Overview of Subnet Class

A subnet class is a term used to refer to a range of IP addresses with a specific network prefix length. IP addresses are divided into the following classes: Class A, Class B, Class C. Class D, and Class E. Each class has a fixed number of network and host bits. Each of these classes has a fixed network portion and a fixed host portion, and the size of the network and the number of hosts that could be connected to it are predetermined based on the class.

Class A

Class A subnet is a range of IP addresses that falls within the Class A IP address space. Class A IP addresses are those that have the first octet (or the first 8 bits) reserved for the network portion of the address. The remaining 24 bits are used to identify the host within the network. Class A IP addresses can support a large number of hosts and are typically used by organizations that have very large network infrastructures.

  • Public IP Range: 1– 126 
  • Subnet Mask: 255.0.0.0
  • Number of Hosts: 126                                                                               
  • Number of Networks: 16,777,214                             

Class B

Class B subnet refers to a specific range of IP addresses allocated to a particular organization or network. This means that Class B subnets have 16 bits for the network portion and 16 bits for the host portion. Class B addresses are used for medium to large-size networks.

  • Public IP Range: 128-191                                                                                    
  • Subnet Mask: 255.255.0.0                                                                                  
  • Number of Hosts:  16,382                                                                                
  • Number of Networks: 65,534

Class C

Class C addresses are used in small Local Area networks (LAN). Class C subnets are often used for small office or home networks, as well as for devices such as printers, cameras, and other networked devices that do not require a large number of IP addresses. Class C subnets have 24 bits for the network portion and 8 bits for the host portion.

  • Public IP Range: 192-223                                                                                           
  • Subnet Mask: 255.255.255.0                                                                             
  • Number of Hosts: 2,97,150                                                                                         
  • Number of Networks: 254

Class D

Class D addresses are used for multicasting, which is the transmission of data from one sender to multiple recipients. These addresses are identified by the first four bits of the first octet, which are always set to 1110, and the remaining 28 bits are used to identify the multicast group. Multicasting allows for more efficient use of network resources as data can be sent to multiple recipients simultaneously. Class D addresses are used in various applications, including video and audio streaming, online gaming, and real-time data distribution. Public IP ranges from 224 to 239.

Class E

Class E addresses are reserved for experimental purposes and are not intended for use in general networking. Unlike the other classes of IP addresses, Class E addresses are not used for actual network addresses. Instead, they are used for research and development purposes and are not available for public use. Instead, most networking applications use Class A, B, and C addresses for their network addressing needs. Public IP ranges from 240 to 255.

Special IP Address

The IP range from 127.0.0.0 to 127.255.255.255 is reserved for either a loopback or a local host address. This loopback IP address is managed within the operating system. These range IPs are network testing addresses and they cannot assign to a device.