Subnet and supernetwork Analysis

Subnet and supernetwork Analysis★Subnet subnet mask is a technology used in combination with IP addresses. It must be used together with the IP address. The subnet mask has only one function, namely dividing an IP address into a network address and a host address. You can divide the host number of an IP address into two parts to identify the subnet. The IP address can be expressed as the network number, subnet number, and host number. The subnet mask of www.2cto.com is a 32-bit binary number. It tells the host that the IP addresses correspond to network numbers, subnet numbers, and host numbers. in the subnet mask, part of the network ID is 1, and part of the host ID is 0. Therefore, when the IP address and subnet mask are "and", the non-zero part is the network number, and the zero part is the master machine number. For example, if the IP address is 172.16.80.28 and the subnet mask is 255.255.192.0, The subnet address is 172.16.64.0. based on actual needs, you can use the subnet mask of Class B or Class C addresses (255.255.0.0 or 255.255.255.0 ), change the network number of the original Class A address from one byte to two or three bytes, or use the subnet mask (255.255.255.0) of the class C address ), change the network number of the original Class B address from two bytes to three bytes, thus increasing the number of networks and reducing the host capacity in each network; you can also use the subnet mask of Class B addresses (namely, 255.255.0.0) to change the subnet mask of class C addresses from three bytes to two bytes, thus increasing the host capacity in each network, reduce the number of networks. A variable-length subnet mask can be defined as a network number in the subnet mask as 1. In this way, you can change the maximum part of the mask whose original value is 0 to 1 by extending the subnet mask, in this way, the part that should belong to the host number is changed to the network number to divide the subnet. It can be seen that the more digits the subnet mask has, the more subnets are obtained, but the less hosts each subnet contains, and the more IP resources are lost. This is because each subnet retains all 0 addresses as network numbers and all 1 addresses as broadcast addresses. Www.2cto.com★The supernetwork and subnet technologies are the opposite. When constructing a supernetwork, some bits from the network number are spliced together with the host number to form a new host number. In the supernetmask, all bits corresponding to the supernetmask are set to 1, and the corresponding host number is set to 0. In the supernetmask, 1 is reduced to achieve network interconnection in different physical networks. When constructing a supernetwork, pay attention to the following points: 1. The address block must be continuous. 2. The number of address blocks to be merged must be 2 to the power of m. M = 3rd, 3... 3. The value of bytes in the first address block of the merged Class C network must be an integer multiple of the address block to be merged. Example: 192.168.168.0 192.168.169.0 192.168.170.0 192.168.171.0192.168.172.0 192.168.173.0192.168.174.0 192.168.175.0
You can combine these eight class C address blocks (Network numbers) into a supernetwork. 3 digits are taken from the starting position of the network number to merge the eight class C address blocks, that is, the mask is 255.255.248.0 (the default mask of the cnetwork is 255.255.255.255.0), and the IP address and mask and operation are performed, the result is 192.168.168.0, which means all hosts in these address blocks think they are located in the same network 192.168.168.0.