IPv4 is the fourth Internet Protocol (IP) version. It is a unique set of numbers used to identify devices connected to the Internet.
An IPv4 address consists of a string of 32 bits, usually written in a format like “0.0.0.0.” Each address is crucial to its connecting devices. It is used by devices to communicate with each other within a network and with the broader internet.
IPv4 addresses have five classes developed to assign the nearly 4.3 billion IP addresses worldwide. Continue reading to learn more about the IP classes and their ranges.
🔑Key Takeaways:
- There are classes of IPv4 addresses: Class A, B, C, D, E. Each one is designed with a specific IP address that determines the capacity of devices on a network.
- Class A is designed for large networks (i.e., organizations). It ranges from 0 to 127.
- Class B is best for medium-sized networks (i.e., multinational companies). It ranges from 128 to 191.
- Class C is used for smaller networks (i.e., schools and colleges). It ranges from 192 to 223.
- Class D is suitable for multicasting, which simultaneously allows a single host to transmit data to numerous recipients over the Internet. However, it is not used for assigning IP addresses to devices. It ranges from 224 to 239.
- Class E is reserved for future, experimental, and developmental purposes. It is not given to hosts or for general use. It ranges from 240 to 255.
- IPv4 addresses send data in 3 ways: unicast, broadcast, and multicast.
5 Classes Of IPv4 Addresses
An IPv4 address is divided into four octets, which are bytes that range from 0 to 255. These octets are then converted to binary to represent the actual IP address.
The IP address format is typically split into these two sections:
- Network: This section uniquely identifies the network of the host or device.
- Host: This identifies the device within a specific network.
Specific networks within the address space are reserved for private use. These networks employ internal IP addresses not routed across the public Internet. This segregation allows private networks to utilize IPv4 addresses without interfering with other networks.
There are five IPv4 classes: Class A, B, C, D, and E. Each one encompasses a specific IP address range that determines the capacity of devices on a network.
The sections below will provide an in-depth discussion of each IPv4 class.
1. Class A
The Class A IP address is designed for large networks, like large organizations. This class allocates 8 bits for the network portion and 24 bits for the host. The first bit is always set to 0.
IP addresses in Class A have a range from 0 to 127. The public IP range is from 0.0.0.0 to 127.0.0.0. The private IP range lies from 10.0.0.0 to 10.255.255.255.
An example of an IP address in IPv4 Class A is 127.52.101.9.
The number of networks in this class is 128, with 16,777,216 addresses per network. It accommodates a total of 2,147,483,648 unique addresses.
| 💡 Did You Know: The first versions of IP address, IPv4, were launched in 1981. Currently, there are 4 main types of IP addresses: private, public, static, and dynamic. |
2. Class B
Medium-sized networks, like multinational companies, use Class B IP addresses. In this class, the network and host portions consist of 16 bits. In binary form, the first bits are 10.
Class B addresses’ range is from 128 to 191. The range of public IP addresses within this class goes from 128.0.0.0 to 191.255.0.0. On the other hand, the private IP range is from 172.16.0.0 to 172.31.255.255.
A sample of an IPv4 Class B address would be 146.73.10.241.
Class B provides 16,384 networks, each capable of accommodating 65,536 addresses. This means the overall number of available IPv4 Class B addresses is 1,073,741,824.
| IP address classes explained | class A , B ,C ,D ,E | Free CCNA 200-301 |
3. Class C
The Class C IP address is typically used for smaller networks like colleges. This class allocates 21 bits for the network portion and 8 for the host. The first bits assigned are 110.
The address range of Class C falls between 192 and 223. For public IP addresses, the range spans from 192.0.0.0 to 223.255.255.255. The private IP range lies from 192.168.0.0 to 192.168.255.255.
This is an example of an IPv4 Class C address: 198.215.7.21.
Class C offers a total of 2,097,152 networks, each accommodating 256 addresses. Consequently, there are a total of 536,870,912 addresses available under this class.
| 🎉Fun Fact: Your IP address is your virtual home address for your device, expressed in numbers understood by computers. The IP address plays a vital role in data transfer, helps you identify your device, monitors your geographical location, and allows administrators to track your data. |
4. Class D
Class D allows multicasting. It permits a single host to simultaneously transmit data to numerous recipients over the Internet.
However, this class of IPv4 is not utilized for assigning IP addresses to devices.
The first bits of Class D IPs are 1110, lacking any segregation between host and network addresses. Its range extends from 224 to 239. The starting address for this class is 224.0.0.0, ending in 239.255.255.255.
An example of an IP address belonging to IPv4 Class D would be 229.163.4.51.
The exact count of networks and addresses per network remains undefined. However, it is estimated that there are 268 million addresses in this class.
5. Class E
Class E addresses are reserved for future use, experimental, or research and development purposes. They are not given to hosts or for general use.
The first bits of Class E addresses are designated as 1111. Its range spans from 240 to 255, starting with the address 240.0.0.0 and ending with 255.255.255.255.
A sample IP address from IPv4 Class E is 251.39.164.227.
Like Class D, this class does not define specific networks or addresses per network. The estimated total number of addresses for Class E is 268 million.
How Do IPv4 Addresses Work?
IPv4 is a significant part of the IP system that helps devices communicate online. It uses a unique addressing system to identify and send data between computers.
This version has three ways of sending data:
- Unicast
Data is sent to just one host. The destination address field has the computer’s address it’s going to.
A computer transfers data to a specific server. It’s similar to sending an email to one person.
- Broadcast
Data is sent to all hosts on a network. The destination address field has a particular broadcast address.
Every computer on the network will get the data, and any host that receives the packet will handle it. It’s similar to sending a message to everyone on a mailing list.
- Multicast
Data is sent to a group of hosts. The destination address includes a unique address.
More than one computer can receive it. It’s like reaching a specific group, similar to targeting a marketing campaign to people in a particular country.
The broadcast mode is similar to the process of sending messages to everyone. Meanwhile, the multicast method is more focused and reaches specific audiences.
Conclusion
The prevalent Internet usage revolves around the five classes of IPv4 addresses. These IP classes cater to the majority of devices.
Understanding each of the IPv4 classes is crucial for learning the structure and functionality of IP addresses.
FAQs
How many blocks does an IPv4 Class A have?
An IPv4 Class A has 128 blocks, numbered from 0 to 127. Each block represents a range of addresses.
How many private IPv4 addresses are there?
There are around 22 million unique private IPv4 addresses that an organization can use internally.
Sources
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Muninder Adavelli is a core team member and Digital Growth Strategist at Techjury. With a strong background in marketing and a deep understanding of technology's role in digital marketing, he brings immense value to the TechJury team.