ip子网划分及学习（IP subnet partition and learning）.docVIP

ip子网划分及学习（IP subnet partition and learning） Subnet address: host address and netmask and arithmetic Broadcast address: subnet address and netmask XOR Subnet address: subnet address available IP +1 to broadcast address -1 Subnet number =2^ subnet number -2 A number of host 2^ host -2 number Subnetting is realized by changing the subnet number. For example, a C class IP address, default subnet mask is 24,111111110000000 is converted into a binary representation, 10 hexadecimal is 255.255.255.0. If this is the subnet mask, 8 behind them can be used as the host location, 8 times 2 is equal to 256, a total of 256 IP position, because of the 2 can not be used, so the available host location 254. But you have to take such an address is divided into 2 sub networks, it is necessary to come up with a bit from the host as the network address, network address is 25. The corresponding flight became 7, 7 times 2 is equal to 128, a total of 126 available. This is from the forward. It is known to the number of sub network division, for each sub network hosts. But in the actual work is often the first to know the number of hosts per subnet, subnet to let you. Is actually very simple. First you count the host number closer to 2 times, then the host number is several. The host is a network of 32 less. For example. If you have a class C IP address 192.168.0.0. If you want to divide 2 subnets, a 100 computer, another 50 computer. 100 more than 6 times 2, 7 times less than 2, so the host digit 7. Then the network digit is 32-7=25. Is a 25 bit subnet mask1111111110000000 is converted to 10 hexadecimal 255. 255. 255.128, this is the first subnet subnet mask, the network number 192.168.0.0/25, network address 192.168.0.0, host 192.168.0.1~192.168.0.126 address, the broadcast address is 192.168.0.127 50 more than 5 times 2, 6 times less than 2, so the host digit 6. Then the network digit is 32-6=26. Is a 26 bit subnet mask1111111111