INTRODUCTION:

 

The Internet
operations, engineering and research communities are putting significant
attention into a relatively new Version (actually 15 years old) of the Internet
Protocol – IP version 6 (IPv6) designed to solve several architectural
limitations of the existing IPv4 protocol. The most essential characteristic of
IPv6 is that it has provides orders of magnitude more address space than the
world’s foreseeable IP connectivity needs. IPv6 has become especially pertinent
in the last two years because the global Internet address allocation
architecture relies on the presence of a free pool of IP addresses to allocate
to sites operating Internet infrastructure. The Internet Assigned Numbers
Authority (IANA) exhausted its unallocated address pool in February 2011, and
the Asia-Pacific region (represented by the AP-NIC RIR) followed suit in April
2011. The remaining RIRs too are expected to run out of unallocated addresses
in the next few years. This exogenous pressure from IPv4 address scarcity has
driven widespread adoption of IPv6 into modern operating systems and network
equipment. Prior to implementation of IPv4, engineers and scientists
working on ARPANET debated on the length of an IP address. The debate was
between 32-bit and 128-bit address lengths. 
The resulting scarcity of IPv4 address blocks leads to gradual depletion
of IPv4 address space. In order to save and reuse the address blocks, service
providers (SP) resort to mechanisms like multiple layers of Network Address
Translation (NAT). The more ideal approach to solve the issue of address
scarcity facing the networking industry is to move towards the IPv6 addressing
scheme.

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 IPv6 provides 3.4 x 1038 addresses and comes
with other additional improvements. First, it provides increased efficiency in
routing. Second, it provides faster packet processing. Third, it supports
multicast thereby overpowering the hassles of broadcasting packets. Fourth, it
avoids network address translation (NAT), therefore, proves to be more robust
3.

 

 

 

 IPv6 adoption has been slow and faces numerous
obstacles. First, there is no true financial driver for companies. The
exhaustion of IPv4 address space has been advertised for years and the industry
has developed technology to extend IPv4 address usage. The most popular of
these technologies is Network Address Translation (NAT). NAT helped to push out
the exhaustion of IPv6 by roughly a decade. This has bought time for IPv6 to
mature further.

During this year’s world IPv6 day, the goal is to
enable approximately one percent of the Internet with IPv6 support. This is not
an estimate of actual IPv6 traffic. The experts expect IPv6 traffic to increase
exponentially in the coming years.

 

Scope
& Assumptions :

 

This
research paper comments on some of the common transition technologies that
would facilitate the co-existence of both IPv4 and IPv6 addresses in the coming
years. This research paper provides a cable provider-centric approach in
describing the transition technologies. Our research paper only discusses
existing co-existence technologies and tries to determine the advantages and
disadvantages in the transition techniques we’ve researched. Additionally, our
research is focused on those technologies being considered for deployment by
our interviewees. Those technologies are Large Scale Network Address
Translation (LSN), Dual Stack, IPv6 rapid deployment (6rd), Dual Stack Lite
(DS-Lite), and NAT64. Our observations and conclusions are based on our
interactions with the industry experts in IPv6 as well as academic research.

Our research paper follows certain assumptions. The
first assumption is that additional IPv4 addresses will not be available in the
immediate future as a result of IPv4 exhaustion. Secondly, that transitioning
to IPv6 or implementing IPv4 extension technology are the only solutions that
will solve the problem of IPv4 address exhaustion.

 

 

 

3
IPv6 Adoption Strategies & Technologies

Native
Dual Stack:

 

The
Dual Stack implementation consists of a network topology that provides the
ability to route and forward IPv4 and IPv6 packets. This functionality can be
at just the customer’s environment, on the SP’s network core, its edges, or
some other combination. The dual stack approach can be deployed across the
entire network or in regional areas but in order for the dual stack approach to
work, protocol continuity for packets in transit must be met.

 

Translation
Technologies :

 

Translation technologies translate one protocol into
another protocol. This facilitates interoperability between the protocols.
There are many transitional technologies. In this paper, we focus on NAT64 as
most of the interviewees cited this translation technology the most.

 

Further
Research :

 

This research paper offers a broad scope of IPv4/IPv6
co-existence technologies ideal for a cable provider network. There are
numerous options for further research. The scenarios (2, 3 and 7) that were not
discussed are areas that require further research. In particular further research
on technologies that allow IPv4 hosts to communicate with IPv6 hosts and
services is needed. Additionally, each of the recommended technologies could
also be further researched by exploring performance and implementation issues.

 

Specification
for the new version of IP (v6):

 

The new
version of the IP protocol that was to be developed required the following main
objectives: extend the IP address space, correct the defects of IPv4 standard
and improve its performance as much as possible, anticipate future needs, and
promote innovation by simplifying the implementation of functional extensions
to the protocol These objectives were constrained, however, in that they had to
retain the principles that made IPv4 such a success”end-to-communication”,”robustness”,
and “best effort”.

 

What’s
new with IPv6?

 

First of
all, IPv6 provides a much larger address space than IPv4, with the transition
from 32-bit coding of IPv4 addresses (4.3 billion addresses) to 128-bit coding
of IPv6 addresses (3.4 1038, or 340 billion, billion, billion, billion
addresses). As a result, IPv6 is seen as an “enabler”, capable of
stretching our imagination. It is also an opportunity to restore the “end
to end” communication model, one of the foundations of IPv4 that was
shaken by the massive influx of NATs. In addition, IPv6 provides a new form of
autoconfiguration,  known as
“stateless” for hosts. For a host, this mechanism consists in
automatically building a local address for it to communicate with its
neighbours, and then to build a global IPv6 address on the basis of the
information announced by a local router on the network link. The stateless
au-configuration mode is in addition to the existing “stateful”
auto-configuration mode, covered by the Dynamic Host Configuration Protocol
(DHCP). Finally, IPv6 enables better integration of multicasting and better
support for functional

extensions,
by encapsulating them in dedicated optional headers, such as those for security
or mobility.

 

The
integration of IPv6: how, who and where?

 

The
integration of IPv6 is a gradual, collective initiative, for which all the
players in the network are responsible, each according to their own roles and
tasks. There will be no D-day for a sharp ‘switchover’ to IPv6. Before deciding
how this should be carried out, the following questions have to be asked: what
is to be done, by whom, and where? Let us start with what everyone should do on
their own computer, i.e. upgrade / update the operating system and network
applications they use, to make them compatible with IPv6. For most operating
systems and typical network applications, there is almost nothing else to do,
since the recent versions handle IPv6 properly. However, unless you are an
administrator of a large network, in general you will not have to handle all of
these issues at once. In other words, you can usually take care of your
business and ask the other players later to take charge of theirs, especially
when you do not depend on them for yours! Even if you do manage a large network
with multiple responsibilities, there is no point in doing everything at the
same time, but gradually after a serious task of prioritisation and planning

 

Research
Question

 

The
need of the hour is to enable IPv6 capabilities on all existing networks.
However, IPv4 networks cannot upgrade to IPv6 networks immediately. This is
partially due to the perception of the technical immaturity of IPv6 as compared
to IPv4. Also, service providers are highly risk-adverse and are not receptive
to new changes so instantly. Additionally, there is a lack of IPv6 awareness.
The technical incompatibilities to convert all the network devices to 2 .

understand IPv6 instantly is another issue
that must be met. These factors lead us to look for alternatives that support
co-existence of IPv4 and IPv6 addressing schemes in networks 4.

The deployment of IPv6 is a phenomenon that has
started and is set to grow further in the years to come. There are many issues
and obstacles to achieve 100% IPv6 networks directly. Therefore, this paper
focuses on the transitional technologies and strategies required to achieve
IPv4-IPv6 co-existent networks.

 

EVOLVING
STRUCTURE OF IPV4 AND IPV6 TOPOLOGIES:

 

Similar to
our belief that the composition of a maturing IPv6 topology should look more
like the IPv4 topology, we also expect a convergence to occur between the best
AS path between a given pair of in IPv4 and IPv6. An-other reason to compare
IPv4 and IPv6 AS path congruity is its correlation with performance. In Section
7 we show that IPv6 data plane
performance is worse than IPv4 when the AS paths differ, but
when the AS paths are the same, IPv6 performance is comparable to that of
IPv4. Improved congruity between
IPv4 and IPv6 paths seem to improve

IPv6
performance, which is likely to further promote IPv6 deployment. To explore
trends in congruity between IPv4

and IPv6
paths, we first calculate the fraction of AS paths from a given vantage point (VP)
toward dual-stacked origin ASes (i.e., ASes that advertise both IPv4 and IPv6
prefixes) that are identical in IPv4 and IPv6. If there are multiple IPv4 or
IPv6 AS paths available between a given VP and an origin AS, we report it
having an identical AS path if any of the paths are the same.

 

EVOLVING
DYNAMICS OF IPV4 AND IPV6 INFRASTRUCTURE:

 

Continuing to
explore our hypothesis that a maturing IPv6 network should look more like the
IPv4 network, we compare the evolution of routing dynamics in IPv4 and IPv6. In
particular, we focus on the evolution of update churn, correlation between the
update churn seen from different vantage points, path exploration, and
convergence times in IPv4 and IPv6. We focus on these metrics for the following
reasons. First, we hypothesize that both IPv4 and IPv6 should show a similar
relation between update churn and the size of the underlying topology. Second,
due to bussness relationships and dense interconnection among ASes,churn
becomes localized, and each vantage point does not see the same set of routing
events. Consequently, correlation between update churn seen at different
vantage points can serve as a measure of the maturity of the underlying network
and business relationships. Finally, previous work has shown that end-to-end
delays and loss rates are significantly higher during routing events. It is
thus useful to compare the extent of path exploration and routing convergence
times during routing events. If these metrics are significantly worse in IPv6
as compared to IPv4, then it could deter the adoption of IPv6.

 

 

Features of IPv6

IPv6 is a powerful
enhancement to IPv4 with features that better suit current and foreseeable
network demands, including the following:

·        
Larger
address space—IPv6
addresses are 128 bits, compared to IPv4’s 32 bits. This larger address
space provides several benefits, including: improved global reachability and
flexibility; the ability to aggregate prefixes that are announced in routing
tables; easier multihoming to several Internet service providers (ISPs);
autoconfiguration that includes link-layer addresses in the IPv6 addresses for
“plug and play” functionality and end-to-end communication without
network address translation (NAT); and simplified mechanisms for address
renumbering and modification.

·        
Simplified
header—A
simpler header provides several advantages over IPv4, including: better routing
efficiency for performance and forwarding-rate scalability; no requirement for
processing checksums; simpler and more efficient extension header mechanisms;
and flow labels for per-flow processing with no need to examine the transport
layer information to identify the various traffic flows.

·        
Support
for mobility and security—Mobility
and security help ensure compliance with mobile IP and IP security (IPsec)
standards.

Mobility enables people to move
around in networks with mobile network devices, with many having wireless
connectivity. Mobile IP is an Internet Engineering Task Force (IETF) standard
available for both IPv4 and IPv6 that enables mobile devices to move without
breaks in established network connections. Because IPv4 does not automatically
provide this kind of mobility, supporting it requires additional
configurations.

In IPv6, mobility is built in,
which means that any IPv6 node can use it when necessary. The routing headers
of IPv6 make mobile IPv6 much more efficient for end nodes than mobile IPv4
does.

IPsec is the IETF standard for IP
network security, available for both IPv4 and IPv6. Although the functions are
essentially identical in both environments, IPSec is mandatory in IPv6. IPSec
is enabled and is available for use on every IPv6 node, making the IPv6
Internet more secure. IPSec also requires keys for each device, which implies
global key deployment and distribution.

·        
Transition
richness—There
are a variety of ways to transition IPv4 to IPv6.

One approach is to have a dual
stack with both IPv4 and IPv6 configured on the interface of a network device.

Another technique uses an IPv4
tunnel to carry IPv6 traffic. One implementation is IPv6-to-IPv4 (6-to-4)
tunneling. This newer method (defined in RFC 3056, Connection of IPv6
Domains via IPv4 Clouds) replaces an older technique of IPv4-compatible
tunneling (first defined in RFC 2893, Transition Mechanisms for IPv6
Hosts and Routers, which has been made obsolete by RFC 4213, Basic
Transition Mechanisms for IPv6 Hosts and Routers).

Cisco IOS Software Version
12.3(2)T (and later) also allows NAT protocol translation (NAT-PT) between IPv6
and IPv4, providing direct communication between hosts that are using the
different protocol suites.