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VLSM question

johnnykilo · 2011-12-16 22:25:55

Just studying for a college networks exam at the moment and I have a quick question about VLSM: Are the broadcast and network addresses subtracted from the list of possible subnet addresses? For example if I have 16 hosts, would I use a /28 subnet mask (2^4 = 16) or would I have to use a /27 subnet mask (2^5 = 32 - 2…

16-12-2011 10:25pm

#1
johnnykilo

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Just studying for a college networks exam at the moment and I have a quick question about VLSM: Are the broadcast and network addresses subtracted from the list of possible subnet addresses?

For example if I have 16 hosts, would I use a /28 subnet mask (2^4 = 16) or would I have to use a /27 subnet mask (2^5 = 32 - 2 addresses for the broadcast and network addresses)? Thanks

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#2 17-12-2011 10:56am

PogMoThoin

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The block size is 2^n and available hosts is 2^n -2 (ie it subtracts network and broadcast addresses) from the block size

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