ip addressing

[gdelgado]

total network addresses by class:

class A = 2 raised to 7 = 128

128 minus 2 = 126 total network addresses for class A

class B = 2 raised to 14 = 16,384

class C = 2 raised to 21 = 2,097,152


************************************************** ***
On pages 97-98 of you ccna study guide 6th ed. for exam 640-802 you explain that class B Addresses have 16,384 unique class B network addresses. This result is not subtracted by 2 as in your explanation of Class A's total network addresses (128-2=126). Same with class C. Does it matter if I say class B has 16,384 network addresses or class B has 16,384 - 2 network addresses?

Thanks for your help

[maer]

The minus 2 substracted for the A-class is unique for the A-class because of the special use of the 0 network (0.0.0.0) usage as a placehodler for default gateway in routing tables and the 127.0.0.0 nework used for loopback.

This has nothing to do with the old -2 for counting subnets and the -2 for amount of hosts.