Little help

[Walkerie]

For some exam revision ive been given this question

Determine the ip addresses that are useable for hosts on subnetwork 200.100.50.0/28

How do i go about working the useable hosts?

 

[V-Spec]

when subnetting the useable hosts is basically the total number of host addresses on the network -2, the first address is the network address and the last address is the broadcast address.
In your example of 200.100.50.0/28 thats a mask of 255.255.255.240 which gives you 4 bits of subnetting which equates to a block of 16 hosts -2 for net and bcast which means in your example you have 14 usable hosts which range from 200.100.50.1 - 14 (.0 is the net and .15 is the bcast, .16 would be the net address of the next block)

hope that helped.

for memory it helps if you memorise all the /xx prefixes for example

/30 (4 hosts 2 usable)
/29 (8 hosts 2 usable)
/28 (16 hosts 2 usable)
/27 (32 hosts 2 usable)
/26 (64 hosts 2 usable)
/25 (128 hosts 2 usable)
/24 (255 hosts 2 usable)
/23 (512 hosts 2 usable)
/22 (1024 hosts 2 usable)

so on, so fourth