Question on subnetting(counting bits from left to right)

http://imageshack.us/photo/my-images/843/why2not1.jpg/


Why did he count the subnets as 2, 4 , 8, 16 instead of 1, 2 , 4 ,8, 16

I am confused here.
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More about question subnetting counting bits left right
  1. because the first 2 places are X X - don't cares - it's actually is 0, 1, 2, 4, 8....
    -Bruce
  2. I dont understand what you mean Moose.

    His example.

    255.255.254.0

    x.x. 1111111|0 . 00000000


    To find out subnets, (or so I thought) Counting from left to right in the third octet.

    1,2,4,8,16,32,64,128 8 values
    1,1,1,1,1, 1, 1, 1 8 bits

    Shouldn't the subnet masks be 1 + 2 + 4 + 8 + 16 + 32 + 64 for a total of 127?
    Then shouldn't the host be counted from right to left from the 4th octet? going like this.

    end here 512 . 256 128 64 32 16 8 4 2 1 start here

    Doesn't it all look like this? ( I know I'm wrong I'm just showing you how I think so you can tell me why/how I'm wrong)

    x . x . 1 2 4 8 16 32 64 | 512 . 256 128 64 32 16 8 4 2 1
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