I am studying subnetting and I am not sure if I've got the hang of fully. Here's a question I've answered with my answers posted below it. I am particularly unsure about Question 4. I'd appreciate some help from people with more experience in this area.
You have been allocated the IP address range 90.103.80/21 for use withing your own network. Suppose you want to be able to accomodate at least 8 subnets within this network and each subnet can accomdate at least 250 individual hosts. Given these constraints answer the following questions:
- How many individual IP address are potentially available for use with the full /21 allocation, assuming there were no subnets created?
- What is the dotted-decimal equivalent of a /21 netmask?
- What subnet mask would be used to provide 8 subnets with at least 250 hosts per subnet as outlined above?
- If we divide up the /21 allocation into 8 subnets, what is the IP address ranges and the broadcast address for the 1st subnet?
- What would change if we instead decided to use 16 subnets?
- We have 11 bits available for the host address so we have 2^11 - 2 = 2046 IP addresses available for use as the first and last addresses in the range are reserved for the subnet address and the broadcast address.
- If we take 3 bits from the host number to use as the subnet number that leaves us with 8 bits left for the host number. Which gives us 2^3 = 8 subnets with 2^8 - 2 = 254 hosts per subnet.
- The IP address range of the first subnet is 18.104.22.168 - 22.214.171.124. The broadcast address is 126.96.36.199.
- If we decided to use 16 subnets the number of hosts per subnet would be 126.
Have I got that right? Also, as a matter of interest what would be the broadcast address of the last (8th) subnet given the above information?