Abstract--- This document provides an analysis and comparison of IPv4 and IPv6 under various circumstances. It is well understood that IPv6 has been designed to replace IPv4. We have done a feature-by-feature comparison and contrast of IPv6 versus
IPv4 and found that IPv6 offers many unique opportunities for increasing a network architectures efficiency and agility. In some sense, there is a competition going on between these protocols, as they are not directly compatible, and network providers and users are being forced to determine whether to support one or both protocols for various network services. The new version of IP,(i.e.
IPv6), constitutes an effort to overcome the inborn limitations of
IPv4, in order for the new protocol be able to respond to the new needs as they shape today in the Internet. This paper is aimed to discuss about various comparison issues when porting an IPv4 application to IPv6 with focus on issues that an application developer would face rather than a complete API reference.IPv4 is the incumbent and currently has the most widespread usage for conventional Internet applications.IPv6 is a large-scale re-design and re-engineering of IPv4, based on many lessons learned as the
IPv4-based Internet grew and was used in unforeseen ways.
Keywords-- IPv4, IPv6, Multicast, Quality of service (QOS),
Routing.
I. INTRODUCTION
HE primary motivation for change arises from the limited address space. When IPV6 deployed on a large scale it has solved many current networking problems.
When IP was defined , only a few computer networks has existed Then the designers decided to use 32 bits for an IP address because doing so allowed the Internet to include over a million networks. However, the global Internet is growing exponentially, with the size doubling in less than a year. Currently, two versions of the Internet Protocol (IP) are in use on the Internet. In some sense, there is a competition going on between these protocols, as they are not directly compatible, and network providers and users are being forced to determine whether to support one or both protocols for various network services. IP version 4
(IPv4) is the incumbent and currently has the most widespread usage for conventional Internet applications. IP version 6 (IPv6) is a large-scale re-design and reengineering of IPv4, based on many lessons learned as the
IPv4-based Internet grew and was used in unforeseen ways.
Hanumanthappa .J., Dos in Computer Science, University of
Mysore, Manasagangothri, Mysore, Karnataka .INDIA ( phone: +091-
821-2419552; fax: +091-0821-2510789,Email: hanums_j@yahoo.com )
Dr.Manjaiah.D.H., Reader, Mangalore University,
Mangalagangothri , Mangalore, Karnataka, INDIA. (phone: +091 - 0824 -
2287670; fax: +091 - 0824 - 2287424 Email: ylm321@yahoo.co.in )
Although it would seem obvious that IPv6 is a superior and valuable protocol to deploy, there is often considerable resistance to enabling IPv6 because Decision-makers have difficulty in seeing a business case for IPv6, unsure of how it can be less costly, more efficient, more productive, etc than the IPv4 status quo. Also, some analysts have propagated significant amounts of misinformation about
IPv6 over the last several years. The primary motivation for the defining a new version of IP arises from the address space limitation- larger addresses are necessary to accommodate continued growth of Internet. The secondary motivation for the changes in IP has arisen from the new
Internet applications. For example, an applications that deliver audio and video need to deliver data at regular intervals. In this paper we have also contrasted the various features of IPv4 and IPv6.
A. The serious problems of IPv4 are as follows
1. Insufficient number of unique “valid” addresses.
2. Routing tables at core are becoming unmanageably large. 3. Fixed length headers are not flexible enough for new functionality. 4. Packet size (and Practice of fragmentation) is inefficient. B. The next–generation IPv6 has some advantages over
IPv4 that can be summarized as follows
(i). Larger address space: An IPv6 address is 128 bits long.
Compared with the 32-bit address of IPv4, this is a huge
(296) increase in the address space.
(ii). IPv6 addressing: An IPv6 address consists of 16 bytes
(octets).It is 128 bits long.
To make address more readable, IPv6 specifies hexadecimal colon notation. In notation 128 bits are divided into eight sections, each 2 bytes in length. Two bytes in hexadecimal notation require four hexadecimal digits.
Therefore address consists of 32 hexadecimal digits with
T
every four digits separated by a colon. Although the IP address, even in hexadecimal format, is very long, many of the digits are zeros. In this we can abbreviate the address.
The leading zeros of a section can be omitted .Only the leading zeros can be dropped, not the trailing zeros. The below figure shows abbreviated IPv6 address.
C.Better header format: IPv6 uses a new header format in which options are separated from the base header and inserted, when needed, between the base header and the upper –layer data. This simplifies and speeds up the routing process because most of the options do not need to be checked by routers.
D. New options: Changes in the way IP header options are encoded allows for more efficient forwarding, less stringent limits on the length of options, and greater flexibility for introducing new options in the future.
E. Allowance for resource allocation: IPv6 is designed to allow the extension of the protocol if required by new technologies or applications.
F. Support for resource allocation: In IPv6, the type –of service field has been removed, but a mechanism called flow label has been added to enable the source to request special handling of the packet. This mechanism can be used to support traffic such as real-time audio and video.6.IPv6 enables addressing architectures that scale well in terms of the number of nodes and sub networks, the size of subnet works, and the degree of change within subnet works this includes typically-encountered cases where IPv4 becomes difficult to use robustly. Global routing tables in IPv6 are potentially much simpler than their IPv4 counterparts, and thus require lower memory and computational resources. In resource-constrained environments, IPv6 requir