For example, for Class C, it has to be 192-223 (inclusive).
Subnet mask table class a free#
Is this perception correct? So, Class A is always better, even if some IP addresses are wasted in the beginning, it can always grow in future? So, my question is, on which condition or constraint, a particular Class of address will be picked by the network admin? Is he free to choose any class of address?Īlso, I read that, starting octet of a particular class of address needs to fall into a range. This p appears to me like, if a network administrator uses Class C address, then, he will be limited to have maximum of 254 hosts (excluding 0 and 255), whereas, if he chooses Class A address, then, he can have maximum number of hosts to give IP addresses to. I have read about Classes of address like Class A, B, C.Īs I observe the Default Subnet mask for each of these classes, I see that, starting from Class A, gradually, network mast/prefix length increases.Ĭlass B: 255.255.0.0 (prefix length : 16)Ĭlass C: 255.255.255.0 (prefix length : 24) But, just wanted to clear any doubts as a starter for this topic. They append a suffix of the form /n to the host’s IP address to indicate the subnet mask, in which n equals the number of binary 1s in the subnet mask. Some TCP/IP configuration programs, such as those for Ascend routers, use a different notation for specifying subnet masks. The table also shows how these subnet masks would partition an IP address such as w.x.y.z into a network ID and a host ID portion.ĭefault Subnet Masks for IP Addresses Class Default Subnet Mask Network ID Host ID A 255.0.0.0 w x.y.z B 255.255.0.0 w.z y.z C 255.255.255.0 w.x.y z Ascend routers The default subnet masks for IP address classes A, B, and C are shown in the following table.
Taking the logical NOT of the subnet mask and ANDing it with the host’s IP address gives the host’s Host ID: Host = 11001111 00111101 00010000 01110111 Converting these two numbers to binary and ANDing them gives the host’s Network ID: Host = 11001111 00111101 00010000 01110111 When the inverse of the subnet mask (for example, NOT mask) is logically ANDed with the IP address of the host, the result is the host ID of the host – the portion of the host’s IP address that uniquely identifies the host on its network.įor example, consider the IP address 207.61.16.119 and the subnet mask 255.255.255.0. When the subnet mask is logically ANDed with a 32-bit IP address of a TCP/IP host, the result is the network ID of the host – the portion of the host’s IP address that identifies which network the host is on. In binary notation, decimal 0 represents the octet 00000000, and decimal 255 represents 11111111.Ī subnet mask consists of 32 binary digits, the first n of which are 1s and the remaining of which are 0s. Subnet masks are represented as four-octet dotted-decimal numbers, just as IP addresses are, except that the most common values for an octet in a subnet mask are 0 and 255.
0 kommentar(er)
