MHB Is this a typo in IP networks?

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The discussion centers on a potential typo in an answer key regarding Class C IP addresses. It highlights that Class C addresses consist of a 21-bit network number and an 8-bit local address, leading to confusion over the calculation presented in the answer key, which uses 2^12 instead of the expected 2^21. Participants confirm that the correct formula for the number of Class C addresses should indeed be 2^{21}(2^8-2). The discrepancy raises concerns about the accuracy of the answer key, particularly since the calculated result is significantly smaller than those for Class A and B networks. Overall, the conversation emphasizes the importance of accuracy in educational materials related to IP addressing.
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I think the answer key contains a typo but I want to confirm.

In the internet each network interface of a computer is assigned one or more internet addresses. The nature of these internet addresses is dependent on the networks size. For the internet standard regarding reserved network number each address is a 32-bit string which falls into one of the following three classes...[got first 2 right] class C addresses are used for the smallest networks.These addresses consist of the three-bit string 110 followed by a 21 bit network number and then an eight-bit local address. Once again the local addresses of all 0's or all 1's are excluded. How many different addresses of each class are available on the internet, for this internet standard.

The answer key has [math]2^12(2^8-2)[/math] but where does 12 come from? Shouldn't it be 21 since that's how long the network number is? I'm surprised because the answer key solved it to the integer and it is 3 orders of magnitude smaller than the class A and B networks.
 
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Re: Is this a typo?

find_the_fun said:
I think the answer key contains a typo but I want to confirm.

In the internet each network interface of a computer is assigned one or more internet addresses. The nature of these internet addresses is dependent on the networks size. For the internet standard regarding reserved network number each address is a 32-bit string which falls into one of the following three classes...[got first 2 right] class C addresses are used for the smallest networks.These addresses consist of the three-bit string 110 followed by a 21 bit network number and then an eight-bit local address. Once again the local addresses of all 0's or all 1's are excluded. How many different addresses of each class are available on the internet, for this internet standard.

The answer key has [math]2^12(2^8-2)[/math] but where does 12 come from? Shouldn't it be 21 since that's how long the network number is? I'm surprised because the answer key solved it to the integer and it is 3 orders of magnitude smaller than the class A and B networks.

You're quite right. The number of C class addresses is [math]2^{21}(2^8-2)[/math].
 
find_the_fun said:
The answer key has [math]2^12(2^8-2)[/math]

Just a comment here: $\LaTeX$ only understands one symbol at a time to go into an exponent. If you want more than one symbol to appear in an exponent, then enclose that in curly braces thus: 2^{12}. Result: $2^{12}$. Otherwise, you get what you wrote: $2^12$.
 
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