IPv4, also known as Internet Communication Protocol Version 4, was the first widely deployed and used version of the Internet. However, with the rapid development of the Internet and the increasing number of network devices, IPv4 protocol has gradually exposed a series of problems, the most important problem is insufficient address space. The IPv4 address space is only about 4 billion, which is very limited given the size of the Internet today. In response to the growing demand for network connectivity and the expansion of the Internet, IPv6 protocol was proposed and gradually replaced IPv4, which introduced a larger address space, better routing efficiency and other advantages, making the upgrade to IPv6 an inevitable trend.
The reasons for upgrading IPv4 include the following:
1. Insufficient address space: The approximately 4 billion addresses provided by IPv4 are already far from enough to meet the growing number of Internet devices worldwide. With the rapid adoption of mobile devices, the Internet of Things, and massively connected smart devices, IPv4 address exhaustion has become more urgent and serious.
IPv4 uses a 32-bit address length, which results in a theoretical maximum of 2^32 (approximately 4.295 billion) different IP addresses. However, due to historical reasons and improper address allocation, some IP addresses are reserved for specific purposes, such as private addresses (such as 192.168.0.0/16 and 10.0.0.0/8), loopback addresses (127.0.0.0/8), and broadcast addresses, which further shrinks the available public IP address space.
Problems caused by NAT technology: NAT, or network address translation, is a network translation technology introduced to solve the problem of insufficient IPv4 address space. It allows multiple devices to share a public IP address by mapping private IP addresses to public IP addresses. While NAT alleviates the shortage of IPv4 addresses to some extent, it also brings a series of complex management and security issues, as well as some limitations that hinder global interconnection and direct communication. In IPv4, the number of ports is limited, only 65535 ports are available, some of which are reserved for specific purposes, such as port 80 for HTTP protocol, port 443 for HTTPS protocol and so on. As a result, under the IPv4 protocol, the number of ports available per device is limited, and some emerging applications, especially streaming media and video conferencing tools, put forward higher requirements for greater bandwidth and latency-free network support, requiring more ports to ensure efficient transmission and real-time data.
4, low routing efficiency: Under the IPv4 protocol, routing efficiency is limited. When the Internet traffic continues to increase, the burden of routers also increases, resulting in network congestion and delay.
In IPv4, routing tables are an important part of determining the best path for packets. Due to the limited IPv4 address space, the size of the routing table in the Internet is becoming larger and larger, and such a large-scale routing table requires more memory and processing power to maintain and query, resulting in an increasing burden on the router. Especially on a global scale, when hundreds of millions of devices are connected to the Internet and generate massive amounts of data, the size of the IPv4 routing table will become unusually large, placing extremely high demands on the performance and processing power of routers.
This expansion of routing tables also leads to problems of network congestion and latency. When the load on the router reaches its limit, packets can experience congestion and delays in transit, resulting in reduced network performance. Especially during peak hours or under heavy load conditions, network latency can increase significantly, affecting users' requirements for real-time performance and interactivity.
IPv6 protocol uses a more efficient routing mechanism, its address space is huge, using 128-bit address length, can provide about 3.4x10^38 addresses, such a large-scale address space makes IPv6 routing table size is relatively small, route search more quickly and efficiently. Therefore, the IPv6 protocol can better cope with the challenges of increasing Internet traffic, improve the routing efficiency of the network, and reduce network congestion and latency problems.
As an upgraded version of IPv4, IPv6 brings many advantages and solves the problems faced by IPv4. First, the IPv6 address space is quite large, about four times the size of the IPv4 address space, providing about 340 trillion trillion trillion addresses, more than enough to cope with the needs of Internet devices for decades to come. Secondly, IPv6 uses more efficient routing technology to reduce network congestion and improve network transmission efficiency. In addition, IPv6 also provides better security and privacy protection mechanisms to provide users and devices with a more secure Internet experience.
In general, IPv4 protocol is upgraded to IPv6 protocol because IPv4 address space is insufficient, routing efficiency and other problems are gradually emerging, and IPv6 as its upgraded version, to solve these problems and bring a larger address space and more efficient network transmission, for the future development of the Internet to provide a more robust and sustainable foundation. Therefore, the wide application of IPv6 and the gradual replacement of IPv4 has become the trend of global network development.