IPv4 and IPv6
In recent years, the rapid growth of Internet users, Internet management groups, stakeholders and service providers are also facing challenges. Internet day-to-day infrastructure is expanding, even in rural and remote areas to enjoy Internet services. Increased use also increased the online equipment. At startup, Internet Protocol addressing (specific IP addressing for each online entity) is designed in 32 bits, and the IP version of the scheme is called IPv4.IPv4 addressing is similar to 203.128.076.001. Decimal is used to make IPv4 addresses more suitable for humans, 32-bit addresses into four decimal digits, separated by a period (.). If we calculate these decimal values, we can get the total number of devices that the protocol can participate in (256x256x256x256) = allow 4,294,967,296 addresses. About 4 billion of the address of the Internet early no one can think of, 4 billion of time will be filled. Here, we will discuss some of the shortcomings of IPv4, because we have seen the ability to solve the problem, then we will be through the solution to replace the IPv4 and addressing the structure of the new addressing scheme. We will understand some of the shortcomings of IPv6 and the new features of IPv6
The rapid growth of Internet and the depletion of IPv4 addressing
IPv4 allows 4,294,967,296 addresses, about 4 billion , IP allocation will be limited to hundreds of millions of public IP address.
 IPv4 Security of IP Layers
When we communicate, the company uses NAT (Network Address Translator) to map public IP to multiple private IP addresses. Need to encrypt data to maintain security and privacy. After a while, we now have the security of IPv4 packets.
In the IPv4 network ID allocation is very critical, the current Internet backbone router routing table currently has more than 87,000 routes.
Now that Internet users are not limited to browsing and searching for data. Current users are well aware of text, voice and video chat, video conferencing and online video library. This communication requires real-time data transmission to provide quality of service. For these types of services, we use UDP (User Data-Protocol) or TCP (Transmission Control Protocol). The IPv4 TOS field has limited functionality and has been redefined and interpreted locally over time. In addition, when the IPv4 packet payload is encrypted, it is impossible to use the payload identification of the TCP or UDP port
We can see that we have some Basic Issues In IPv4 practice, we will examine some of the new features of IPv6. Here I would like to introduce some of the basic characteristics of IPv6. The deployment of IPv6 is a big challenge for Internet management groups, stakeholders and service providers. It is difficult but not impossible. We can see the benefits of IPv6 here. IPv6 header format
The new title is designed to minimize overhead overhead. By moving the nonessential and optional fields to the extension header placed after the IPv6 header. IPv6 headers are more efficient and efficient in intermediate routers. IPv6 is larger than IPv4 and its header size is twice the size of the old version
IPv6 large addressing space
IPv6 source and destination addresses are based on 128 bits. 128-bit addressing can produce more than 3.4 × 1038 possible combinations. At present we can say that this is enough, but who knows the future may also face the same problem, such as IPv4 after decades. 128-bit addressing allows us to allocate multiple levels of subnets and addresses.
  IPv6 addressing and routing infrastructure efficiency
IPv6 is designed to create an efficient, hierarchical, summary based on multiple levels of Internet service provider common The ability to route the infrastructure. Reduce the size of the backbone router routing table.
  The security function is now built
IPv6 has been designed to support IPsec (requires AH and ESP header support) to support Mobile Mobile IPv6. IPSec negotiates security settings based on two types of extension headers and protocols. The authentication header (AH) provides data integrity, data authentication, and replay protection for the entire IPv6 message.
As we have said, IPv6 developers have built-in security features, have seen on the Internet for the Streaming media and other multimedia services UDP and TCP protocols. Because of the increasing use of these services, IPv6 has a process-level field in its head that can better handle packets from the source to the destination. Identify data traffic in IPv6 headers, even when IPSec and ESP are used to encrypt packet payloads