have the choice, of course! You always has it on the screen. If it’s clear and understandable – there is no need to redraw it, is there? I didn’t!
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Marko Milivojevic – CCIE #18427
Senior Technical Instructor – IPexpert
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I was always fond of colored diagrams. Can we bring our own markers? Or we are getting markers on the exam?
Maybe the right Q would be “must I bring my own markers or these will be waiting for me on the desk” :)
Every time I took the exam in Brussels, I had some color pens available. You may bring colored pens with you, but you may or may not be allowed to use them. If you are not allowed, you may want to offer to leave them in the room after the exam. That may go through.
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Marko Milivojevic – CCIE #18427
Senior Technical Instructor – IPexpert
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Thanks for the advice! As far as using colors, dry erase, etc… is this something they provide for you? I assume you cannot bring anything of your own into the room?
Read my response to Bojan’s question – he asked the exact same thing! :-)