Looking for some good videos that show basic CIDR subnetting calculations

[Oldgamer]

Some of the videos I have come across have not been too good (and a bit confusing). I need something that spells out the best and easiest way to understand calculating the subnetting and CIDR notations.

I am learning this in a community college course, but the instructor is less than par in his teachings. Half my class is failing this, and I am skirting by with a low B at the moment.

If anyone has some good videos that are to the point and give a good basic layout to understanding how this is done I would really appreciate a post with links.

An example of some of my homework:

Network Address 192.10.10.0 Number of needed usable hosts 14
Number of needed subnets 14 I am suppose to show my work.


Thanks!
Oldgamer

 

[ch33zw1z]

It's all in 2^* calculations.

I assume the current subnet is 255.255.255.0 aka 1111111.11111111.11111111.00000000

For the subnets, you start at the left most 0 and move right:

.10000000 = 2^1= 2, subnet is .128, 2 subnets are 0 and 128 (aka 0 and 1) and you have two address ranges 0-127, .128-.254

.11000000 = 2^2 = 4, subnet is 192 (128+64), and you have 4 subnets. .0, .64, .128, .192 (aka .00, .01, .10, .11)

and so on...

check out this link, maybe it will help.

http://www.cisco.com/en/US/tech/tk365/technologies_tech_note09186a00800a67f5.shtml

 

[Oldgamer]

It's all in 2^* calculations.

I assume the current subnet is 255.255.255.0 aka 1111111.11111111.11111111.00000000

For the subnets, you start at the left most 0 and move right:

.10000000 = 2^1= 2, subnet is .128, 2 subnets are 0 and 128 (aka 0 and 1) and you have two address ranges 0-127, .128-.254

.11000000 = 2^2 = 4, subnet is 192 (128+64), and you have 4 subnets. .0, .64, .128, .192 (aka .00, .01, .10, .11)

and so on...

check out this link, maybe it will help.

http://www.cisco.com/en/US/tech/tk365/technologies_tech_note09186a00800a67f5.shtml

Forgot to say thanks!

=)

 

[ch33zw1z]

no problem. we've all been there