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Technology - IPv6 -The Next Generation Internet Protocol: Part II
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Krishnamoorthy Arvind 04/14/2005
This two-part article presents IPv6,
the next generation of the protocol that powers the Internet. The first
installment of the article introduced IPv6 and discussed its raison
d’etre. The second installment provides a overview of some of its
features and benefits, and the market outlook for IPv6.
IPv6 is the next generation Internet Protocol that will eventually
replace IPv4, the current generation Internet Protocol that is over a
quarter of a century old. The design of IPv6 incorporates various
lessons learned from the IPv4 experience, and IPv6 therefore offers a
number of technical benefits over the incumbent IPv4. Some of these
benefits are listed below, and also discussed in excellent books
available on the subject (such as “Understanding IPv6” by Joseph
Davies, and “IPv6 Essentials” by Silvia Hagen). · IPv6 introduces processing efficiencies.
IPv6 was designed with lessons learned from IPv4 in mind, and sports a
more streamlined design. It uses brief, fixed size headers that result
in more efficient processing and forwarding. Imagine how uniform
envelopes with no frills can speed up processing inside a post office.
· IPv6 allows smaller routing tables in the Internet core.
IPv6 addresses are structured in a hierarchical manner. This reduces
the number of routes that packet switches in the core of the Internet
need to handle, thereby reducing the complexity of core routing
devices. Imagine a postal sorting center that sorts International mail
as it leaves the country into destination-specific pigeonholes. IPv6
routing is roughly analogous to the sorting system, where the
pigeonholes correspond to the different countries in the world. IPv4
routing is like the sorting system, where some of the pigeonholes
correspond to countries, some to individual provinces of some
countries, and some pigeonholes even to individual towns of other
countries. Clearly, IPv6 routing corresponds to a more scaleable
system.
· IPv6 enables end-to-end communications.
A number of exciting Internet applications such as telephony, video
conferencing, and shared whiteboards are peer-to-peer applications
(where all participants have equal peer status); as opposed to
client-server applications such as web browsing or music downloading
(where a server provides content to a client that requests it). Network
Address Translation (NAT), which is one of the address conservation
technologies in use to prolong the life of IPv4, is not friendly to
peer-to-peer applications. IPv6 makes it simpler to implement these
applications by enabling direct end-to-end communications.
· IPv6 comes with security and mobility built into it.
IPv6 was designed with security and mobility in mind, issues that
didn’t receive much attention when IPv4 was originally designed. When
you send a packet of information over the Internet, you want to be able
to trust that the transaction is safe. For example, you want to be sure
that nobody but the receiver can read its contents (privacy), the
contents don’t get modified while in transit (integrity), and that
nobody else can pretend to be you (authentication). Security and
mobility features were added on to IPv4 as an after thought after
deployment. Building in these features into the design of IPv6 has
resulted in a scalable, robust implementation with fewer restrictions.
· IPv6 offers features for better quality of service.
Quality of service such as minimizing delay and jitter is an important
requirement for multimedia traffic such as audio and video. IPv6 packet
headers include fields that support the realization of quality of
service even when the content is encrypted.
· IPv6 allows stateless auto-configuration of addresses.
IPv6 provides mechanisms for devices to self-configure automatically
with IPv6 addresses when they connect to a network, without the need
for any special servers. IPv6 spans numerous other technical
concepts not covered here including Internet Control and Message
Protocol, Neighbor Discovery, Co-existence and Migration mechanisms,
Tunneling, Unicast and Multicast Routing, Mobility, etc. An inquisitive
reader should have no problem in googling all this information out of
the web! You can also check out the web pages of the Internet
Engineering Task Force
(http://www.ietf.org/html.charters/ipv6-charter.html), the body tasked
with standardizing various aspects of IPv6. What is the
market outlook for IPv6? In the late 1990’s, the rapid depletion of
IPv4 addresses seemed to predict the imminent deployment of IPv6.
However, the adoption of certain IPv4 address conservation technologies
eliminated the economic impetus to urgently adopt IPv6, and pushed the
need for IPv6 well into the second decade of this century. However,
IPv6 has recently received a fresh impetus with the US Department of
Defense’s decision to make a complete transition to IPv6 in the next
few years, and mandating immediate IPv6-readiness in its equipment
procurement requirements. Prominent vendors including Cisco Networks,
Enterasys Networks, Juniper Networks, and Microsoft have IPv6
offerings. The need generated in IPv4 address-deprived countries such
as Japan, China, and India is also fueling near-term interest. The
Indian Union Minister for Information Technology, Mr. Dayanidhi Maran,
proposed a 10-point agenda for Indian IT last year, which includes
migration to IPv6 in India by 2006. These events, along with the
proliferation of peer-to-peer applications, and the continuing
explosion in the number and types of Internet-capable devices (often
with mobility and always-on requirements) are likely to drive the
deployment of IPv6 in the near term. The actual pace of deployment will
be determined by economic factors that influence the rate of technology
transition, and by the elasticity left in the incumbent IPv4 technology
to creatively accommodate demands placed on it without running out of
steam. The Internet has evolved into a key driver of
world-wide economic expansion in the 21st century. Continued growth of
the Internet will fuel the continued growth of the global economy. The
expected gradual deployment of IPv6 should help remove any roadblocks
in the continued expansion of the Internet. (Dr. K. Arvind received his PhD in Computer Science from the University of Massachusetts at Amherst, and his B.Tech in Electronics Engineering from the Indian Institute of Technology, Madras. In addition to active involvement in software R & D, he has published technical papers, participated in standards efforts, and spoken at a number of conferences. He has served in various companies in the Networking industry including Digital Equipment Corporation, 3Com, and Tenor Networks. He currently serves as a Consulting Engineer/Architect at Enterasys Networks, Andover, MA, and can be reached at karvind@enterasys.com. )
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