Why we need to use “and operation” to get network ID? For example, 192.168.100.100/24 11000000.10101000.01100100.01100100 Why we don't get the network ID by scanning this IP address from left to right for 24 bits to get the network ID,but use "and operation" to get it? 11000000.10101000.01100100.01100100 11111111.11111111.11111111.00000000 11000000.10101000.01100100.00000000 How can a computer know those bolded 00 are belong to network ID,but not belong to Host ID?