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Help with CIDR

This looks a lot like homework... It is very simple using powers of 2 rules. What part is causing you issues?
 
No, it's not exactly homework...I have an exam tomorrow.

Well, I do not understand how to calculate the maximum number of subnets from the given data.
How is it done?? I mean what is the algorithm?? I can do it for Classfull IPs.
 
Generally you assume (for exam purposes) that a 10.x.x.x has a "default" network length of 8 and client length of 24. Subnetting cuts up the those values. So 10.0.0.0/8 -> 10.0.0.0/24 = so the subnet bits are 24-8 (16) so the number of subnets becomes 2^16 or 65536. Client count becomes (2^8)-2 = 254.
 
Your link doesn't work.

64 subnets is 2^6. Seems like there should be more to the question if that is the answer you are getting.

32-26 -> 6
(2^6)-2 is the client count (62)
26-8 = 18, 2^18 = 262144 subnets assuming 10.0.0.0/8 as a base.

If there is previous info like "the original range is 10.10.46.0/24" using the IP 10.10.46.101/26.... The answer shifts to 26-24, 2 bits 2^2 = 4 subnets.
 
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So that tool is telling you max number of subnets that specific network can be broken in to.

10.10.46.64 - 10.10.46.127 could be further broken in to 64 subnets. That is "maximum required subnets" which is useful for IP range assignments. I am not 100% sure that is what your question is asking however.
 
OP, I always start at /24. Working up I double each time, working down half. I have found this the easiest way.

The only caveat is you have to know how the IP addresses in the ranges start and end and also know for MOST tests everything is considered classless and all ranges are valid.
 
Maximum subnets usually also asks for a minimum number of hosts as well so you know how to distribute your bits.

If not your maximum subnets regardless of usefulness is always going to be how many /30 you have (or /31 but that's very special and out of scope for learning CIDR).

Given a /26 as a starting point its going to be 16 x /30 subnets with two useable hosts each as the absolute maximum # of subnets you can create STARTING with a /26.

If you were given 10.x.x.x/26 and it's telling you it's ALREADY subnetted and it wants to know how many subnets were created, and IF no other info is given at all, you are expected to assume the original subnet mask is classful and identify the original subnet mask based on the first octet. In this case it would have originally been a /8 and extended to /26 for total of 256,144 subnets.
 
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Given the context of the OP (exam question), and without knowing the actual questions phrasing, I would assume the correct answer is 4 subnets, with 62 hosts per subnet. I'm on my phone, I'll edit this post with a more detailed explanation for the OP when I get home.
 
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