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VLSM/SUMMARIZATION

HELLO!! PLEASE I NEED TO UNDERSTAND VARIABLE LENGTH SUBNET MASK AND SUMMARIZATION. PLEASE HELP

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Re: VLSM/SUMMARIZATION

Hi,

VLSM stands for Variable Length Subnet Mask where the subnet design uses more than one mask in the same network which means more than one mask is used for different subnets of a single class A, B, C or a network.

Let’s suppose we want to subnet my 192.168.2.0/24 network in the most efficient way as:

  • One subnet for 12 hosts.
  • One subnet for 44 hosts.
  • One subnet for 2 hosts.
  • One subnet for 24 hosts

Means you have to use only one single subnet 192.168.2.0/24 and calculate or divide different subnets for the above requirement.

When using VLSM, make sure you start with the biggest subnet first or you will have overlapping address space.

Subnet 1: (size of 64)
                                network address: 192.168.2.0
                                broadcast address: 192.168.2.63
Subnet 2: (size of 32)
                                network address: 192.168.2.64
                                broadcast address: 192.168.2.95
Subnet 3: (size of 16)
                                network address: 192.168.2.96
                               broadcast address: 192.168.2.111
Subnet 4: (size of 4)
                                 network address: 192.168.2.112
                                 broadcast address: 192.168.2.115
Because we have different subnet sizes, we need to calculate the subnet mask for each subnet.

https://www.orbit-computer-solutions.com/variable-length-subnet-mask-vlsm/

 

SUMMARIZATION: This is just the opposite of VLSM. We will combine two or more subnets in a single subnet as an example:

We have 192.168.1.0/25 & 192.168.1.128/25. Now I want to summaries those two subnets in a single then it would be 192.168.1.0/24

https://networklessons.com/subnetting/route-summarization

Regards,
Deepak Kumar,
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