Given Subnet Mask = 255.255.255.224
It is a class C network, so 24 MSB belongs to Network, rest 8 belongs to Host.
Subnet Mask is all 1s for subnet and network ID part. 0's for host ID part.
So we get 3 bit for subnet, Total number of subnet = 23 = 8
Now comes the main part.
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According to RFC 950 specification, we have to subtract the subnet with all 0's and all 1s
Therefore, last subnet's network ID will be = 210.15.131. (110 00000)
Last subnet's Directed Broadcast Address = 210.15.131. (110 11111)
Therefore, last host of last subnet = 210.15.131. (110 11110) = 210.15.131.222
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According to RFC 1878 specification, we DON'T have to subtract the subnet with all 0's and all 1s
Therefore, last subnet's network ID will be = 210.15.131. (111 00000)
Last subnet's Directed Broadcast Address = 210.15.131. (111 11111)
Therefore, last host of last subnet = 210.15.131. (111 11110) = 210.15.131.254
Which standard to follow for GATE ?
The new standard, i.e. RFC 1878