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I am currently studying towards earning the CCNA Certification. My question is how is it that the number of hosts possible is 224 for a class A IP Address. I am clear on one octet being used for the network id and the remaining 3 octets being used for the host id. How is the number 224 determined?

• Member Posts: 2,378 ■■■■□□□□□□
when you say 224 do you mean 2 to the 24th power? (eg 2^24) The actual formula would be 2^24 - 2 = 16777214 hosts on a single class A network
The only easy day was yesterday!
• Member Posts: 9 ■□□□□□□□□□
The host id for class A is made of the last three octets, or the remaining 24 bits, so the number of hosts possible for each network id of class A is 224. Where does or how is that number of 224 determined. I am clear on the 2 to the 24th power representing the higher number of 16,777,214. I did not mean 2 to the 24th power.
• Member Posts: 4,884 ■■■□□□□□□□
Shohola wrote:
The host id for class A is made of the last three octets, or the remaining 24 bits, so the number of hosts possible for each network id of class A is 224.
That is simply incorrect. How or where did you get that figure?

Just so we are perfectly clear, the maximum possible number of hosts on a class A network is 2^24 which is 16777216 hosts.

It looks to me like you are adding together the first 3 bits of an octet 128+64+32=224. That has nothing at all to do with the number of hosts on a class A network.
All things are possible, only believe.
• Member Posts: 9 ■□□□□□□□□□
Thanks for the clarification, I am studying for the CCNA, thru a CBT which I purchased and downloaded from www.semsim.com. I am a Devry Technical Institute graduate of the Electronics Technician Program from 1988 and am very knowledgeable with Analog and Digital Technology, and have recently started to pursue this CCNA course which I am handling so far. Sometimes I just run into a roadblock and need a little help, and thank god for the techexams.net website, at least I can post questions and hopefully get some good responses from others like yourself, Thanks.
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Your welcome. Keep up the good work. And after reading my post over again I am afraid it sounded a little terse - my apologies on that. Hope you didn't take it as unfriendly.
All things are possible, only believe.
• Member Posts: 9 ■□□□□□□□□□
No, not at all. I see you have already earned the CCNA, as well as others. Congratulations, that is quite an accomplishment. I bet i'll be communicating with you again sometime on the forum, i'll probably have more questions as i progress thru the course. Take it easy!