How to know when you are ready for the exam
Before you schedule your exam take some time to review the CCNA exam topics. You may surprise yourself and find that you have totally overlooked a topic. Better to realize that you need some additional studying time before you sit down to take the exam :). You should also be able to feel some level of confidence for every exam topic. Take some practice tests too, so you can identify what your weak topics are.
Scheduling the CCNA exam
When you schedule your CCNA exam on the Pearson Vue website, select a day that will allow some pre-exam cramming. I like to take my exams on Mondays so that I have the whole weekend to study before the exam.
Taking the CCNA exam
Make sure that you are well rested and have time to wake up before the exam. Try to eat a decent breakfast so that your brain is ready do binary math :). Get to the testing center 30 minutes early so you can calm yourself with some last minute studying. When you get to the testing center you will have to sign in and have a photo taken. Then they will give you a marker board and walk you back to a testing room. How you use your marking board is key ;). Before you start the exam use some free time to write out things you want to either reference or something you reviewed in the parking lot that you don't want to forget. What really helped me out was using my marker board to write out all of the subnet mask prefix lengths and binary. Especially for prefixes between /16 and /23, those can be hard ones to remember. This can make it really easy to complete subnetting questions quickly. If one thing is going to burn you on the exam if you do not know it well, it is going to be subnetting :(
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