With the rapid development of the Internet, the demand for IP addresses is increasing, and traditional category-based IP address allocation methods can no longer meet the demand. This allocation results in a lot of address waste, and as the number of users increases, the IPv4 address space is gradually depleted. In addition, the traditional method also leads to bloat of the routing table, which affects the performance of the router and the stability of the Internet.
To solve these problems, CIDR (Classless Inter-Domain Routing) was born. It is designed to make more efficient use of IP address space, reduce the size of routing tables, and improve the performance and stability of the Internet.
The core idea of CIDR is to introduce the concept of prefix length, which allows network administrators to be more flexible in dividing IP addresses by specifying the number of bits of a network prefix. This flexibility allows us to assign IP addresses more precisely, avoiding address waste in traditional methods.
Compared to traditional IP address assignments, CIDR offers the following advantages:
1. Efficient use of address space.
In the traditional way of IP address allocation, each category has a fixed number of host addresses and network addresses. This results in a lot of address waste. The flexibility of CIDR allows us to make more precise address assignments based on actual needs, avoiding waste. This flexibility allows network administrators to make more efficient use of IP address space by dividing address blocks more granularly according to actual needs. In CIDR, network administrators have the flexibility to divide IP addresses based on the size and structure of the organization, avoiding address waste in traditional classification methods. This more precise way of assigning addresses makes the use of IP addresses more efficient and meets the needs of the growing number of Internet users.
2. Reduce the size of the routing table.
The traditional way of assigning IP addresses can cause the routing table to bloat rapidly, affecting the performance of the router and the stability of the Internet. The CIDR concept of prefix length allows us to aggregate adjacent address blocks, reducing the number of entries in the routing table and making routing more efficient. With the prefix length concept of CIDR, routers can process entries in the routing table more efficiently. Since CIDR allows the aggregation of adjacent address blocks, the number of entries in a routing table is greatly reduced. This improves the processing performance of the router and reduces the size of the routing table, which improves the stability and reliability of the Internet.
3. Improve the flexibility of network design.
In the traditional IP address allocation method, the network design is limited by categories and is less flexible. The flexibility of CIDR allows us to design the network according to actual needs, better adapt to changes in the internal structure of the organization, and make it easier to respond to the different needs of different departments or business units for network resources. In CIDR, network administrators have the flexibility to design a network structure based on the actual needs of the organization. No longer limited by traditional classification methods, network administrators can divide and manage more granularly according to the needs of departments or business units. This flexibility allows organizations to better adapt to changes in internal structures while meeting the demands of different departments or business units for network resources.
In summary, CIDR (Classless Inter-Domain Routing) makes the assignment of IP addresses more flexible and precise by introducing the concept of prefix length. It solves the problem of IPv4 address space depletion and routing table bloat, improving the performance and stability of the Internet. The widespread use of CIDR will usher in a new chapter in Internet address allocation and lay a solid foundation for the future development of the Internet.