Chapter 22 Appendix B Converting a Subnet Mask to Binary Code
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The sample subnet mask that we will convert from base ten notation to base two notation is 255.255.0.0.
Key in the value 255.
Click the Bin (Binary) heading. The base two equivalent of 255 will appear as 11111111.
Now let’s look at our base ten subnet mask, 255.255.0.0. We know that 255 converts to 11111111 in base
two. We also know that 0 is 0 regardless of what base it is expressed in.
If you look at the base two line in the above drawing you will notice that there are sixteen 1s in it. The prefix
length of the subnet mask 255.255.0.0. is thus 16.
. ..
2 5 5
0
02 5 5
base ten
base two 11111111 11111111 0 0