INTRODUCTION: The Internetoperations, engineering and research communities are putting significantattention into a relatively new Version (actually 15 years old) of the InternetProtocol – IP version 6 (IPv6) designed to solve several architecturallimitations of the existing IPv4 protocol.
The most essential characteristic ofIPv6 is that it has provides orders of magnitude more address space than theworld’s foreseeable IP connectivity needs. IPv6 has become especially pertinentin the last two years because the global Internet address allocationarchitecture relies on the presence of a free pool of IP addresses to allocateto sites operating Internet infrastructure. The Internet Assigned NumbersAuthority (IANA) exhausted its unallocated address pool in February 2011, andthe Asia-Pacific region (represented by the AP-NIC RIR) followed suit in April2011. The remaining RIRs too are expected to run out of unallocated addressesin the next few years. This exogenous pressure from IPv4 address scarcity hasdriven widespread adoption of IPv6 into modern operating systems and networkequipment. Prior to implementation of IPv4, engineers and scientistsworking on ARPANET debated on the length of an IP address.
The debate wasbetween 32-bit and 128-bit address lengths. The resulting scarcity of IPv4 address blocks leads to gradual depletionof IPv4 address space. In order to save and reuse the address blocks, serviceproviders (SP) resort to mechanisms like multiple layers of Network AddressTranslation (NAT). The more ideal approach to solve the issue of addressscarcity facing the networking industry is to move towards the IPv6 addressingscheme. IPv6 provides 3.
4 x 1038 addresses and comeswith other additional improvements. First, it provides increased efficiency inrouting. Second, it provides faster packet processing.
Third, it supportsmulticast thereby overpowering the hassles of broadcasting packets. Fourth, itavoids network address translation (NAT), therefore, proves to be more robust3. IPv6 adoption has been slow and faces numerousobstacles.
First, there is no true financial driver for companies. Theexhaustion of IPv4 address space has been advertised for years and the industryhas developed technology to extend IPv4 address usage. The most popular ofthese technologies is Network Address Translation (NAT). NAT helped to push outthe exhaustion of IPv6 by roughly a decade. This has bought time for IPv6 tomature further.
During this year’s world IPv6 day, the goal is toenable approximately one percent of the Internet with IPv6 support. This is notan estimate of actual IPv6 traffic. The experts expect IPv6 traffic to increaseexponentially in the coming years.
Scope& Assumptions : Thisresearch paper comments on some of the common transition technologies thatwould facilitate the co-existence of both IPv4 and IPv6 addresses in the comingyears. This research paper provides a cable provider-centric approach indescribing the transition technologies. Our research paper only discussesexisting co-existence technologies and tries to determine the advantages anddisadvantages in the transition techniques we’ve researched.
Additionally, ourresearch is focused on those technologies being considered for deployment byour interviewees. Those technologies are Large Scale Network AddressTranslation (LSN), Dual Stack, IPv6 rapid deployment (6rd), Dual Stack Lite(DS-Lite), and NAT64. Our observations and conclusions are based on ourinteractions with the industry experts in IPv6 as well as academic research.
Our research paper follows certain assumptions. Thefirst assumption is that additional IPv4 addresses will not be available in theimmediate future as a result of IPv4 exhaustion. Secondly, that transitioningto IPv6 or implementing IPv4 extension technology are the only solutions thatwill solve the problem of IPv4 address exhaustion.3 IPv6 Adoption Strategies & Technologies NativeDual Stack: TheDual Stack implementation consists of a network topology that provides theability to route and forward IPv4 and IPv6 packets.
This functionality can beat just the customer’s environment, on the SP’s network core, its edges, orsome other combination. The dual stack approach can be deployed across theentire network or in regional areas but in order for the dual stack approach towork, protocol continuity for packets in transit must be met. TranslationTechnologies :Translation technologies translate one protocol intoanother protocol. This facilitates interoperability between the protocols.There are many transitional technologies. In this paper, we focus on NAT64 asmost of the interviewees cited this translation technology the most. FurtherResearch : This research paper offers a broad scope of IPv4/IPv6co-existence technologies ideal for a cable provider network. There arenumerous options for further research.
The scenarios (2, 3 and 7) that were notdiscussed are areas that require further research. In particular further researchon technologies that allow IPv4 hosts to communicate with IPv6 hosts andservices is needed. Additionally, each of the recommended technologies couldalso be further researched by exploring performance and implementation issues. Specificationfor the new version of IP (v6): The newversion of the IP protocol that was to be developed required the following mainobjectives: extend the IP address space, correct the defects of IPv4 standardand improve its performance as much as possible, anticipate future needs, andpromote innovation by simplifying the implementation of functional extensionsto the protocol These objectives were constrained, however, in that they had toretain the principles that made IPv4 such a success”end-to-communication”,”robustness”,and “best effort”. What’snew with IPv6?First ofall, IPv6 provides a much larger address space than IPv4, with the transitionfrom 32-bit coding of IPv4 addresses (4.3 billion addresses) to 128-bit codingof IPv6 addresses (3.4 1038, or 340 billion, billion, billion, billionaddresses).
As a result, IPv6 is seen as an “enabler”, capable ofstretching our imagination. It is also an opportunity to restore the “endto end” communication model, one of the foundations of IPv4 that wasshaken by the massive influx of NATs. In addition, IPv6 provides a new form ofautoconfiguration, known as”stateless” for hosts. For a host, this mechanism consists inautomatically building a local address for it to communicate with itsneighbours, and then to build a global IPv6 address on the basis of theinformation announced by a local router on the network link. The statelessau-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 bettersupport for functionalextensions,by encapsulating them in dedicated optional headers, such as those for securityor mobility. Theintegration of IPv6: how, who and where? Theintegration of IPv6 is a gradual, collective initiative, for which all theplayers in the network are responsible, each according to their own roles andtasks.
There will be no D-day for a sharp ‘switchover’ to IPv6. Before decidinghow this should be carried out, the following questions have to be asked: whatis to be done, by whom, and where? Let us start with what everyone should do ontheir own computer, i.e. upgrade / update the operating system and networkapplications they use, to make them compatible with IPv6. For most operatingsystems and typical network applications, there is almost nothing else to do,since the recent versions handle IPv6 properly.
However, unless you are anadministrator of a large network, in general you will not have to handle all ofthese issues at once. In other words, you can usually take care of yourbusiness and ask the other players later to take charge of theirs, especiallywhen you do not depend on them for yours! Even if you do manage a large networkwith multiple responsibilities, there is no point in doing everything at thesame time, but gradually after a serious task of prioritisation and planning Research Question Theneed of the hour is to enable IPv6 capabilities on all existing networks.However, IPv4 networks cannot upgrade to IPv6 networks immediately.
This ispartially due to the perception of the technical immaturity of IPv6 as comparedto IPv4. Also, service providers are highly risk-adverse and are not receptiveto new changes so instantly. Additionally, there is a lack of IPv6 awareness.The technical incompatibilities to convert all the network understand IPv6 instantly is another issue that must be met.These factors lead us to look for alternatives that support co-existence ofIPv4 and IPv6 addressing schemes in networks 4. The deployment of IPv6 is a phenomenon that has started andis set to grow further in the years to come. There are many issues andobstacles to achieve 100% IPv6 networks directly. Therefore, this paper focuseson the transitional technologies and strategies required to achieve IPv4-IPv6co-existent networks.
EVOLVINGSTRUCTURE OF IPV4 AND IPV6 TOPOLOGIES: Similar to ourbelief that the composition of a maturing IPv6 topology should look more likethe IPv4 topology, we also expect a convergence to occur between the best ASpath between a given pair of in IPv4 and IPv6. An-other reason to compare IPv4and IPv6 AS path congruity is its correlation with performance. In Section 7 weshow that IPv6 data planeperformance is worse than IPv4 when the AS paths differ, butwhen the AS paths are the same, IPv6 performance is comparable to that ofIPv4. Improved congruity betweenIPv4 and IPv6 paths seem to improveIPv6 performance,which is likely to further promote IPv6 deployment. To explore trends incongruity between IPv4and IPv6 paths, wefirst calculate the fraction of AS paths from a given vantage point (VP) towarddual-stacked origin ASes (i.e.
, ASes that advertise both IPv4 and IPv6prefixes) that are identical in IPv4 and IPv6. If there are multiple IPv4 orIPv6 AS paths available between a given VP and an origin AS, we report ithaving an identical AS path if any of the paths are the same. EVOLVINGDYNAMICS OF IPV4 AND IPV6 INFRASTRUCTURE: Continuing toexplore our hypothesis that a maturing IPv6 network should look more like theIPv4 network, we compare the evolution of routing dynamics in IPv4 and IPv6. Inparticular, we focus on the evolution of update churn, correlation between theupdate churn seen from different vantage points, path exploration, andconvergence times in IPv4 and IPv6. We focus on these metrics for the followingreasons. First, we hypothesize that both IPv4 and IPv6 should show a similarrelation between update churn and the size of the underlying topology. Second,due to bussness relationships and dense interconnection among ASes,churnbecomes localized, and each vantage point does not see the same set of routingevents. Consequently, correlation between update churn seen at differentvantage points can serve as a measure of the maturity of the underlying networkand business relationships.
Finally, previous work has shown that end-to-enddelays and loss rates are significantly higher during routing events. It isthus useful to compare the extent of path exploration and routing convergencetimes during routing events. If these metrics are significantly worse in IPv6as compared to IPv4, then it could deter the adoption of IPv6. Features of IPv6IPv6 is a powerfulenhancement to IPv4 with features that better suit current and foreseeablenetwork demands, including the following:· Largeraddress space—IPv6addresses are 128 bits, compared to IPv4’s 32 bits. This larger addressspace provides several benefits, including: improved global reachability andflexibility; the ability to aggregate prefixes that are announced in routingtables; 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 withoutnetwork address translation (NAT); and simplified mechanisms for addressrenumbering and modification.
· Simplifiedheader—Asimpler header provides several advantages over IPv4, including: better routingefficiency for performance and forwarding-rate scalability; no requirement forprocessing checksums; simpler and more efficient extension header mechanisms;and flow labels for per-flow processing with no need to examine the transportlayer information to identify the various traffic flows.· Supportfor mobility and security—Mobilityand security help ensure compliance with mobile IP and IP security (IPsec)standards.Mobility enables people to movearound in networks with mobile network devices, with many having wirelessconnectivity. Mobile IP is an Internet Engineering Task Force (IETF) standardavailable for both IPv4 and IPv6 that enables mobile devices to move withoutbreaks in established network connections. Because IPv4 does not automaticallyprovide this kind of mobility, supporting it requires additionalconfigurations.In IPv6, mobility is built in,which means that any IPv6 node can use it when necessary. The routing headersof IPv6 make mobile IPv6 much more efficient for end nodes than mobile IPv4does.IPsec is the IETF standard for IPnetwork security, available for both IPv4 and IPv6.
Although the functions areessentially identical in both environments, IPSec is mandatory in IPv6. IPSecis enabled and is available for use on every IPv6 node, making the IPv6Internet more secure. IPSec also requires keys for each device, which impliesglobal key deployment and distribution.· Transitionrichness—Thereare a variety of ways to transition IPv4 to IPv6.One approach is to have a dualstack with both IPv4 and IPv6 configured on the interface of a network device.Another technique uses an IPv4tunnel to carry IPv6 traffic. One implementation is IPv6-to-IPv4 (6-to-4)tunneling.
This newer method (defined in RFC 3056, Connection of IPv6Domains via IPv4 Clouds) replaces an older technique of IPv4-compatibletunneling (first defined in RFC 2893, Transition Mechanisms for IPv6Hosts and Routers.The Move TowardIPv6: Issues and ActionsExpertsbelieve that because of the address limitations of the current IPv4 protocol,the Internet is running out of space and we are headed for catastrophe. Thesolution is to deploy IPv6, a next-generation protocol more than three decadesin the making that uses an address bit size four times that of its predecessorand therefore provides a wider range of IP address possibilities.Experts believe that because ofthe address limitations of the current Internet Protocol Version 4 (IPv4), theInternet is running out of address space and we may be headed for an IPcatastrophe. The increasing density of advanced servers, reliance on virtualcomputing, and use of mobile client devices are just a few things acceleratingthe problem, to the point we may run out of IP address options by next year.The solution, the experts say, is to deploy IPv6, a next-generation protocol more thanthree decades in the making that uses an address bit size four times that ofits predecessor and therefore provides a wider range of IP addresspossibilities.