[ Log On ]
  • Home
  • Tst
  • Cha
  • Enc
  • Code
  • IP
  • Fun
  • Sub
  • DigF
  • Cis
  • Com
  • Db
  • About
  • Netsim

Subnetting

[Back] This pages outlines some subnetting material.

Calculators

  • Your details. IP. This shows your browser details.
  • IP address analyser. IP. This involves converting an IP address to the host and network part of the address.
  • IP subnet analyser. IP subnets. This involves converting an IP address to the host and network part of the address.
  • Max subnets. Max subnets. This involves converting an IP address to the host and network part of the address.
  • Route summarization. Summarization. This involves converting an IP address to the host and network part of the address.

IP Challenges

  • IP Test 1. IP Test. IP Classification test. This is a simple test which generates a range of IP addresses, and you must determine the IP address classification. IP Subnet Challenge 1 Demo
  • IP Test 2. IP Test. IP Classification test Part 2. This test provides an address classification, and the user must find the addresses which are of this classification. IP Subnet Challenge 2 Demo
  • IP Test 3. IP Test. IP Classification test Part 3. This test provides an address classification, where the network part of the address is determined. IP Subnet Challenge 3 Demo

Route Summarization

Route Summarization is one of the more challenging areas of networking. The key thing is to determine the bits that are common in the bit sequences (starting from the left-hand side). All the examples given here are included on this Web page.

Example 1

For example:

172.16.128.0-172.16.159.255

gives:

10101100.00010000.10000000.00000000 (172.16.128.0)
10101100.00010000.10000001.00000000 (172.16.129.0)
10101100.00010000.10000010.00000000 (172.16.130.0)
... 
10101100.00010000.10011111.11111111 (172.16.159.255)

where the common part is:

10101100.00010000.100

where 10101100 is 172
where 00010000 is 16
where 100xxxxx is 128

which gives:

172.16.128.0

and since we using 19 bits (8+8+3) to give a route summarization of:

172.16.128.0/19

Example 2

For example: 192.168.98.0 192.168.99.0 192.168.100.0 192.168.101.0 192.168.102.0 192.168.105.0 we get:

11000000.10101000.01100010.00000000 (192.168.98.0)
11000000.10101000.01100011.00000000 (192.168.99.0)
11000000.10101000.01100100.00000000 (192.168.100.0)
11000000.10101000.01100101.00000000 (192.168.101.0)
11000000.10101000.01100110.00000000 (192.168.102.0)
11000000.10101000.01101001.00000000 (192.168.105.0)

We can see that the first part is common to all the bit sequences:

11000000.10101000.0110

where 1100 0000 is 192
where 1010 1000 is 168
where 0110 0xxx is 96

giving: 192.168.96.0

and we have 20 bits shared, thus the result is 192.168.96.0/20

Example 3

In this example we have:

172.1.4.0 172.1.4.128 172.1.5.0 172.1.6.0 172.1.7.0

which gives:

10101100.00000001.00000100.00000000 (172.1.4.0)
10101100.00000001.00000100.10000000 (172.1.4.128)
10101100.00000001.00000101.00000000 (172.1.5.0)
10101100.00000001.00000110.00000000 (172.1.6.0)
10101100.00000001.00000111.00000000 (172.1.7.0)

which gives a common part of:

10101100.00000001.000001

where 10101100 is 174
where 00000001 is 1
where 000001xx is 4

which gives 174.1.4.0

and we have used 22 common bits to give:

172.1.4.0/22

Example 4

For example:

100.16.0.0 100.17.0.0 100.18.0.0 100.19.0.0

which gives:

01100100.00010000.00000000.00000000 (100.16.0.0)
01100100.00010001.00000000.00000000 (100.17.0.0)
01100100.00010010.00000000.00000000 (100.18.0.0)
01100100.00010011.00000000.00000000 (100.19.0.0)

The common part is:

01100100.000100

Where 01100100 is 100
Where 000100xx is 16

to give: 100.16.0.0/14

Subnetting Challenges

  • Subnet Test 1. Subnet Test. Subnet Test.
  • Subnet Test 2. Subnet Test. Subnet bits. [Demo solution]
  • Subnet Test 3. Subnet Test. Find the nth usable subnet. This test involves finding the nth usable subnet.
  • Subnet Test 4. Subnet Test. Maximum subnets. This is a test page to determine the maximum number of subnets and hosts/subnet for IP classed addressing.
  • Subnet Test 5. Subnet Test. Maximum host/subnet. This is a test page to determine the maximum number of hosts per subnet.
  • Subnet Test 6. Subnet Test. Determine the required subnet mask for a given number of subnets. This is a test page to determine the required subnet mask for a given number of subnets and a given IP address classification.
  • Subnet Test 7. Subnet Test. Determine the required subnet mask for a given number of host/subnet. This is a test page to determine the required subnet mask for a given number of hosts per subnet and a given IP address classification.
  • Subnet Test 8. Subnet Test. Route summarization. This involves a calculation on route summarization.
  • Subnet Test 9. Subnet Test. Binary to IP.
  • Subnet Test 10. Subnet Test. Hex to IP.
  • Subnet Test 13. Subnet Test. Wild card mask network bits. Find the number of bits in the network part of the wild card mask. [Demo solution]
  • Subnet Test 14. Subnet Test. Wild card mask host bits. Find the number of bits in the host part of the wild card mask. [Demo solution]
  • Subnet Test 15. Subnet Test. Wild card mask ... find the network address. Find the network for the wild card mask. [Demo solution]
  • Subnet Test 16. Subnet Test. Find a matching IP address for a network and wild card mask. Find the IP for a network and a wild card mask.
  • Subnet Test 17. Subnet Test. Find an address which is on a given network Find an IP address on a network, for a given network address and subnet mask.
  • Subnet Test 18. Subnet Test. Find an IP address on the same network. Find an IP address on the same subnet.
  • Subnet Test 19. Subnet Test. Find subnet. Convert subnet mask.
  • Megatest. Subnet Test. Challenging test for subnets.
Tweet