Free Subnetting Lesson - 1

Subnetting Lesson 1

WOW, well done on jumping in and learning about subnetting.  OK, I admit
that it probably won't be as exciting as the next Harry Potter book or
hold more intrigue as the next Dan Brown novel but those books won't
help you with your job either and learning subnetting (I bet) surely
will.

Lesson 1 is very easy, you are going to learn to write the subnetting
cheat chart out by hand.  Some people are caught short in exams and
interview because they have only used the printed version of the chart.

You want to be able to write it out by hand in case you have to quickly
troubleshoot a network problem at work or in an exam.  Here is how you
do it.

Grab a sheet of paper.  In the top right hand of it write the number
1.  To the left of that double it to 2, to the left of that double it
to the number 4.  Keep doubling the numbers until you have done it
eight times and have reached the number 128.  Your top row should now
look like this:

128 64 32 16 8 4 2 1

This is a binary octet and you can use it to write out any number
which can be used as an IP address.  Next, just to the left of the
number 128 and down a little bit write a column of numbers starting
with 128.  Next add 64 to get 192 and put that underneath.  Next
add 64 to get 224 and write that.  Keep going adding a number from
the first row.  It should look like this:

128
192
224
240
248
252
254
255

These are all your possible subnet mask values.  You can see that
we arrived at them by adding the numbers from the top row together.

The last set of numbers we use for network design questions.  Under
the last column leave a gap and just write out some powers of two.
Take the number 2 and net to it write (-2).  Then just keep doubling
the numbers a few times.

2(-2)
4
8
16
32
64
128
256
and so on.

That is all for today.  To look at the finished product please visit
the link below.  We will run through how to use the chart tomorrow.
So please, between now and then write the chart out several times so
that you can do it from memory.  If you get stuck just put a number
one in the top right of the paper and double it to the left.

http://www.subnetting-secrets.com/subnetting_cheet_sheet.html

There is a lot more detail on subnetting in the full version of the books along with the videos:

http://www.subnetting-secrets.com/buy_subnetting_secrets.html

or it is given away to all members of http://www.howtonetwork.net which

is a unique Cisco CCNA online training site.

Until tomorrow.
 

  Or call us on the toll free numbers at the top.