Answer to Question #152256 in Computer Networks for Ali minhal

Question

Perform the subnetting on the below IP Address and find out the number of networks, network of, first host, last host, and broadcast id of each network.
IP Address:120.0.0.0/20

Answer 1

This is a class B network

$20\ bits\ have\ already\ been\ used\ for\ network,the\ remaining\ i.e\ 32-20=\ 12\ will\ be\ used\ for\ host\ address.$

$The\ total\ number\ of\ hosts\ 2^{12}=4096\ hosts$

$usable \ hosts\ will \ be\ 4096 - 2 = 4094$

Number of networks will be:

$4096 / 256= 16 \ networks$  

$First \ IP\ address\ will \ be \ 120.0.0.1$

$Last \ IP\ address \ will\ be\ 120.0.15.254$

$All\ 16\ of\ the\ Possible\ 20\ \ networks\ \ for\ \ 120.0.x.x$

Network Address       Usable Host Range                               Broadcast Address:

120.0.0.0           120.0.0.1 - 120.0.15.254                                    120.0.15.255

120.0.16.0          120.0.16.1 - 120.0.31.254                                 120.0.31.25

120.0.32.0          120.0.32.1 - 120.0.47.254                                  120.0.47.255

120.0.48.0          120.0.48.1 - 120.0.63.254                                   120.0.63.255

120.0.64.0          120.0.64.1 - 120.0.79.254                                    120.0.79.255

120.0.80.0          120.0.80.1 - 120.0.95.254                                    120.0.95.255

120.0.96.0          120.0.96.1 - 120.0.111.254                                   120.0.111.255

120.0.112.0       120.0.112.1 - 120.0.127.254                                 120.0.127.255

120.0.128.0       120.0.128.1 - 120.0.143.254                                   120.0.143.255

120.0.144.0       120.0.144.1 - 120.0.159.254                                   120.0.159.255

120.0.160.0       120.0.160.1 - 120.0.175.254                                   120.0.175.25

120.0.176.0       120.0.176.1 - 120.0.191.254                                  120.0.191.255

120.0.192.0       120.0.192.1 - 120.0.207.254                                  120.0.207.255

120.0.208.0       120.0.208.1 - 120.0.223.254                                  120.0.223.255

120.0.224.0       120.0.224.1 - 120.0.239.254                                  120.0.239.255

120.0.240.0       120.0.240.1 - 120.0.255.254                                  120.0.255.255