lukasz.bromirski.net

aviate, navigate, communicate

CCDE, or how to design a network… or six of them

today I’ve met CCDE exam heads-on in London. it’s a new one at the Expert level, focusing on designing and redesigning of the networks - according to the virtual needs of virtual customers.

after the Networkers CCDE presentation delivered by one of the authors of the CCDE program - Russ White - it’s hard to expect anything different than what they say. it’s very focused on “why”, and “how” is touched only in some generic terms. in other words, CLI-masters will get bored, but you’ll spend a lot of time thinking about subjects like:

  • IGP: OSPF, EIGRP i IS-IS - you need to know those protocols inside-out (seriously!) and have practice in using them (very important!) in designing networks; why you should use this one, what to do to speed things up, how to make it scaleable - this is the way the exam goes;
  • BGP - just like IGP but extended to MPLS; hard obstacle to overcome for people knowing just to configure things up (“you configure mpls ip, and the TE tunnels are configured this way […]“), without knowing “why” - again more “why this way and how it will be better than other options”;
  • QoS - a lot, different perspective, again - “why” not “service-policy output X”;
  • multicast - somewhere between intermediate and advanced knowledge, connected mostly with the applications - from the networking engineer point of view, not software developer;
  • MPLS - how it differentiates from other technologies to tunnel traffic - how it should be implemented, why - a lot of knowledge goes here, and either you have it, or you’ll drown in the materials presented :)

i’m feeling really crushed after it, just like after every each good exam :) a lot of reading, a lot of answering - I did finish after 4,5h out of 8h, but I took additional hour to comment a lot of questions. unfortunately I’ve had a lot of comments, as there were places not described enough from my point of view, and some details were missing. a lot of existing CCDEs was complaining also about it, so maybe I’m not that bad. I unfortunately don’t feel like I passed that, and while it seems my answers were leading the solution into correct direction, “something” kept pinging me that’s not the best way to push forward. on the other hand, while leaving, I saw LCDs of other people on the exam - and after 5,5h some of them were still at 3 scenario out of 6, which clearly shows it’s not that easy.

another suprise was lack of exceptions in the exam center - you have to leave even your watch, and as I was in a lot of pain because of my tooth, I could only take medicine before the exam started, and then during the break - no exceptions. but at least the ladies were helpful :)

i’m going back to reading, CVDs and a lot of practice with designing - with peer discussions. i have a lot of luck to work with people daily meeting challenges I’ve met at the exam. Chris, Peter, Bart - I’m counting on you during the flipchart sessions, to enlight my joyful cluessness :P


Share