Networking – major network mask and subnet mask

ipnetmasknetworkingsubnet

I've been served with a question to find Major Network Mask and I've only given Host IP address and sub-net mask. I have to find the Major Network Mask using Host IP and sub-net mask.

Another stackoverflow question says both are the same

I've attached screenshots of the question and the steps.

The step describes how to filter host and network information, but you need to find Major Network mask to draw M.D. line.

Step describing drawing M.D line

but in my question, I've only given Host IP and subnet mask.
enter image description here

Best Answer

Major Network Mask is always assigned by the class of the IP addresses used on the network.

If a network has Class A IP Addresses assigned to hosts, Major Network Mask is 255.0.0.0

Class A: 255.0.0.0

Class B: 255.255.0.0

Class C: 255.255.255.0

In my case, IP address 10.210.188.56 is a Class A IP address,so the Major Network Mask is 255.0.0.0

Related Solutions

Networking – Is 225.225.225.128 a Valid Subnet Mask?

Basically a valid subnetmask, when written in binary, has to consist of only consecutive 1's and then 0's, but no intermittent mixing. I.e.:

255.255.255.128 -> 11111111.11111111.11111111.10000000 is valid
255.255.255.0   -> 11111111.11111111.11111111.00000000 is valid
255.255.255.144 -> 11111111.11111111.11111111.10010000 is not valid

Edit: The first bits (the nonzero bits) could also be set to match the network address, the important thing is that if you perform a logical AND operation on an IP with the subnet mask you get the network address.

Host:     10.40.225.164   -> 0000 1010 . 0010 1000 . 1110 0001 . 1010 0100
Subnet M: 255.255.225.128 -> 1111 1111 . 1111 1111 . 1110 0001 . 1000 0000
Network:  10.40.225.128   -> 0000 1010 . 0010 1000 . 1110 0001 . 1000 0000

Networking – Dividing a network into subnets

For a question like that, you start by figuring out how many bits you need to cover that many hosts:

10 hosts, 2^4 = 16 (minus 2 for ID and broadcast). 32-4 = 28, so you're going to use a /28 subnet.

Using your knowledge of how to find IPs in the subnet, you can work backwards from here. You can also list out all the subnets by adding 16, or by working backwards from the IPs again:

192.168.0/24 (given supernet)
  192.168.0/28
  192.168.16/28
  192.168.32/28
  192.168.48/28
  192.168.64/28
  ...

Caveat: Most of these training exercises consider the first and last subnets to be unusable, as well as the first and last IP in each subnet. However, there is a slightly nonstandard method allowing their use.

Best Answer

Related Solutions

Networking – Is 225.225.225.128 a Valid Subnet Mask?

Networking – Dividing a network into subnets

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