Skip to content

E03 Calculating Subnets

Back to the Course Schedule

Back to the Material: IPv4 Addresses, Subnetting and ARP

Video: Instructions for E03

Example Video: E03 step-by-step, Exercise done in teaching by the teacher during spring 2022

I explain long and in detail, thus long video but, you can't go wrong with this one. Hopefully. Same video description has time tags for E01 - E05.

Subnetting

Student number and parameters of the calculations

Your student number at JAMK/Peppi follows the following model: vvxyzki (e.g. 2092345)

Solution: You can find it in https://peppi.jamk.fi

  1. Login into peppi.jamk.fi
  2. Move your mouse over Studies and press PLP
  3. Select the tab Selecting studies
  4. On the right you can see Opiskelijanumero: <and your student number in peppi>
  5. write down your student number in peppi for this exercise :)
Notice! Older students (account made before 2020 autumn) have to use the following logic
  1. Your student number follows the following model: Letter xyzk (e.g. M4233)
  2. as your student number is a little bit shorter... use i = 3
  3. So with this example the addresses would be
    • 10.42.23.0/24 and
    • 192.168.33.0/24

Notice! Remember IPv4 addresses represented here are in DEC -format

Thus,10.01.01.0/24 would be 10.1.1.0/24

In binary it is important to know how many bits are available, thus sometimes the zeroes before an one are written.

0010 BIN = 2 DEC

The empty zeroes give out an implication of how many bits are possible in electronics or in the variable.

0010 BIN = 000000000002 DEC

The "empty tens/hundreds/... before 2 do not matter"

Use your own student number and form the following subnets: 10.xy.yz.0/24 and 192.168.ki.0/24

With the example student number the result would be: 10.92.23.0/24 and 192.168.45.0/24.

Calculating Networks

Exercise 1

What is the usable (host) address range of 192.168.ki.0/24? What is the broadcast address? What is the subnet address?

Exercise 2

Divide the 192.168.ki.0/24 into smaller subnets with (atleast) 50 hosts in each. Notice! Make as small of a subnet/subnets as you can!

Fill the subnet info column with your information, add more columns if necessary:

Specification Subnet info
Network address
New subnet mask
Number of usable (host) addresses in the subnet
First IP Host address
Last IP Host address
Broadcast address

Exercise 3

Divide the 10.xy.yz.0/24 into smaller subnets:

  • The subnets have to be as small as possible (usable hosts)
  • The subnets must have the capability to support 13 hosts in each of the subnets

Fill the subnet info column with your information:

Specification Subnet info
New subnet mask (decimal or slash format)
Number of usable hosts in the subnet
Network address
First IP Host address
Last IP Host address
Broadcast address

Exercise 4

Divide the last subnet, of from exercise 3, into smaller subnets:

  • The subnets have to be as small as possible (usable hosts)
  • The subnets must have the capability to support 2 hosts in each of the subnets

Fill the subnet info column with your information:

Specification Subnet info
New subnet mask (decimal or slash format)
Number of usable hosts in the subnet
Network address
First IP Host address
Last IP Host address
Broadcast address

Supernetting

Exercise 5

Is subnet 10.xy.yz.0/24 a part of the supernet 10.xy.16.0/20? Write your calculations on paper or do them on the computer. Add the calculations to the documentation (e.g. take a picture of the paper or screenshot).

Exercise 6

Is subnet 10.xy.yz.0/24 a part of supernet 10.0.0.0/8? Write your calculations on paper or do them on the computer. Add the calculations to the documentation (e.g. take a picture of the paper or screenshot).

Looking up addresses

Your own IP addresses

  1. Go to https://www.ripe.net
  2. copy & paste the IP after Your IP address is: to the search box
  3. Investigate and document the results

Internet Registries

Fill the following addresses with your student number: 195.xy.yz.0/24, 43.xy.ki.0/24, 15.ki.xy.0/24 and 100.yz.ki.0/24

Search to whom they are registered to. Search through the RIRs:

Document the results.

What to document of the exercise?

Document in the repository E03.md & /documentation/E03/ -folder:

  • Screenshots, analysis & text while doing
    • Final calculations (on paper or screenshot)
    • Searches from the internet registeries (screenshots)

Back to the Schedule?

Back to the Course Schedule

License

This course and its materials are written by Karo Saharinen and licenced by Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) license.

Creative Commons -licence