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bewbies

@173.226.107.x

[CCNA] subnet question

Question is how many subnets and hosts per subnet can you get from the network 172.26.0.0 255.255.255.192?

I already looked at the answer but need to know how it comes about.

by looking at this, this is a class B addressing schema. by looking at the subnet mask, it's looks to be class C.

with this said, i would have answered it Subnets = 4, block size is 64 which can assign 62 usable hosts.

but the real answer is 1024 subnets and 62 hosts.

i always thought we had to follow the C subnet masking and not the IP address scheme.



RyanG1
Premium
join:2002-02-10
San Antonio, TX
kudos:1

Well first off the question doesn't make sense... did you re-word it from perhaps: how many subnets and hosts per subnet from 172.26.0.0 when using a subnet of /26?

but in any case, the class b default subnet is 255.255.0.0 and you are breaking that into 255.255.255.192. So you have 16 bits by default for that classful network and you are adding an additional 10 network bits (subtracting 10 from the host bits). you use the math of 2^n where n equals the network bits you are "Stealing" from the host bits and get:

2^10=1024

Then the hosts is (2^h)-2 so we have 6 host bits left over and we get:
2^6=64-2=62

Hope this helps =)

Ryan
--
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markysharkey
Premium
join:2012-12-20
united kingd
reply to bewbies

The question looks like it came from subnettingquestions.com.
It assumes you have control of the entire 172.26.0.0 subnet and you have decided to subnet it down to a /26.
Look at it the other way. What do I need to do to 172.26.0.0/16 to turn it from a single network in to 1024 subnets with 62 hosts per subnet?
Answer, I need to give it a /26 mask and get counting!