We can see the rapid growth of internet users in last few years and this increase also create challenges for internet management groups, stake holders and service providers. Day by day infrastructure of internet is expanding and we can even enjoy the service of internet in villages and remote areas. Increased of usage also increase online devices. In start internet protocol addressing (a specific IP addressing for each online entity) was designed on 32 bit and this scheme IP version called IPv4.IPv4 addressing is like 203.128.076.001. decimal is used to make the IPv4 addresses more palatable for humans and a 32-bit address becomes 4 decimal numbers separated by the period (.) character. If we calculate these decimal values and we can get the total number of devices can be participate on this protocol (256x256x256x256) = allows for 4,294,967,296 addresses. It is about 4 billion of addresses and in early days of internet no one can think, 4 billion slot will be full. here we shall discus some disadvantages of IPv4 as we have seen addressing capability problem and after that we shall go through the solution which will replace IPv4 and addressing structure of the new addressing scheme. we shall go through some disadvantages of IPv4 and new features of IPv6.
Rapid Growth of the Internet and the Exhaustion of the IPv4 Addressing
IPv4 allows for 4,294,967,296 addresses which is about 4 billion and IP allocation limits the public IP addresses to a few hundred million. Cause of this limitation companies using NAT (Network Address Translator) to map single public IP to multiple private IP addresses.
IPv4 Security at IP Level
When we communicate at public medium we need to encrypt data to maintain security and privacy. After a passage of time we have now security for IPv4 packets. This security knows as internet protocol security or IPSec but this is an optional for IPv4.
Internet Backbone Maintaining Large Routing Tables
In IPv4 network IDs allocation is very critical and currently more than 87000 routes in the routing tables of internet backbone routers today. The routing infrastructure is based on flat and hierarchical routing.
Quality of Service Concern in IPv4
Now a days internet users are not only limited with browsing and searching data. Current users are well aware of text and voice and video chat and video conferences and online video libraries. This kind of communication need real time data transfer for quality of service. Normally for these kind of services we use UDP (User Data-gram Protocol) or TCP (Transmission Control Protocol).IPv4 TOS field has limited functionality and, over time, has been redefined and locally interpreted. Additionally, payload identification that uses a TCP or UDP port is not possible when the IPv4 packet payload is encrypted.
As we can see we have some basic problems in practice of IPv4 now we will check some new features of IPv6. here I like to describe the some of basic features of IPv6. Deployment of IPv6 is a big challenge for internet management groups, stake holders and service providers. It is difficult but not impossible. We can see benefits of IPv6 here. Biggest upgrade jump from IPv4 32 bit to IPv6 128 bit.
IPv6 Header Format
New header is designed to minimize header overhead. by moving both nonessential and optional fields to extension headers that are placed after the IPv6 header. IPv6 header is more efficiently processed at intermediate routers and that generates efficiency. IPv6 is 4 time larger than IPv4 and its header size is twice than older version.
IPv6 Large Addressing Space
In IPv6 source and destination addresses is based on 128 bit. 128 bit addressing can produce over 3.4 x 1038 possible combinations. Currently we can say this is enough but who know about future may be it also face same problem like IPv4 after some decades. 128 bit addressing allow us multiple levels of sub-netting and address allocation. So we can say that we have plenty of address for use in future.
Addressing and Routing Infrastructure Efficiency in IPv6
IPv6 designed to create an efficient, hierarchical, and summarize able routing infrastructure that is based on the common occurrence of multiple levels of Internet Service Providers. It reduce the size of routing table of backbone routers. Which is can cause of efficient internet experience.
Security features is now built-in
IPv6 has been design to support IPsec (AH and ESP header support required) also support mobility version Mobile IPv6. 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 form developers who built-in security features in development of IPv6 rather we bolt on later.
Quality of Service (QoS) of IPv6
As we have already seen about the UDP and TCP protocols for streaming and other multimedia services on internet. Cause the usage of these services are increasing day by day IPv6 have a flow level field in its header which make better and special handling for packets from source to destination. Data traffic is identified in the IPv6 header, support for QoS can be achieved even when the packet payload is encrypted with IPSec and ESP.