Why using Ipv6?
IPv4 has only about 4.3 billion addresses available—in theory, and we know that we don’t even get to use all of those. There really are only about 250 million addresses that can be assigned to devices.
There are a lot of reports that give us all kinds of numbers, but all you really need to think about to convince yourself that I’m not just being an alarmist is the fact that there are about 6.5 billion people in the world today, and it’s estimated that just over 10 percent of that population is connected to the Internet, which means will run out of them, and it’s going to happen within a few years.
That statistic is basically screaming at us the ugly truth that based on IPv4’s capacity, every person can’t even have a computer—let alone all the other devices we use with them. I have more than one computer, and it’s pretty likely you do too. And I’m not even including in the mix phones, laptops, game consoles, fax machines, routers, switches, and a mother lode of other devices we use every day! So I think I’ve made it pretty clear that we’ve got to do something before we run out of addresses and lose the ability to connect with each other as we know it. And that “something” just happens to be implementing IPv6.
The problem of IPv4 address exhaustion was recognized in the early 1990s, when various experts made projections showing that if the increasing rate of the allotment of IPv4 addresses continued, the entire address space could be depleted in just a few short years. A newversion of IPknown in the development stage as IP Next Generation or IPng, and which is now IPv6was the proposed solution. But it was
recognized that developing the new standards would take time, and that a short-term solution to IPv4 address depletion also was needed.
That short-term solution was Network Address Translation (NAT), which allows multiple hosts to share one or a few public IP addresses. Behind the NAT device, private IP addresses are used.
NAT has been so successful in slowing IPv4 address depletion, and has become such a standard part of most networks, that to this day many still question the need for a new version of IP. But the widespread use of NAT has changed the open, transparent, peer-to-peer Internet into something much more like a huge collection of client-server networks. Users are seen as being connected around the "edge" of the Internet, and services flow out to them.
Although most of the IPv6 standards were completed years ago, it is only recently that serious interest in migrating from IPv4 to IPv6 has been shown.
There are two fundamental drivers behind the growing recognition of the need for IPv6.
The first is widespread vision of new applications using core concepts such as mobile IP, service quality guarantees, end-to-end security, grid computing, and peer-to-peer networking. NAT stifles innovation in these areas, and the only way to get NAT out of the way is to make public IP addresses abundant and readily available.
The second fundamental driver for IPv6 is the rapid modernization of heavily populated countries such as India and China. A compelling statistic is that the number of remaining unallocated IPv4 addresses is almost the same as the population of China: about 1.3 billion. With its aggressive expansion of its Internet infrastructure, China alone in the near future will represent an unsupportable pressure on an already strained IPv4 address pool. In India, with a population size close to China's, 4- and 5-layer NAT hierarchies exist just to support the present demands for IP addresses.
IPv6 replaces the 32-bit IPv4 address with a 128-bit address, making 340 trillion trillion trillion IP addresses available.
That number will meet the demands for public IP addresses, and answer the needs of the two fundamental drivers discussed here, well into the foreseeable future.
Benefits using Ipv6?
IPv6 includes the following enhancements over IPv4:
■ Expanded address space—IPv6 uses 128-bit addresses instead of the 32-bit addresses in IPv4.
■ Globally unique IP addresses—The additional address spaces allow each node to have a
unique address and eliminate the need for NAT.
■ Fixed header length—The IPv6 header length is fixed 40 bytes, allowing vendors to improve
switching efficiency, routers do not need to recalculate a header checksum for every packet
■ Address autoconfiguration—This capability provides for dynamic assignment of IPv6
addresses. IPv6 hosts can automatically configure themselves, with or without a Dynamic
Host Configuration Protocol (DHCP) server (Plug & play).
■ Support for labeling traffic flows—Instead of the type-of-service field in IPv4, IPv6 enables the labeling of packets belonging to a particular traffic class for which the sender requests special handling.
This support aids specialized traffic, such as real-time video& traffic flow. There are several advantages to differentiating flows, from providing a finer-grained differentiated class-of-service treatment to ensuring, when balancing traffic loads across multiple paths, that packets belonging to the same flow are always forwarded over the same path to prevent possible reordering of packets. As of this writing, however, the complete specification of how to use the flow label field is still being debated, and routers currently ignore the field.
■ Mobility and security: Mobility and security help ensure compliance with mobile IP and IPsec standards functionality. Mobility enables people to move around in networks with mobile network devices—with many having wireless connectivity. The standard enables mobile devices to move without breaks in established network connections. Because IPv4 does not automatically provide this kind of mobility,You must add it with additional configurations. In IPv6, mobility is built in (any cast), which means that any IPv6 node can use it when necessary.
IPsec is mandatory in IPv6. IPsec is enabled on every IPv6 node and is available for use. The availability of IPsec on all nodes makes the IPv6 Internet more secure. IPsec also requires keys for each party, which implies a global key deployment and distribution.
■ Maximum transmission unit (MTU) path discovery—IPv6 eliminates the need to
fragment packets by implementing MTU path discovery before sending packets to a
destination, routers doesn’t need to do fragmentation any more.
■ Site multihoming—IPv6 allows multihoming of hosts and networks to have multiple IPv6
prefixes, which facilitates connection to multiple ISPs.
Ipv6 Address Representation
Rather than using dotted-decimal format, IPv6 addresses are written as hexadecimal numbers with colons between each set of four hexadecimal digits (which is 16 bits).
So ipv6 is a 16bit-eight coloned-hex ,The format is x:x:x:x:x:x:x:x, where x is a 16-bit hexadecimal field.
A sample address is as follows:
Fortunately, you can shorten the written form of IPv6 addresses. Leading 0s within each
set of four hexadecimal digits can be omitted, and a pair of colons ( :: ) can be used, once
within an address, to represent any number of successive 0s but once in the address
http://[ 2035:1:2BC5::87C:0:A ]/default.html
Consequently, some countries, such as Japan, are aggressively adopting IPv6. Others, such as those in the European Union are moving toward IPv6, and China is considering building pure
IPv6 networks from the ground up.
As of October 1, 2003, even in North America, where Internet addresses are abundant, the U.S. Department of Defense (DoD) mandated that all new equipment purchased be IPv6-capable. In
fact, the department intends to switch entirely to IPv6 equipment by 2008.
Have attached a word file, with more details about the IPv6 Addressing types & NDP, with routing protocols config.
use it in your studying.
Hope it might help.