With the rapid development of the Internet and the rapid progress of network technology, IPv4 protocol as the core technology of the Internet has achieved great success. However, after decades of development, some inherent limitations and resource depletion of IPv4 protocol gradually emerged, unable to meet the needs of network development. In order to solve the shortcomings of IPv4 and meet the needs of the future Internet, IPv6 protocol came into being, its importance is to solve the following shortcomings of IPv4:
1. Limitations of the IP address space: Limitations of the IP address space have always been an important challenge faced by the IPv4 protocol. Because IPv4 uses 32-bit address bits, there are theoretically only 2^32 (about 4.3 billion) available IP addresses. In the early days of the Internet, such address space seemed to be enough to meet the demand, but with the rapid development and popularity of the Internet, IPv4 address resources have gradually come to an emergency and are close to exhaustion.
There are two main reasons for the exhaustion of IPv4 addresses: First, the explosive growth of the number of Internet users, especially the popularity of mobile Internet, each device needs a unique IP address, which leads to a rapid increase in IP address consumption; Second, the distribution of IPv4 addresses is not uniform, some regions or organizations have obtained a large number of IP addresses, while other regions are relatively scarce, which leads to an uneven distribution of IP address resources.
In order to solve the shortage of IPv4 address resources, IPv6 protocol came into being. IPv6 uses 128-bit address bits, providing 2^128 (about 3.4 x 10^38) available IP addresses, which is almost infinitely more than the number of IPv4 addresses. This allows the IPv6 protocol to provide sufficient address space for the future expansion of the Internet to meet the needs of all devices and users on the planet.
IPv6's address space is so large because it uses 128-bit binary numbers to represent IP addresses, compared to IPv4's 32-bit address, IPv6's address length is longer, and each address bit can take more values, thus achieving a huge increase in the number of available addresses. Even considering the possible technological development and explosive growth of devices in the future human society, the IPv6 address space is still enough to meet the demand, and there will be no IPv4 address exhaustion.
2, the routing table maintained by the backbone router: The routing table maintained by the backbone router is a key component of the Internet, which is responsible for forwarding packets from the source address to the destination address on the best path. However, the discontinuity of IPv4 address assignment has led to the continuous growth of IPv4 BGP (Border Gateway Protocol) routing tables around the world, posing a huge challenge to the management and maintenance of network equipment.
In IPv4, address allocation is not uniform, because the importance of continuous allocation of address blocks was not considered in the early planning of the Internet. As a result, many IPv4 address blocks are distributed very loosely and cannot effectively aggregate routes. As packets travel across the Internet, routers need to look up the routing table to find the best forward path. However, due to the distributed nature of IPv4 addresses, a large amount of address information needs to be recorded in the routing table, resulting in a large routing table.
The number of entries in the global IPv4 BGP routing table continues to grow, even with CIDR (Classless Interdomain Routing) aggregation method, there are currently about 700,000 routing entries. This huge routing table not only consumes a lot of memory resources, but also affects the efficiency of router forwarding. The larger the routing table, the longer the route search time, which affects the packet forwarding speed and the response time of the network.
IPv6 uses more regular address allocation and route aggregation, which makes routing table management more efficient and simplified. The IPv6 address consists of 128 bits, which can represent a large number of addresses, and the allocation is more continuous, avoiding the problem of scattered addresses in IPv4. In IPv6 networks, the number of routing tables maintained by backbone routers is relatively small, because the regularity of IP addresses makes route aggregation easier to implement.
IPv6 address regularity and route aggregation facilitate the management and maintenance of network devices. A small number of routing tables reduces the burden on routers and improves the efficiency of route lookup, thus improving the performance and response speed of the network. In addition, IPv6 also introduces more optimization mechanisms, such as fast routing and traffic engineering, to further improve the efficiency and stability of the network.
3, the host terminal configuration is complicated: IPv4 network, the user needs professional guidance and setting when the host to connect to the network, the process is complicated. IPv6 introduces automatic configuration technology to achieve "plug and play", making it easier for users to access the network.
Inadequate security support: The IPv4 protocol did not initially consider network security and lacked support for security. IPv6 takes IPSec as its actual component to provide more comprehensive network security.
4. Insufficient QoS support: IPv4 network does not provide quality of service assurance, and cannot meet the QoS requirements of services. IPv6 introduces a Traffic Class field and a Flow Label field to enable better quality of service management.
Therefore, as an upgraded version of IPv4, IPv6 protocol not only solves many shortcomings of IPv4, but also provides more robust and comprehensive technical support for the future development of the Internet. With the exhaustion of IPv4 address resources approaching, the promotion and adoption of IPv6 protocol has become an important task worldwide to ensure the continued development and robust operation of the Internet. The popularization of IPv6 will bring us a wider cyberspace and a more secure and efficient Internet experience.