Member Posts: 5 ■□□□□□□□□□
Hi all,
Got a question for you...
How are the first octets of class A, B and C IP addresses represented in binary?
Example:
Class A: 01xxxxxx?
Class B: ........?
Class C: ......?

Thanks for you help.

Take a look at www.techexams.net/technotes/networkplus/tcpipsuite.shtml

It will show you the first octets as well as how to convert from decimal to binary. You must be able to do this from the top of your head for the CCNA exam... give it a shot and give us the answer..
• Member Posts: 5 ■□□□□□□□□□
Got it....

Class A: 0xxxxxxx
Class B: 10xxxxxx
Class C: 110xxxxx

The first octet of a
Class A IP address, can be 1 to 126
Class B IP address, can be 128 to 191
Class C IP address, can be 192 to 223

Listing the binary equivalents of these would result in a long long post

The first octet of a
Class A subnet mask is 255, as in 255.0.0.0
Class B subnet mask is 255, second octet is also 255, as in 255.255.0.0
Class C subnet mask is 255, second and third octet are also 255, as in 255.255.255.0

In binary a class A subnet mask is: 11111111.00000000.00000000.00000000

a class B subnet mask is:
11111111.11111111.00000000.00000000

and class C:
11111111.11111111.11111111.00000000