Class A , B, and C question

rogers42

Hi,

I am sure this has been asked infinite times, but here it is again

Why are there (2^7) -2 networks in a class A address ? and why are there (2^24) - 2 hosts per network ?

Why does the same logic not apply to class B (2 ^ 14) and class C (2 ^ 21) networks ?

Thanks

rogers42

dtlokee

Technically there were "reserved" address spaces in class b and c (128.0.0.0, 191.255.0.0, 192.0.0.0 and 223.255.255.0) but that practice has been changed. The problem with the class A reserved ranges is that they were used for other things (loopback and default routing) that makes them impossible to return to the address pool. That is why you subtract 2 for the class A calculation but not from the B or C

http://www.faqs.org/rfcs/rfc3330.html

rogers42

Thanks. It makes sense

rogers42