What is IPv6? (by IGRP group 2008 - IPv6)

Introduction

In Mid-1970’s ARPANET introduced the Internet Protocol (IP) as a mean of communication from one computer to the other in interconnected networks. Internet Protocol (IP) is one of the fundamental building blocks of the Internet. The IP supports the network by providing a unique address to the various hardware equipments (e.g computers, routers and smart phones) on a network.

By early ‘90’s, success of the Internet and its fast growth led to less and less addresses, and an increase in memory space required for storing the addresses of more and more gadgets connected on the Internet. A solution for this problem was obvious, a new addressing system, which provided enough addresses that would never run out, to succeed IPv4. Though there were other versions, some for other purposes, like IPv5, in 1995 IP-The Next Generation (IPng) or popularly known as IPV6 was birthed. Details for the first specification of this new protocol are in RFC 1883.


Brief Technical Description

The IPv6 address is 128 bits in size compared to IPV4 version which is 32bits. It is represented with hexadecimal numbers in eight groups of four as follows:

IPV4: HHHH : HHHH : HHHH : HHHH (172.29.7.10)

IPV6: HHHH : HHHH : HHHH : HHHH : HHHH : HHHH : HHHH : HHHH (2012:0000:0000:0000:0004:0500:200B:23B6)

The long IPv6 addresses can be also represented in short form by :

* Supressing leading 0, so that IPv6 address above can be written as 2012:0:0:0:4:500:200b:23B6
* Using double colon to suppress 0s so that the address above can also be written as 2012::4:500:200B:23B6

IPv4 Header:

IPv6 Header:

Depletion of IPv4 and Need for IPv6

IPV4 is still the most commonly used version today. It has proven to be robust, implementable and interoperable, and has stood the test of scaling networks to a global utility, the size of today's Internet. Nevertheless, in the creation of IPv4 the following needs were overlooked:

* Exhaustion of address space

* The need for simpler network configuration

* Security on the IP level

Now nearly twenty years later, IPv4 continues to serve our Internet needs howbeit beginning to reach the limit of its effectiveness. There is a noticeable shortage of IPv4 addresses in the wake of an ever increasing need to add new equipment to the Internet.

An article posted on the LACNIC website in June 2007 reported that as a response to the forecasts prepared by several investigators indicating that by the year 2011 the central pool of version 4 (IPv4) Internet addresses could be completely depleted, LACNIC launched a regional campaign so that all the region’s networks would be adapted to the new version 6 of the protocol (IPv6) before January 1st, 2011. This approach has been followed by several other regional blocks and/or individual countries.

To ensure a smooth transition, IPv6 is only expected to gradually replace IPv4, with the two coexisting for a number of years during a transition period. The IPv4 addresses depletion implies the ineluctable transition to the new protocol IPv6. Experts have been informing and warning that IPv4 addresses are on they way to finish, some foresee the possible dates are about 2010 – 2011, based on the low amount of IPv4 addresses unallocated (15%) and consumption trends . Latest figures from the Internet Numbers Authority (IANA) for example, indicate that only about 15 percent of IPv4 addresses remains unallocated. The IPv6 Forum maintains a count down to IPv4 address exhaustion. The growth in use of the Internet and more specifically use of IP address was relatively low at the time when the Internet was established in the 1980s. There was a marked increase in the early 1990s particularly as the Internet was adopted by the academic and research sector, however the shift from class-based to classless address architecture reduced the rate of consumption of IP addresses. In recent years however, the demand levels for addresses has accelerated again due to factors like development of new Internet based applications and the increasing number of people using it.

However, some question the need for urgency in transition. They argue that even if the free pool of IPv4 addresses is depleted, the Internet would keep on ticking. The need for more addresses, and hence IPv6, is the prerequisite for its adoption. Tim Rooney of BT INS, an organisation that sells IP address management products explains the perception of many users reluctant to make the transition as, “IPv4 addresses aren’t perishable. Once I have an IPv4 address, I have it. So unless or until I am expanding my network and I’m demanding more public IP address space, I probably don’t perceive IPv4 address depletion as an issue.’’

According to a BT INS survey of 310 IT professionals, conducted in December 2007, only 16% consider IPv4 address depletion "a huge concern that has or will soon force us to migrate to IPv6.’’ The survey found that the perception was that while IPv6 has a number of advantages including security and auto configuration, none of these is compelling enough as yet for people to move. IPv4 address depletion would be the primary reason, but in areas that still have availability of IPv4, this argument doesn’t hold.

Policy proposals on the extension of IPv4 address life and allocation of the remaining IPv4 address pool are being discussed in each Regional Internet Registry (RIR) policy public forum and its process. In general terms predictions are: using more NATs in order to IPv4 networks persist; the scarcity of IPv4 will possibly open trading markets of these resources; IPv6 adoption. Although there are proposals and efforts to postpone the date when IPv4 addresses resources deplete, IPv6 implementation and deployment is unavoidable and essential because firstly using NAT is expensive and does not give the innovation possibility that IPv6 does (mainly, more and more addresses !!). The Internet Services Providers (ISP) have to face the cost that comes with use of such mechanisms, affecting their profits.


Some Advantages of IPv6

It seems that the primary motivation to develop IPv6 was to increase the number of IP addresses. IPv6 has a much larger address space than IPv4, which provides flexibility in allocating addresses and routing traffic. IPv4 uses 32 bits for addressing, that allows for theoretically around 4 billion addresses while IPv6 uses 128 bits and thus allowing a far much larger address space around 340 sextillion addresses (wow !!).


Some of the main advantages of IPv6 are as follows:


New Header Format

The IPv6 header has a new format that is designed to keep header overhead to a minimum. This is achieved by moving both non-essential fields and optional fields to extension headers that are placed after the IPv6 header. The streamlined IPv6 header is more efficiently processed at intermediate routers.
IPv4 headers and IPv6 headers are not interoperable. IPv6 is not a superset of functionality that is backward compatible with IPv4. A host or router must use an implementation of both IPv4 and IPv6 in order to recognize and process both header formats. Even IPv6 addresses are four times as large as IPv4 addresses, new IPv6 header is only twice as large as the IPv4 header.


Larger Address Space

IPv6 has 128-bit (16-byte) source and destination IP addresses. Although 128 bits can express over 3.4×1038 possible combinations, the large address space of IPv6 has been designed to allow for multiple levels of subnetting and address allocation from the Internet backbone to the individual subnets within an organization.
This feature makes no need to use of some traditional technics found in IPv4 implementation like NAT.


Efficient Routing Infrastructure

IPv6 global addresses used on the IPv6 portion of the Internet are designed to create an efficient, hierarchical, and summarizable routing.
We may say that this is not a great deal, as this may be achieved in IPv4 also; but with a better distribution and allocation IPv6 policy it may lead to big improvements.


Stateless and Stateful Address Configuration

IPv6 supports both stateful address configuration, such as address configuration in the presence of a DHCP server, and stateless address configuration (address configuration in the absence of a DHCP server). With stateless address configuration, hosts on a link automatically configure themselves with IPv6 addresses for the link (called link-local addresses) and with addresses derived from prefixes advertised by local routers. Even in the absence of a router, hosts on the same link can automatically configure themselves with link-local addresses and communicate without manual configuration.


Security

Support for IPsec is an IPv6 protocol suite requirement. This requirement provides a standards-based solution for network security needs and promotes interoperability between different IPv6 implementations. Here we must point out that this does not make IPv6 more secure than IPv4 (this is a common false argument); it means that IPv6 provides tools for making security easier than in an IPv4 scheme.


Better Support for Prioritized Delivery

New fields in the IPv6 header define how traffic is handled and identified. Traffic identification using a Flow Label field in the IPv6 header allows routers to identify and provide special handling for packets belonging to a flow, a series of packets between a source and destination. This extends the traditional function of the TOS field on IPv4 header.

New Protocol for Neighboring Node Interaction

The Neighbor Discovery protocol for IPv6 is a series of Internet Control Message Protocol for IPv6 (ICMPv6) messages that manage the interaction of neighboring nodes (nodes on the same link). Neighbor Discovery replaces the broadcast-based Address Resolution Protocol (ARP), ICMPv4 Router Discovery, and ICMPv4 Redirect messages with efficient multicast and unicast Neighbor Discovery messages.


Extensibility

IPv6 can easily be extended for new features by adding extension headers after the IPv6 header. Unlike “Optionals” in the IPv4 header, which can only support 40 bytes of options, the size of IPv6 extension headers is only constrained by the size of the IPv6 packet.


Autoconfiguration

IPv6 provides an easier and simple connection between nodes, more efficient mobility (suitable for our modern “mobile” life, for 3G wireless applications and others) and extensibility (it enables to add new characteristics in a easy and infinite manner) ,etc. With a good implementation the economic benefits are long-term.


New Opportunities

All IPv6 features create opportunities for developers everywhere in the world, including in developing countries. It opens a new horizon for developing new applications that take advantage of features offered by IPv6 (middle-sized businesses) giving them the opportunity for innovation and captioning new and more segments of the market. Mobile phone companies will expand their products; it opens the scope of new Internet products and services of communications field; it reduces costs thanks to a greater efficiency. Therefore the new protocol contributes to enhance the technological and economic country development.


Current Intake of IPv6

Some IPv6 adoption has been registered particularly in Europe and in the Asia-Pacific. However, globally it could be said that we are in the early days of IPv6 deployment. Comparing the allocations made around the world over several years, the trend does not show massive deployment or a huge growth.

Most of the current publicly available data in IPv6 current approximate utilization is result of the CAIDA and ARIN (American Registry for Internet Numbers) IPv6 Survey (Results provided on October 15,2008) and Global and regional statistics of the RIRs (Regional Internet Registries).

ipv6_survey_summary.pdf

The CAIDA-ARIN IPv6 Survey, which had 1100 respondents around the world, came up with the results summarized below:

* 83% of the entities that are currently using IPv6 are profit organizations, the majority of which are commercial businesses. 17% are non- profit organizations, in which the biggest user is Education sector, with 54%, followed by 8% for Research and development then 5% Government and others.
* Concentration by size organization: Small organisations are leading in the use of IPv6.
* Concentration by geographic area: Europe, allocated by RIPE NCC (Regional Internet Addresses Registry for Europe, the Middle East and parts of Central Asia); followed by the allocations made by APNIC (RIR of Asia Pacific region) and ARIN.
* Strong motivation to adopt IPv6: Most of the organizations are using IPv6 because they "want to be on top of the game".
* Most remarked barriers for IPv6: Dual support for IPv4 and IPv6 at the application level (Very Large organizations); Lack of IPv6 expertise (Medium organizations) and Lack of support from transit providers (Small organizations).
* Why other organizations turned off IPv6: Lack of user demand, technical problems and finances.

(Any comments here ??)


Facts and Figures

The following chart shows the distribution of the IPv6 blocks that have already been allocated among the different RIRs (expressed in number of /32s) as of October 2008.

RIPE 45.7%
APNIC 33.5%
ARIN 20.4%
LACNIC 0.4%
AFRINIC 0.1%

Currently it is difficult to measure the amount of IPv6 traffic due to the fact that so much of it is tunnelled inside of IPv4 mostly from end users.

The quantity of IPv6 addresses actually allocated does not accurately reflect the utilization of IPv6 either. In theory they become used at some point after the allocation, but they may not appear in the routing table.

The chart below shows the number of routing entries in the global IPv6 routing table during the period from 1 January 2004 to March 2008. It shows a period of steady growth across 2004 and 2005, and then a significant downturn in the first half of 2006. Then it shows a pick up from mid-2007, with a 33% growth in the number of routing entries in the first mid-2008.

Geoff Houston web site, APNIC. “IPv6 Deployment: Just where are we?”

The real current level of IPv6 consumption on the Internet, in terms of services remains quite small. However, the relative use of IPv6 in today's Internet as compared to IPv4 is increasing, although IPv6 is still a very small proportion of the IPv4 Internet.

One possible measure of IPv6 deployment in ISPs is the number of IPv6 address blocks (prefixes) seen in the routing table in comparison with the number of autonomous systems (ASs - roughly equivalent to ISPs) in a region. In this case, AfriNIC, (the Regional Internet Registry for Africa and parts of the Indian Ocean), has a higher proportion of networks in its region announcing IPv6 addresses than the others. "Africa also has a smaller deployed base but IPv6's size is designed to support exactly the kind of network growth that highly populated areas, like Africa and Asia will see as their deployed base grows in the next few years", as Leo Vegoda of ICANN remarks in his article (CIRCLE ID. Sep.29,2008).

References

Paul Wilson’s presentation, CEO of APNIC, in ICANN meeting in New D...

ARIN & CAIDA IPv6 Survey, October 2008

Global IPv6 statistics IPv6 Portal site

CIRCLE ID. “Which Region is Taking the Lead in IPv6 Deployment?” By...

Geoff Houston web site, APNIC. “IPv6 Deployment: Just where are we?”

http://www.kh.refer.org/cours_en_lignes/cours_reseau/Page/chap5_lec...

http://www.u-bourgogne.fr/LE2I/o.togni/ipv6.pdf (University of Bourgogne in France)

ICANN Fact Sheet IPv6 – The Internet’s vital expansion October 2007

Jordi Palet, IPv6 Legal Aspects of the new Protocol Pages 17-20, Consulintel/ECIJA/University of Murcia UMU (Spain)

Ken Cheng, Foundry Networks, presentation the Business Reality of IPv6

Introduction to IP Version 6, Microsoft Windows Server System, January 2007