Forouzan

Question

An ISP is granted a block of addresses starting with 190.100.0.0/16 (65,536 addresses). The ISP
needs to distribute these addresses to three groups of customers as follows:
a. The first group has 64 customers; each needs 256 addresses.
b. The second group has 128 customers; each needs 128 addresses.
c. The third group has 128 customers; each needs 64 addresses.
Design the subblocks and find out how many addresses are still available after these allocations

Comments

I have one doubt that if we wanna alocate addresses to 2^14 hosts in group 1, we are here giving 14 bits to host id part but we can only use 2^14-2 addresses because of reserved network and broadcast address. Will it not create problem??

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one more doubt is that whether to first divide into groups and then to customers or directly assign the addresses to customers??

Answer 1

please go through the image, please clear me if I am wrong

Comments

this question is little complicating me,

this is not class B address but CIDR right?

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yeah its CIDR only but since network id bits given are 16 bits, it is just like class B. Anyways answer will not be affected due to this. Its CIDR addressing. Is solution clear to u ??

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ya that one point is bothering me too,

that we can not all n/w ID bit as all 0 and all 1,