I thought I’d share with you my experience with taking the first steps to be Cisco certified. I didn’t really know what to expect when I started, but hopefully for anyone else considering doing their CCNA (Cisco Certified Network Associate) or CCENT (Cisco Certified Entry Networking Technician).
This is part 1 of 2, as I’ve only gone so far as doing CCENT. It’s half way to becoming a qualified CCNA, and a lot of good fundementals in general networking. To explain further, the first half of the CCNA course is called CCENT 1 (which is just CCENT) and the second half is CCENT 2. You can either do a seperate exam for CCENT 1 & 2, or just a full CCNA exam which contains questions from both courses.
At this point, I’ll quickly mention that if you’ve done your CCNA pre 2007, the course changed and became a LOT harder. So if you see someone’s resume listing CCNA, find out when they did it. Also, Cisco certs are only valid for 3 years unless you do another exam!
So what did I do? I started by getting my employer to pay for me to do a week at DDLS (Dimension Data Learning Services) to study in a classroom environment. I really enjoyed this. The general topics covered were:
- What is a Network?
- OSI 7 layer model
- TCP/UDP basics
- Ethernet – LANs, Switches, Hubs, Routers
- Wireless basics
- Subnetting and Binary
- Cisco basic router configuration
- DHCP router configuration
- Static and dynamic routing
- WAN basics, including NAT
- Management and security of Cisco routers
This is actually a lot to take in for a week. You might look at this list and go ‘yeah I know all that stuff it’s easy!’ But this course really gets down to the whys and hows, not just ‘Do X and Y happens’. You start to understand what’s really involved when you do anything on a network – what data gets put into a packet, how the packet gets from A to B, what changes and stays the same… many people have a general grasp to get by, but you’ll get a proper understanding of how data goes down through the 7 OSI layers and back up again at the other end. What’s the OSI model? Have a quick read here: http://en.wikipedia.org/wiki/OSI_model
Anyway, I got through the week and was keenly learning the whole time. I thought I pretty much knew it all, and was ready to go sit the exam. A few things happened, and it ended up being 2 months before I sat it. A few days before I flicked through the books provided to refresh myself, and confidently went in to take the exam.
Now, there’s a few things about the exam you should know. Firstly, it’s 1 1/2 hours long – and you’ll pretty much need all that time even if you know what you’re doing. Secondly, there’s labs in the exam – so it’s not just multiple choice, but you have to log onto routers and switches, run commands, work out what the answers are and pick the correct choice. Thirdly, you can’t go back once you OK a question. This means time management is really important, as you can’t just fly through once then go through again to re-think your difficult questions, or try and work out answers based on previous questions. You can’t even go back and look at what you answered previously.
Despite all this, I had been told subnetting was a really important part of the exam, and that’s what you should focus on so you can calculate it all in your head. I practised and managed to do this, so walked in confidently…and failed. I was also told, people can do these exams 2-4 times on average, so don’t expect to get it right first time.
I took another week to study, and failed again! I’d learnt everything I wasn’t sure in the exam, but the second time I took it none of those questions even came up, and there was a second bunch of questions I really wasn’t sure of! Even more annoyingly though, I failed by ~1 question.
Third time lucky? Yes. I passed, and was very relieved to get it behind me. I can tell you this is a very difficult exam, and you need to know a huge amount of stuff (both logically and just brain dumps of terminoligies and acronyms) to be able to pass. For example, DHCP – you don’t need to just understand what it’s for, but you may need to know what TCP commands are sent between the server and client, and what order they’re in. You’ll need to have a full understanding of the contents of a TCP packet, and what information changes in it depending where it is on the network. You’ll even need a full understanding of a Cisco switch and how it’s configuration might have security risks, and what you’d need to change, plus remember those commands off the top of your head. You’ll need to convert IP addresses like 192.168.1.44/29 into the network mask 255.255.255.248, and know that the network address is 192.168.1.40 with a broadcast address of 192.168.1.47 leaving you 6 available hosts (I hope that’s right as I worked it out as I went along :) ). What are the channels available on wireless, and which ones should you use and why? What are all the differences between 802.11a, b & g?
So the point I’m trying to make here is there’s a lot to know, but it’s all really good information to have. Once I did the course, I went back to work and really had a much better understanding of what was going on generally, instead of just knowing ‘if I put this here, it works’ I now know why.
You don’t need to go to a classroom though, there’s some great books available, as well as resources like CBT Nuggets which are training videos, very similar to a classroom setup.
I’d recommend this course to anyone who deals with networking, even on a fairly basic level. You’ll need to commit yourself to studying and knowing the contents of the course inside out, but you’ll come out the other end much more knowledgeable and confident of what’s happening on the networks you use.