ICND1 100-105 Passed Today, about my study method

nole07nole07 Member Posts: 22 ■□□□□□□□□□
Hey All,

I just took my ICND1 test today and I can report that I passed, 860/832. I actually thought I did much better, but nevertheless, a pass is a pass. My test breakdown is below.

Network Fundamentals - 83 %
LAN Switching Fundamentals - 75 %
Routing Fundamentals - 87%
Infrastructure Services - 78%
Infrastructure Maintenance - 75%

So as you can tell, just a middle of the road breakdown. I primarily used Odom's OCG book along with the Chris Bryant Udemy course, and packet tracer. I have been doing networking since around 2004. I was enrolled in the NetAcademy through dual-enrollment at a local community college while i was in high school. After graduating high school I continued at the community college and graduated in 2007 with a degree in Computer Electronics/Networking. I did not use any of my skills for the better part of 10 years so they deteriorated. I was working for a company that supplied atmospheric monitoring equipment and two way radio systems for various industries. Other than setting up some small peer to peer networks my networking studies seemed to be gone....although I can use a spectrum analyzer like no one else lol

Flash forward to 2017, moved to a much bigger city, and got a job as an IT Technician. More of a glorified desktop support tech/network support tech. I had my NET+ prior to getting this job. I got hired on and knocked out my A+ right away. The company is paying for all my certs and during downtime I am free to study. I had been studying for around 5 Months, at least 3-4 hours a day. Probably overkill, but i wanted to make sure i didn't just memorize the stuff.

Subnetting was the biggest thing I was worried about, but after doing it every day for 5 months, it makes so much sense now. First off, don't believe the people who say that "you have to be able to do it in your head on the exam or you're going to fail" Give me a break! I still cant just do it in my head. I'm a very visual person and I have to write out everything. So here's my subnetting chart that worked for me

Write this out on your exam first thing at the top of your sheet. Now basically all you have to do is use this when they give you a problem to solve for example.

What is the subnet address of /29?

Alright first thing I would do is say okay /29 is 5 more than /24.

it goes like this

= each number is one bit and all add up to 32.

Working with /29 you can see that you are working in the last octet, so thats the one you focus on. now from the last octet, count left to right five bits, which gives you 248 with a block size of 8. so your subnets are


Once you find the network that the address they give you fits, you can stop counting . The subnet id is /29.

The same chart is used for calculating how many subnets you can get from a prefix. for example. how many subnets can you create with a /27 mask? Well you always subtract the last classful mask, which is /24 in this case. So that equals 3 network bits you borrowed. Looking at our handy network chart we count over 3 bits and get 224, so a /27 is a subnet mask. now with the 3 bits you borrowed, look at the very bottom and find 3. You can create 8 subnets with a /27 mask. all have a block size of 32.

I hope that some of this helps you all, it may be completely backwards to how you do it, but it makes the most sense to me. It's just following certain steps and counting.

edited:fixed some formatting


  • packetxpacketx Member Posts: 17 ■□□□□□□□□□
    Congratulations !!!
  • nisti2nisti2 Member Posts: 503 ■■■■□□□□□□
    Congratulations! Thanks for sharing!!
    2020 Year goals:
    Already passed: Oracle Cloud, AZ-900
    Taking AZ-104 in December.

    "Certs... is all about IT certs!"
  • hunterthuntert Banned Posts: 231
  • Mr.Robot255Mr.Robot255 Member Posts: 196 ■■■□□□□□□□
    congrats and good score!

    When i was doing the net+ i was struggling with subnets too and that's the same chart i used and it all became so easy.

    on top row u can also write 25-26-27-28-29-30-31-32 for class C's and really saves time when working in the 4th octet a quick glance and u can tell e.g = /27 with a block size of 32

    also Class A 0 =126 B 128-191 C 192-223 D 224-239 E 240 -.....

    all from that one chart it really is good and super fast to jot down before the exam

    i have my icnd1 on the 28th very nervous hope i get to report back with a win :D
  • greg9891greg9891 Member Posts: 1,189 ■■■■■■■□□□
    Upcoming Certs: VCA-DCV 7.0, VCP-DCV 7.0, Oracle Database 1Z0-071, PMP, Server +, CCNP

    Proverbs 6:6-11Go to the ant, you sluggard! Consider her ways and be wise, Which, having no captain, Overseer or ruler, Provides her supplies in the summer, And gathers her food in the harvest. How long will you slumber, O sluggard?
    When will you rise from your sleep? A little sleep, a little slumber, A little folding of the hands to sleep, So shall your poverty come on you like a prowler And your need like an armed man.
  • koz24koz24 Member Posts: 766 ■■■■□□□□□□
  • networkfuzznetworkfuzz Member Posts: 14 ■□□□□□□□□□
  • nole07nole07 Member Posts: 22 ■□□□□□□□□□
    Thank you all, it's such a relief. Now on to ICND2
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