China is going to implement IPv6! On November 26, 2017, the General Office of the Central Committee of the Communist Party of China and the General Office of the State Council issued the "Action Plan for Promoting the Large-scale Deployment of Internet Protocol Version 6 (IPv6)", which pointed out that the number of active users of IPv6 in China by the end of 2018 It will reach 200 million, 500 million by the end of 2020, and China's IPv6 scale will reach the world's largest by the end of 2025!

　　 What is IPv6? In short, IPv6 is the sixth version of the IP address protocol. Our network is composed of a large number of IP addresses. In the early years, the IPv4 addresses of the whole world have been allocated, and the spotlight of the historical stage is all on IPv6 facing the far future.

　　 Compared with IPv4, the biggest advantage of IPv6 should be that it can provide nearly unlimited IP addresses. Compared with IPv4, which has only 4.2 billion IP addresses, the address length of IPv6 design is 128 bits. In theory, IPv6 can provide 2 to the 128th power. With the unprecedented development of the mobile Internet and the Internet of Things, IPv4 resources have become less and less in recent years.

After the implementation of IPv6, operators no longer need to assign IP addresses to users through NAT-NAT also requires cost, and some can directly assign IP addresses. The IPv6 promotion plan also clearly states that no new network addresses will be added by the end of 2020. Using private IPv4 addresses, operators naturally have no reason to assign intranet IPs to users.

　　 IPv4 cannot provide sufficient IP addresses, which makes operators have to provide intranet addresses through NAT. However, if you want a public IP, you can apply, but the public IP used by individual users is often not fixed. Which IP is assigned to you depends on the actual situation. IPv4 does not have so many public IPs. One-to-one distribution to users. In any case, in the IPv4 system, it is difficult to one-to-one correspondence between IP addresses and individual users; but in the IPv6 system, this will obviously not be a problem.

　　 In addition to a large number of IP addresses, another advantage of IPv6 that people often talk about is the greatly improved security. In the deployment of IPv6, IPSec was once the standard configuration, which means that data transmission between IPv6 addresses is often encrypted, and information will no longer be easily eavesdropped and hijacked. In IPv6, IPSec has become an unprecedented important agenda. Thanks to the massive public network IP and IPSec, the Internet should become more secure and smooth. So can IPv6 solve the security problems related to plaintext transmission in IPv4? The answer is no, but IPv6 is always more efficient than IPv4, the header is more streamlined, and the forwarding efficiency is higher. In RFC6434, IPSec encryption is no longer a mandatory standard for IPv6. Without IPSec IPv6, the security improvement is limited compared to IPv4. Perhaps because of this, the deployment pressure of IPv6 has been reduced a lot, and network supervision will not get out of control after the deployment of IPv6.