Internet
Protocol Version 6 (IPv6) is a new suite of standard
protocols for the network layer of the Internet defined by IETF to
replace the current version of Internet Protocol version 4 (IPv4). IPv6
is also called as Next Generation Internet Protocol or IPng.
IPv6 is designed to be an
evolutionary step from IPv4. It is a natural increment to IPv4. It can
be installed as a normal software upgrade in internet devices and is
interoperable with the current IPv4. Its deployment strategy is
designed to not have any flag days or other dependencies. IPv6 is
designed to run well on high performance networks (e.g. Gigabit
Ethernet, OC-12, ATM, etc.) and at the same time still be efficient for
low bandwidth networks (e.g. wireless). In addition, it provides a
platform for new internet functionality that will be required in the
near future.
IPv6 describes rules for
three types of addressing: unicast (one host to one other host),
anycast (one host to the nearest of multiple hosts), and multicast (one
host to multiple hosts). Additional advantages of IPv6 are:
-
Options are specified
in an extension to the header that is examined only at the destination,
thus speeding up overall network performance.
-
The introduction of an
"anycast" address provides the possibility of sending a message to the
nearest of several possible gateway hosts with the idea that any one of
them can manage the forwarding of the packet to others. Anycast
messages can be used to update routing tables along the line.
-
Packets can be
identified as belonging to a particular "flow" so that packets that are
part of a multimedia presentation that needs to arrive in "real time"
can be provided a higher quality-of-service relative to other
customers.
-
The IPv6 header now
includes extensions that allow a packet to specify a mechanism for
authenticating its origin, for ensuring data integrity, and for
ensuring privacy.
IPv6 Features:
-
New header format
-
Large address space
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Efficient and
hierarchical addressing and faster routing infrastructure
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Stateless and stateful
address configuration
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Mobile support (Mobile
IPv6)
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Built-in network layer
security
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Better support for QoS
-
New protocol for
neighboring node interaction
-
Extensibility
Addressing
Format :
An IPv4 address is a 32-bit
value that's usually written in "dotted quad" representation, where
each "quad" represents a byte value between 0 and 255, for example:
127.0.0.1
This allows a theoretical
number of 2^32 or ~4 billion hosts to be connected on the Internet. Due
to grouping, not all addresses are available today.
IPv6 addresses use 128-bit
technology, which results in 2^128 theoretically addressable hosts.
This allows a really big number of machines to
be addressed, and it will fit all today's requirements plus PDAs, cell
phones, and even IP phones in the near future without any sweat. When
writing IPv6 addresses, they are usually divided into groups of 16 bits
written as four hex digits, and the groups are separated by colons. An
example is:
fe80::2a0:d2ff:fea5:e9f5
This shows a special thing
-- a number of consecutive zeros can be abbreviated by a single "::"
once in the v6 number. The above address is thus equivalent to fe80:0:00:000:2a0:d2ff:fea5:e9f5
-- leading zeros within groups can be omitted.
Mobile IPv6:
Mobile IPv6 allows an IPv6
node to be mobile - to arbitrarily change its location on an IPv6
network - and still maintain existing connections. When an IPv6 node
changes its location, it might also change its link. When an IPv6 node
changes its link, its IPv6 address might also change in order to
maintain connectivity. There are mechanisms to allow for the change in
addresses when moving to a different link, such as stateful and
stateless address autoconfiguration for IPv6. However, when the address
changes, the existing connections of the mobile node that are using the
address assigned from the previously connected link cannot be
maintained and are ungracefully terminated. The key benefit of Mobile
IPv6 is that even though the mobile node changes locations and
addresses, the existing connections through which the mobile node is
communicating are maintained.
IPv6
Resources:
IPv6
Forum
IPv6 Working Group
IPv6
Howto's
IPv6 Tutorial
IPv6
Related specifications
IPv6
DNS Setup
The
IPv6 Mess
Why you want IPv6
Current
status of allocaitons of IPv4 Addresses
Free
IPv6 Tunnel Broker
IPv6 networking FAQ
IPv6
Tools
Getting started with IPv6
IPv6
Resource centre
Mobile
IPv6 for Linux
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