Some help with network addressing

Mattitude

Mattitude

Mattitude

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Joined
18 Jul 2007
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England, Berkshire
I need some help with some network addressing. just to clear things im not getting people to do my work for me im simply trying to learn.

i have been given this:

Required number of subnets: 100

Maximum number of hosts/physical segment: 88,000

Network address: 39.0.0.0

Class Address: A

Proposed custom subnets: (need to know how to work this out)

number of subnets supported: (need to know this)

Maximum number of host ID per subnet: (and this)

if anyone could just spend a moment and show me how you would work all this out maybe i will have a better understanding.

Otherwise a link to somewhere you think i would be able to pick this up would be great!
 
sure, i can help. ip addresses are 32 bits numbers split down into four octets. subnetting is all based around powers of two and borrowing bits.

so, you have a class a network of 39.0.0.0/8, and you want 100 networks each with 88000 hosts.

class a networks, by default, provide 8 bits for network addressing and 24 bits for host addressing.

for 100 networks you need to borrow 7 bits from the host portion. 2(7)=128.

you already have 8 bits taken by the major network of 39, plus the 7 bits you have borrowed to provide the 128 sub-networks. this leaves you 17 bits (32-(8+7)) for hosts. 2(17)=131072 hosts per sub-network.

so, your ip address space is going to look like this:

network hosts broadcast
39.0.0.0 39.0.0.1 - 39.1.255.254 39.1.255.255
39.2.0.0 39.2.0.1 - 39.3.255.254 39.3.255.255
39.4.0.0
and so on and so fourth

hope this helps, if you have any more questions just ask.

edit: since my formatting sucks a bit, here is an image of the ip address space from a subnet calculator, obviously this is an extract of the 128 subnets:

 
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