$(14\%)$ Suppose CUHK is allocated a block of IP address: $10\mathrm{.}23\mathrm{.}16\mathrm{.}0/20.$ Based on your knowledge of IP addressing, answer the following questions.

a$)$ How many hosts at maximum can CUHK supply with public IP addresses? $(2\%)$

b$)$ There are $9$ colleges that CUHK needs to distribute the IP addresses. Suppose the IP address demand from each college is $300.$ What will be the block of IP addresses allocated to each college? $(5\%)$

c$)$ Suppose IE department is allocated with the block $10\mathrm{.}23\mathrm{.}34\mathrm{.}0/23.$ Write out the network address of the IE subnet in binary form. Suppose the CUHK IE gateway receives packets going to destinations: $10\mathrm{.}23\mathrm{.}28\mathrm{.}1,10\mathrm{.}23\mathrm{.}34\mathrm{.}1,$ and $10\mathrm{.}23\mathrm{.}35\mathrm{.}1.$ Write these IP addresses out in binary form. Should the gateway forward them all into the CUHK IE subnet? If not, which one$($s$)$ should be blocked? Can you list all IP addresses allowed in the CUHK IE subnet $($

xxx$.$xxx$.$xxx$.$xxx $x.x.x.x)(5\%)$

d$)$ If the IE subnet is growing so fast and exceeding the number of hosts allowed, what can the IE network administrator do to cope with the problem? $(2\%)$