We can see the rapid growth of Internet users in recent years and this increase also creates challenges for Internet management groups, stakeholders, and service providers. Day by day the Internet infrastructure is expanding and we can even enjoy Internet service in remote towns and areas. Increased usage also increases online devices. In principle, the Internet Protocol addressing (a specific IP addressing for each online entity) was designed in 32 bits and this version of IP scheme called IPv4.IPv4 is like 203.128.076.001. The decimal is used to make IPv4 addresses more human-friendly and a 32-bit address is converted to 4 decimal numbers separated by the period character (.). If we calculate these decimal values and we can obtain the total number of devices that can participate in this protocol (256x256x256x256) = allows 4,294,967,296 addresses. There are roughly 4 billion addresses and in the early days of the Internet no one can think, 4 billion slots will be full. Here we will discuss some of the disadvantages of IPv4 as we have seen the addressing capacity problem and then we will discuss the solution that will replace IPv4 and the addressing structure of the new addressing scheme. We will go over some of the downsides of IPv4 and the new features of IPv6.
The rapid growth of the Internet and the depletion of IPv4 addressing
IPv4 allows 4,294,967,296 addresses which is approximately 4 billion and the IP allocation limits public IP addresses to a few hundred million. Cause of this limitation companies that use NAT (Network Address Translator) to map a single public IP to multiple private IP addresses.
IPv4 security at the IP level
When we communicate in a public medium, we need to encrypt the data to maintain security and privacy. After a while, we now have IPv4 packet security. This security is known as Internet Protocol security or IPSec, but it is optional for IPv4.
Internet backbone that maintains large routing tables
In IPv4, network ID assignment is very critical and there are currently more than 87,000 routes in the routing tables of Internet backbones. The routing infrastructure is based on flat and hierarchical routing.
Concern about the quality of service in IPv4
Today, Internet users are not only limited with browsing and searching for data. Today’s users are well aware of text, voice, and video chat, video conferencing, and online video libraries. This type of communication requires data transfer in real time for quality of service. Normally for this type of services we use UDP (User Data -gram Protocol) or TCP (Transmission Control Protocol). The IPv4 TOS field has limited functionality and has been redefined and interpreted locally over time. Also, identification of the payload using a TCP or UDP port is not possible when the payload of the IPv4 packet is encrypted.
IPv6
As we can see we have some basic problems in IPv4 practice, now we will review some new features of IPv6. here I like to describe some of the basic features of IPv6. Implementing IPv6 is a huge challenge for Internet management groups, stakeholders, and service providers. it’s difficult but not impossible. We can see the benefits of IPv6 here. Biggest upgrade jump from 32-bit IPv4 to 128-bit IPv6.
IPv6 header format
The new header is designed to minimize header overhead. by moving the optional and nonessential fields to the extension headers that are placed after the IPv6 header. The IPv6 header is processed more efficiently on intermediate routers and that creates efficiency. IPv6 is 4 times larger than IPv4 and its header size is double that of the previous version.
Large IPv6 addressing space
In IPv6, the source and destination addresses are based on 128 bits. 128-bit addressing can produce more than 3.4 x 1038 possible combinations. Currently we can say that this is enough, but whoever knows about the future may also face the same problem as IPv4 after a few decades. 128-bit addressing allows us multiple levels of subnets and address assignment. So, we can say that we have many directions to use in the future.
Efficiency of the addressing and routing infrastructure in IPv6
IPv6 designed to create an efficient, hierarchical and summary routing infrastructure that is based on the common occurrence of multiple levels of Internet service providers. Reduces the size of the routing table of the trunk routers. What can cause an efficient Internet experience.
Security features are now integrated
IPv6 is designed to support IPsec (AH and ESP header support required) and also supports the mobile IPv6 mobility version. IPSec based on two types of extension headers and a protocol to negotiate security settings. The Authentication Header (AH) provides data integrity, data authentication, and replay protection for the entire IPv6 packet. It is better for developers to incorporate security features into IPv6 development rather than later.
IPv6 Quality of Service (QoS)
As we have already seen about the UDP and TCP protocols for streaming and other multimedia services on the Internet. As the use of these services increases day by day, IPv6 has a flow level field in its header that makes a better and special handling of packets from origin to destination. Data traffic is identified in the IPv6 header, QoS support can be achieved even when the packet payload is encrypted with IPSec and ESP.