IPv4 VLSM

VLSM(Variable length subnet mask)

VLSM is a process of dividing the network into different network having variable length subnet mask is called VLSM.

Ex: we need public IPs to three offices in country one is the main office in KLD and other two are branches of main office in KLP and KLJ. 124 IPs for KLD, 57 IPs for KLJ, 27 IPs for KLP.

Now we perform VLSM in 200.0.0.0/24 255.255.255.0 network.

200.0.0.00000000/25 mask: 255.255.255.128

Total subnets: 2¹=2. Total host in each subnet: 2⁷-2=126.

Network ID: 200.0.0.0/25 mask: 255.255.255.128 we give it to Kabul.

1^st IP: 200.0.0.1 === last IP: 200.0.0.126 === broadcast IP: 200.0.0.127 (end of Kabul IPs).

N/2 ID: 200.0.0.128/25 === 1^st IP: 200.0.0.129 === last IP: 200.0.0.254 === broadcast IP: 200.0.0.255.

200.0.0.00000000/26 mask: 255.255.255.192

Total subnets: 2²=4. Total host in each subnet: 2⁶-2=62.

Network: 200.0.0.0/26 mask: 255.255.255.192 === 1^st IP: 200.0.0.1 === last IP: 200.0.0.62 === broadcast IP: 200.0.0.63 === N/w ID: 200.0.0.64 === 1^st IP: 200.0.0.65 === last IP: 200.0.0.126 === broadcast IP: 200.0.0.127 === (we give this network to KLJ office) N/W ID: 200.0.0.128 mask: 255.255.255.192 === 1^st IP: 200.0.0.129 === last IP: 200.0.0.190 === broadcast IP: 200.0.0.191 (end of KLJ IPs) === N/W ID: 200.0.0.192 === 1^st IP: 200.0.0.193 === last IP: 200.0.0.254 === broadcast IP: 200.0.0.255.

200.0.0.00000000/27 mask: 255.255.255.224

Total subnets: 2³=8. Total host in each network: 2⁵-2=30.

Network: 200.0.0.0/27 mask: 255.255.255.224 === 1^st IP: 200.0.0.1 === last IP: 200.0.0.30 === broadcast IP: 200.0.0.31 === N/W ID: 200.0.0.32 === 1^st IP: 200.0.0.33 === last IP: 200.0.0.62 === broadcast IP: 200.0.0.63 === N/W ID: 200.0.0.64 === 1^st IP: 200.0.0.65 === last IP: 200.0.0.94 === broadcast IP: 200.0.0.95 === N/W ID: 200.0.0.96 === 1^st IP: 200.0.0.97 === last IP: 200.0.0.126 === broadcast IP: 200.0.0.127 === N/W ID: 200.0.0.128 === 1^st IP: 200.0.0.129 === last IP: 200.0.0.158 === broadcast IP: 200.0.0.159 === N/W ID: 200.0.0.160 === 1^st IP: 200.0.0.161 === last IP: 200.0.0.190 === broadcast IP: 200.0.0.191 === (we give this network ID to KLP office)N/W ID: 200.0.0.192 mask: 255.255.255.224 === 1^st IP: 200.0.0.193 === last IP: 200.0.0.222 === broadcast IP: 200.0.0.223( end of KLP IPs) === N/W ID: 200.0.0.224 === 1^st IP: 200.0.0.254 === last IP: 254 === broadcast IP: 255.

KLD Network ID: 200.0.0.0 mask: 255.255.255.128

KLJ Network ID: 200.0.0.128 mask: 255.255.255.192

KLP Network ID: 200.0.0.192 mask: 255.255.255.224