Question

(a) What is the network number of the IP address 140.100.120.02 if the subnet mask is 255.255.224.0?

(b) Does it make sense to have a subnet mask equal to 255.255.224.7? why or why not?

(c) Suppose an organization needs 8000 IP addresses. How many Class C addresses would be needed? If they were consecutive, describe the CIDR addressing scheme.

Answer 1

AND Subnet mask 10001100. oliooloo olll 1000.00000010 IIIIlllllllllll||10000000000000 10001100 01100100 0110000000000000 network= 140.100.96.0

b)

The mask does not make sense. A mask needs to be a continuous set of bits set to 1. In your example, the mask in binary would be 11111111.11111111.11100000.00000111 which is not possible.

The mask could very well be 255.255.224.0 OR it could be something like: 255.255.255.224 (in this case you would be subnetting a class C network.

c)

) A class C can host 254 hosts. That is all hosts from xxx.xxx.xxx.1 to xxx.xxx.xxx.254
so
it seems like the question is not welll expressed...what the question is probably asking is either how many class C networks you need OR what's the minimum number of IPs that would cover the 8000 clients
if order to address this, you should be using supernetting
you could have 32 separate networks
or a big supernetted network (so everyone can broadcast to everyone)
in that case, you would need a continuous segment of 32 class C networks like for instance 192.168.0.0 to 192.168.31.0
with those networks you could be having a total of 8190 hosts (8192 - 2 addresses, 1 for network address and 1 for broadcast which in this example would be 192.168.0.0 and 192.168.31.255 respectively)