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 villages and remote areas. Increased usage also increases online devices. Initially, Internet Protocol addressing (a specific IP addressing for each online entity) was designed in 32-bit, and this IP version of the scheme was called IPv4. Decimal is used to make IPv4 addresses more acceptable to humans, 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 get the total number of devices that can participate in this protocol (256x256x256x256) = allows 4,294,967,296 addresses. It’s about 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 disadvantages of IPv4, since we have seen the problem of addressability, and then we will discuss the solution that will replace IPv4 and the addressing structure of the new addressing scheme. we will see some disadvantages of IPv4 and the new features of IPv6.
Rapid growth of the Internet and the depletion of IPv4 addressing
IPv4 allows 4,294,967,296 addresses, which is about 4 billion, and IP allocation limits public IP addresses to a few hundred million. The cause of this limitation is that companies 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 security for IPv4 packets. This security is known as Internet Protocol Security, or IPSec, but is optional for IPv4.
Internet backbone that maintains large routing tables
In IPv4, network ID assignment is very critical and there are currently over 87,000 routes in the routing tables of Internet backbone routers. The routing infrastructure is based on flat and hierarchical routing.
Quality of service problem 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 chats, video conferencing, and online video libraries. This type of communication needs real-time data transfer for quality of service. Normally for this type of services we use UDP (User Data Protocol) or TCP (Transmission Control Protocol). The IPv4 TOS field has limited functionality and has been locally redefined and interpreted over time. Also, identifying the payload that is using a TCP or UDP port is not possible when the IPv4 packet payload 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. IPv6 implementation is a major challenge for Internet governance groups, stakeholders, and service providers. it’s difficult but not impossible. We can see the benefits of IPv6 here. Major upgrade leap from 32-bit IPv4 to 128-bit IPv6.
IPv6 header format
The new header is designed to minimize header overhead. by moving the non-essential and optional 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 address 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 who knows about the future, you may also face the same problem as IPv4 after a few decades. 128-bit addressing allows us multiple levels of subnetting and address assignment. So we can say that we have many directions to use in the future.
Addressing and routing infrastructure efficiency in IPv6
IPv6 designed to create an efficient, hierarchical, and resumable routing infrastructure that is based on the common occurrence of multiple levels of Internet Service Providers. Reduces the size of the routing table of trunk routers. Which can cause an efficient Internet experience.
Security features are now integrated
IPv6 has been designed to support IPsec (AH and ESP header support required) and also supports the mobile version of Mobile IPv6. IPSec based on two types of extension headers and a protocol for negotiating security settings. The Authentication Header (AH) provides data integrity, data authentication, and replay protection for the entire IPv6 packet. It is better to train the developers who incorporated security features in the development of IPv6 rather than have us do it 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. Because the use of these services is increasing day by day, IPv6 has a flow level field in its header that does better and special handling of packets from source 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.
