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1.What is IP address
2.When & how it was devised
3.IPV4 Features & its functionality
4.Benefits of IPV4 & Devices supporting IPV4
5.Problems of IPV4 & What happened to IPV5
6.What led to IPV6
7.IPV6 Features & Functionality
8.Benefits of IPV6 & supporting devices
9.How transition from IPV4 to IPV6 will happen
10.Problems & challenges that are anticipated & Conclusion
Refer ----- http://ezinearticles.com/?IPv4-Vs-IPv6-%28A dvantages-and-Disadvantages%29&id=5160096 Rapid Growth of the Internet and the Exhaustion of the IPv4 Addressing IPv4 allows for 4,294,967,296 addresses which is about 4 billion and IP allocation limits the public IP addresses to a few hundred million. Cause of this limitation companies using NAT (Network Address Translator) to map single public IP to multiple private IP addresses. IPv4 Security at IP Level When we communicate at public medium we need to encrypt data to maintain security and privacy. After a passage of time we have now security for IPv4 packets. This security knows as internet protocol security or IPSec but this is an optional for IPv4. Internet Backbone Maintaining Large Routing Tables In IPv4 network IDs allocation is very critical and currently more than 87000 routes in the routing tables of internet backbone routers today. The routing infrastructure is based on flat and hierarchical routing. Quality of Service Concern in IPv4 Now a days internet users are not only limited with browsing and searching data. Current users are well aware of text and voice and video chat and video conferences and online video libraries. This kind of communication need real time data transfer for quality of service. Normally for these kind of services we use UDP (User Data-gram Protocol) or TCP (Transmission Control Protocol).IPv4 TOS field has limited functionality and, over time, has been redefined and locally interpreted. Additionally, payload identification that uses a TCP or UDP port is not possible when the IPv4 packet payload is encrypted. IPv6 As we can see we have some basic problems in practice of IPv4 now we will check some new features of IPv6. here I like to describe the some of basic features of IPv6. Deployment of IPv6 is a big challenge for internet management groups, stake holders and service providers. It is difficult but not impossible. We can see benefits of IPv6 here. Biggest upgrade jump from IPv4 32 bit to IPv6 128 bit. IPv6 Header Format New header is designed to minimize header overhead. by moving both nonessential and optional fields to extension headers that are placed after the IPv6 header. IPv6 header is more efficiently processed at intermediate routers and that generates efficiency. IPv6 is 4 time larger than IPv4 and its header size is twice than older version. IPv6 Large Addressing Space In IPv6 source and destination addresses is based on 128 bit. 128 bit addressing can produce over 3.4 x 1038 possible combinations. Currently we can say this is enough but who know about future may be it also face same problem like IPv4 after some decades. 128 bit addressing allow us multiple levels of sub-netting and address allocation. So we can say that we have plenty of address for use in future. Addressing and Routing Infrastructure Efficiency in IPv6 IPv6 designed to create an efficient, hierarchical, and summarize able routing infrastructure that is based on the common occurrence of multiple levels of Internet Service Providers. It reduce the size of routing table of backbone routers. Which is can cause of efficient internet experience. Security features is now built-in IPv6 has been design to support IPsec (AH and ESP header support required) also support mobility version Mobile IPv6. IPSec based on two types of extension headers and a protocol to negotiate security settings. The Authentication header (AH) provides data integrity, data authentication, and replay protection for the entire IPv6 packet. It is better form developers who built-in security features in development of IPv6 rather we bolt on later. Quality of Service (QoS) of IPv6 As we have already seen about the UDP and TCP protocols for streaming and other multimedia services on internet. Cause the usage of these services are increasing day by day IPv6 have a flow level field in its header which make better and special handling for packets from source to destination. Data traffic is identified in the IPv6 header, support for QoS can be achieved even when the packet payload is encrypted with IPSec and ESP. Article Source: http://EzineArticles.com/5160096 ========== We can see the rapid growth of internet users in last few years and this increase also create challenges for internet management groups, stake holders and service providers. Day by day infrastructure of internet is expanding and we can even enjoy the service of internet in villages and remote areas. Increased of usage also increase online devices. In start internet protocol addressing (a specific IP addressing for each online entity) was designed on 32 bit and this scheme IP version called IPv4.IPv4 addressing is like 203.128.076.001. decimal is used to make the IPv4 addresses more palatable for humans and a 32-bit address becomes 4 decimal numbers separated by the period (.) character. If we calculate these decimal values and we can get the total number of devices can be participate on this protocol (256x256x256x256) = allows for 4,294,967,296 addresses. It is about 4 billion of addresses and in early days of internet no one can think, 4 billion slot will be full. here we shall discus some disadvantages of IPv4 as we have seen addressing capability problem and after that we shall go through the solution which will replace IPv4 and addressing structure of the new addressing scheme. we shall go through some disadvantages of IPv4 and new features of IPv6.
What happened to IPv5? Version 5 of the IP family was an experimental protocol developed in the 1980s. IPv5(also called the Internet Stream Protocol) was never widely deployed. Since the number 5 was already allocated, this number was not considered for the successor to IPv4. Several proposals were suggested as the IPv4 successor, and each was assigned a number. In the end,it happened that the one with the version number 6 was swlected. • Version 5 of the IP family was an experimental protocol developed in the 1980s. IPv5 (also called the Internet Stream Protocol) was never widely deployed. Since the number 5 was already allocated, this number was not considered for the successor to IPv4. Several proposals were suggested as the IPv4 successor, and each was assigned a number. In the end, it happened that the one with version number 6 was selected.
Benefits of 128 bit Addresses Room for many levels of structured hierarchy and routing aggregation • Easier address management and delegation thanIPv4 • Easy address auto-configuration • Ability to deploy end-to-end IPsec (NATs removed as unnecessary) http://happyrouter.com/ipv6-limitations-vs-ipv4 IPv6 is one of the useful delivery protocols for the future fixed and wireless/mobile network environments. The necessity of IPv6 protocol will be more and more increasing for the NGN.
The IPv6 story began in the early nineties when it was discovered that the address space available in IPv4 was vanishing quite rapidly. Contemporary studies indicated that it may be depleted within the next ten years – around 2005! These findings challenged the Internet community to start looking for a solution. Two possible approaches were at hand: 1. Minimal: Keep the protocol intact, just increase the address length. This was the easier way promising less pain in the deployment phase. 2. Maximal: Develop an entirely new version of the protocol. Taking this approach would enable incorporating new features and enhancements in IP. Because there was no urgent need for a quick solution, the development of a new protocol was chosen. Its original name IP Next Generation (IPng) was soon replaced by IP version 6 which is now the definitive name. The main architects of this new protocol were Steven Deering and Robert Hinden.
IPv6 is one of the useful delivery protocols for the future fixed and wireless/mobile network environments. The necessity of IPv6 protocol will be more and more increasing for the NGN. Benefits of 128 bit Addresses Room for many levels of structured hierarchy and routing aggregation • Easier address management and delegation thanIPv4 • Easy address auto-configuration • Ability to deploy end-to-end IPsec (NATs removed as unnecessary) IPv6 is one of the useful delivery protocols for the future fixed and wireless/mobile network environments. The necessity of IPv6 protocol will be more and more increasing for the NGN.
Three strategies have been devised by the IETF(Internet Engineering Task Force)
A dual-stack node has complete support for both protocol versions. In communication with an IPv6 node, such a node behaves like an IPv6-only node; in communication with an IPv4 node, it behaves like an IPv4-only node. Implementations may have a configuration switch to enable or disable one of the stacks, so this node type can have three modes of operation. When the IPv4 stack is enabled and the IPv6 stack is disabled, the node behaves like an IPv4-only node. When the IPv6 stack is enabled and the IPv4 stack disabled, it behaves like an IPv6-only node. When both the IPv4 and IPv6 stacks are enabled, the node can use both protocols. An IPv6/IPv4 node has at least one address for each protocol version. It uses IPv4 mechanisms to be configured for an IPv4 address (static configuration or DHCP) and uses IPv6 mechanisms to be configured for an IPv6 address (static configuration or autoconfiguration). DNS is used with both protocol versions to resolve names and IP addresses. An IPv6/IPv4 node needs a DNS resolver that is capable of resolving both types of DNS address records. The DNS A record resolves IPv4 addresses, and the DNS AAAA (referred to as quad-A) record resolves IPv6 addresses.
Dual stack approach with DNS How a client application does decide if it should use IPv4 or IPv6 protocol stack to communicate to server? It simply can be hardcoded within the application or can rely on DNS reply. For example, when a client want to establish a connection to server named “test.com”, it will send a DNS query to DNS server to resolve “test.com”. If the test.com server is IPv4 based, a A record will be replied back to querier with some IPv4 address. Client on receiving it will use IPv4 protocol stack for further activities. If test.com server is IPv6 based, AAAA record or a quad-A record will be replied back to querier with IPv6 address.
IPv6 tunneling is the way of transporting IPv6 packets over IPv4 infrastructure by encapsulating IPv6 packet with IPv4 header. Tunnel establishment can either be manual or automatic. Semi automated tunnels can also be established using Tunnel broker approach. As part of migration, situation may also arise where IPv4 packets may need to be encapsulated over IPv6 infrastructure.
Manual 6to4 Tunnel : This is a simple point-to-point tunnel that needs to be statically configured between two end points which are dual stacked by running IPv4 facing the core and IPv6 facing the CE side. IPv6 packet will be encapsulated with IPv4 header on ingress side with IP protocol number = 41 and no additional header.
6RD prefix is a variable length prefix that can be of Service Providers choice from the prefix they received from registry. Embedded IPv4 address is a variable length field where normally the IPv4 address of the remote side CE or BR will be embedded. Subnet ID is another variable length field. ALL 6RD CE and 6RD BR will be given with same 6RD prefix to which it will append/embed its own IPv4 address (after compression if required). Interface ID is 64 bit field which will be derived from host MAC address.
NAT-PT (Network Address Translation – Protocol Translation) : Statically or dynamically configure a translation of a IPv4 network address into an IPv6 network address and vice versa. NAT-PT also ties in an Application Layer Gateway (ALG) functionality that converts Domain Name System (DNS) mappings between protocols. NAT64 – Network Address Translation 6to4 : NAT64 is said to replacing NAT-PT and is currently recommended for deployment.
What is IP? The Internet Protocol (IP) is the method or protocol by which data is sent from one computer to anotherNumber / Address on the Internet. Eg:- 172.27.176. 126 Internet History Protocol In 1978, the Office of the Secretary of Defence (OSD) mandated the use of IPv4 for all “host-to-host” dataNumber / Address exchange enabling IPv4 to become the mechanism for the military to create integrated versus stove piped communications.
3 ways a machine can be identified in N/W System Name (Needs to be unique in Network) firstname.lastname@example.org MAC Address Also called as Physical Address Defined by Manufacturer
IP Address-Logical Address Generally of 2 types IPv4 & IPv6
Source IP Address Destination IP Address Protocol (Whether to pass up to TCP or UDP) Checksum (Verify that the packet arrives intact) Time to Live(TTL) (Designates the number of second the datagram is allowed to stay in the network before it is discarded -- NT defaults at 128 Seconds
* IP Version 1 - 3 were not formally assigned* IP Version 4 - TCP/IP -- 32 bit IP address, currently used* IP Version 5 -- Streamed Protocol(ST), a connection-oriented internet-level protocol* IP Version 6 -- Designed to Replace IPv4 - 128 bit IP address.
* Connectionless Protocol & Best effort based* Create virtual layer over diversified Devices* Simplicity It is simpler , easy to remember Require less memory* Familiarity Millions are devices are already knowing it Existing infrastructure already support it
* Classful addressing* Classless addressing* Special Address* NATing
* Millions of class A addresses are wasted.* Many class B addresses are wasted.* Not so many organizations are so small to have a class C block.* The only block of class E addresses was reserved for future purposes.* The range of addresses allocated to an organization in classful addressing was a block of addresses in Class A, B, or C.
* Subnetting and supernetting in classful addressing did not really solve the address depletion problem. With the growth of the Internet, it was clear that a larger address space was needed as a long-term solution. Although the long-range solution has already been devised and is called IPv6, a short- term solution was also devised to use the same address space but to change the distribution of addresses to provide a fair share to each organization. The short-term solution still uses IPv4 addresses, but it is called classless
* Widely supported* Shorter the sweeter (header)* Support of All OS* All Commonly used protocols are supported
* PCs* Server* Modem* Routers* Cameras* Printers* Smartphones,* Tablets, Gaming systems and just about everything else connecting to the Internet
* IPv4 Has Been in Use Since 1978 - No substantial updates/improvement* Exhaustion of IPv4 Address Space - Explosive growth of the commercial internet - Increase of IP-enabled devices* Integrated Security - Originally IPv4 specification did not identify any security mechanism - IPsec was a later addition for IP* Scalability - Internet backbone routers maintaining large Routing Tables - Quality of Service Concern
* Version 5 of the IP family was an Experimental Protocol developed in the 1980s* Internet Stream Protocol* Never introduced for public use* Number 5 was already allocated, this number was not considered for the successor to IPv4
Source: Geoff Huston*About 10,000 new entries per year*In theory, less instability at the edges (why?)
T. Hain, “A Pragmatic Report on IPv4 Address Space Consumption”, Cisco IPJ, September 2005Claim: remaining /8s will be exhausted within the next 5-10 years.
* IPv6 provides a platform for new Internet functionality that will be needed in the immediate future, and provide flexibility for further growth and expansion.* Benefits of IPv6* New header format* Large address space* Efficient and hierarchical addressing and routing infrastructure* Stateless and state-full address configuration* Built-in security* Better support for quality of service (QoS)* New protocol for neighboring node interaction* Extensibility
The recommended proposal was SIPP with 126 bit address size.IPv6 Introduction 25
New header format Large address space Efficientand hierarchical addressing and routing infrastructure Stateless and state-full address configuration Built-in security Better support for quality of service (QoS) New protocol for neighboring node interaction Extensibility
Feature IPv4 IPv6 Networks must be configured manually or with IPv6 networks provide autoconfigurationEasier management of DHCP. IPv4 has had many overlays to handle capabilities. They are simpler, flatter and more networks Internet growth, which demand increasing manageable, especially for large installations. maintenance efforts. Widespread use of NAT devices means that a Direct addressing is possible due to vast addressEnd-to-end connective single NAT address can mask thousands of space - the need for network address translation integrity non-routable addresses, making end-to-end devices is effectively eliminated. integrity unachievable. 4.29 x 109 = 4.2 billion addresses - far less 3.4 x 1038 = 340 trillion trillion trillion addresses -Unconstrained address than even a single IP address per person on about 670 quadrillion addresses per square abundance the planet. millimetre of the Earths surface. IPv4 was designed as a transport and Given the numbers of addresses, scalability andPlatform for innovation communications medium, and increasingly any flexibility of IPv6, its potential for triggering and collaboration work on IPv4 is to find ways around the innovation and assisting collaboration is constraints. unbounded. Integrated Relatively constrained network topologies IPv6 provides interoperability and mobility interoperability and restrict mobility and interoperability capabilities capabilities which are already widely embedded mobility in the IPv4 Internet. in network devices. Improved security Security is dependent on applications - IPv4 IPSEC is built into the IPv6 protocol, usable with features was not designed with security in mind. a suitable key infrastructure.
IP Next Generation Protocol IPv6New header format More attractive for future Internet applications compared to IPv4Potential socio-economic benefits for Multi Access:ubiquity of the Internet ; Enhanced life mobility
The basic IPv4 packet header has 12 fields with a total size of 20 octets (160 bits).The basic IPv6 packet header has 8 fields with a total size of 40 octets (320 bits).
Large address space –32 bit vs. 128 bit Although only a small percentage of possible addresses are currently allocated for use by hosts, there are plenty of addresses available for future use. With a much larger number of available addresses, address- conservation techniques, such as the deployment of NAT server’s, are no longer necessary. Efficient and hierarchical addressing and routing infrastructure IPv6 global addresses used on the IPv6 portion of the Internet are designed to create an efficient, hierarchical, & summarizable routing infrastructure that addresses the common occurrence of multiple levels of Internet service providers. On the IPv6 Internet, backbone routers have much smaller routing tables. Stateless and stateful address configuration To simplify host 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 (link-local addresses) and with addresses that are 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. Built-in 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.
Better support for quality of service (QoS) New fields in the IPv6 header define how traffic is handled and identified. Traffic identification, by using a Flow Label field in the IPv6 header, allows routers to identify and provide special handling for packets that belong to a flow. A flow is a series of packets between a source and destination. Because the traffic is identified in the IPv6 header, support for QoS can be easily achieved even when the packet payload is encrypted with IPSec. 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 (that is, nodes on the same link). Neighbor Discovery replaces Address Resolution Protocol (ARP), ICMPv4 Router Discovery, and ICMPv4 Redirect messages with efficient multicast and unicast messages and provides additional functionality. Extensibility IPv6 can be extended for new features by adding extension headers after the IPv6 header. Unlike 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. • Other features inherent to IPv6 Security encryption Header Encryption Sender Authentication Privacy
* IPv6 addresses are 128 bits long, compared to 32 bits for IPv4 addresses. IPv6 addresses are represented as 8 chunks of 16 bits in hexadecimal separated by colons, compared to 4 chunks of 8 bits in decimal (dotted- quad) for IPv4. For example, IPv4 addresses looks like:* 188.8.131.52 184.108.40.206 220.127.116.11* whereas IPv6 addresses looks like:* 2620:0:e50:2::1 2001:4860:800b::67 2001:550:1::cc01* In IPv6, leading 0s in each chunk can be omitted, & a single instance of consecutive 0s can be replaced with "::". For example, the following IPv6 addresses are equivalent:* 2620:0000:0e50:0002:0000:0000:0000:0001 2620:0:e50:2:0:0:0:1 2620:0:e50:2::1* Finally, IPv6 addresses use the same prefix/length notation which is now used for IPv4 to specify blocks of address space. The "prefix" is the base address of the block. The "length" is the number of bits from the left which are the same for all addresses in the block. This is often called "CIDR notation" because it was created when Classless Inter-Domain Routing was employed in the IPv4 Internet. For example:
Without rich support from our common hardware vendors IPv6 deployment will never become a reality. While core network equipment and Operating Systems are finally showing mature IPv6 implementations what good does that do us if our Printers, LAN switches, Battery Backup Systems, etc. dont support IPv6. All hardware and vendors which need to be IPv6 capable should to be listed on this page so that if their implementations are lacking, market pressure can be put forth by the customers of their product.
IPv6 Features and BenefitsThe evolution of the IPv6 protocol represents years of effort by many different InternetEngineering Task Force (IETF) working groups. IPv6 was designed to build on theexisting features of IPv4 and remedy many of its limitations by doing the following: • Extend the address space for end-to-end global addressability and Internet scalability—enough to offer a globally unique IP address to any device in the foreseeable future. • Simplify IPv6 data packet header for extensibility and performance. • Enable stateless IP auto-configuration, easier network renumbering, and improved plug and play support. • Provide support for network address renumbering. • Enable prefix delegation of IPv6 addresses to support renumbering and auto- configuration. • Enable mandatory implementation of IP Security (IPsec) support for all fully • Leverage the improved support for IP mobility inherent in IPv6. in IPv4). IPv6-compliant devices (IPsec implementation is not mandatedListed below is an overview of several features and benefits IPv6 is intended to provide. • Larger address space - IPv6 increases the IP address size from 32 bits to 128 bits, thereby increasing the number of globally routable IP addresses from approximately 4,300,000,000 (4.3×109) to 340,282,366,920,938,463,463,374,607,431,768,211,456 (3.4×1038). Theoretically, IPv6 could provide an IPv6 /48 address prefix block (1,208,925,819,614,629,174,706,176 IP addresses) for every 10 square meters on earth. Increasing the address space to 128 bits provides the following additional potential benefits: o Enhanced applications functionality - Enables peer-to-peer, infrastructure-less applications and networking (vs. client-server model). o End-to-end transparency - Reduces motivations for address translation technologies. o Hierarchical addressing - Summarizes and manages routing table growth. o Auto-configuration - The unicast IPv6 addressing architecture uses one half of the address (64 bits) to embed IEEE extended unique identifiers (EUI-64) in each interface address. The use of globally unique EUI-64s on o each interfaceof multicast routing - IPv6 provides a much larger pool of Scalability allows systems to derive globally unique IPv6 addresses automatically from simple announcements from neighboring systems. multicast addresses with multiple scoping options.
• Auto-configuration - Clients using IPv4 addresses use the Dynamic Host Configuration Protocol (DHCP) server every time they log onto a network. This process is called ‘stateful auto-configuration.’ IPv6 supports a revised DHCPv6 protocol to support similar stateful auto-configuration, but also supports stateless auto-configuration of nodes that do not require a server to obtain addresses, but uses router advertisements to create an address. This creates a “plug-and-play” environment and can simplify management and administration. IPv6 also allows automatic address configuration and reconfiguration, empowering administrators 2.0 Components of addresses without accessingPlan to renumber network an IPv6 Transition all clients.The following section provides agencies with a list of components that could be used asthe basis for an IPv6 transition plan. Although agencies are not required to include all ofthese components in their transition plans, it is recommended that agencies cross-checktheir own plans against this list to ensure that no critical transition elements have beenoverlooked. 1. Strategic business objectives. 2. Transition priorities and milestones. 3. Creation of transition criteria for legacy, upgraded, and new capabilities. 4. Means for adjudicating claims that an asset should not transition in prescribed timeframes. 5. Technical strategy and selection of transition mechanisms to support IPv4/IPv6 interoperability. 6. Management and assignment of resources for transition. 7. Maintenance of interoperability and security during transition. 8. Use of IPv6 standards and products. 9. Support for IPv4 infrastructure during and after 2008 IPv6 network backbone deployment. 10. Application migration (if required to support backbone transition). 11. Costs not covered by technology refresh. 12. Transition governance: a. Policy b. Roles and responsibilities c. Management structure d. Performance measurement e. Reporting. 13. Acquisition and procurement. 14. Training. Page 4 of 18
IPv6 Terminology• Node - A device that implements IPv6. - A node can be a host or a router - A node can be an entertainment system - A node can be a PDA or cell phone
IPv6 Terminology• Router - A node that forwards IPv6 packetsnot explicitly addressed to itself. - Routers operate at the Network Layer - Routers use metrics to determine optimal paths which network traffic should be forwarded
IPv6 Terminology• Host - Any node that is not a router - A host can be your computer at home - A host can be your cell phone or PDA
IPv6 Terminology• Upper Layer - A protocol layerimmediately above IPv6. - TCP/UDP - ICMP - OSPF - And many more…
IPv6 Terminology• Link - A communication facility or mediumover which nodes can communicate at the Data Link Layer. ethernet - Ethernet MTU 1500 - Token ring - Frame relay - A “tunnel” Token-ring MTU 4464 - And many more…
IPv6 Terminology• Neighbors - Nodes attached to the samelink. - 2 PC’s on a hub can be neighbors - Hosts and routers can be neighbors ethernet MTU 1500 Host A Host B
IPv6 Terminology• Interface - A node’s attachment to a link. - A Network Interface Card (NIC) is an interface - A node can have more than one interface - Routers often have multiple interfaces - A PC’s dial-up adapter is an interface
IPv6 Terminology• Address - An IPv6-layer identifier for aninterface or a set of interfaces. - 128-bit address - Prefix represented by /nn bits - New address structure (to be discussed)3ffe:80f0:ffff:1::202/64
IPv6 Terminology• Packet - An IPv6 header plus payload. - Cannot be larger than the “Path MTU”* - Includes header and header extensions - Delivered in frames
IPv6 Terminology• Link MTU - The maximum transmission unit, or packet size, given in octets, that can be conveyed in one piece over a link. - MTU - Maximum Transmission Unit - Ethernet MTU is 1500 octets - 4mb Token Ring MTU is 4464 octets ethernet Token-ring MTU 1500 MTU 4464
IPv6 Terminology• Path MTU - The minimum link MTU of allthe links in a path between a source nodeand a destination node. - The smallest MTU in a network path ethernet MTU 1500 ethernet MTU 1500 Host A router router MTU 1400 Host B
Huge number of systems on the Internet, the transition from IPv4to IPv6 cannot happen suddenly.It will take a considerable amount of time before every system inthe Internet can move from IPv4 to IPv6.The transition must be smooth to prevent any problems betweenIPv4 and IPv6 systems.
Three strategies have been given by the IETF(Internet Engineering Task Force)
•A dual-stack node has complete support for both protocol versions.•DNS is used with both protocol versions to resolve names and IP addresses.
• Tunneling basically provides a way to use an existing network layer infrastructure to carry a different network layer protocol. For example, IPX over IPv4 network, IPv6 over IPv4 network.•Tunneling - Transporting IPv6 traffic through an IPv4 network transparently.• On a broader view tunneling technique can be classified as, 2. 1 IPv6 tunnel over IPv4 infrastructure 2. 2 Pv4 tunnel over IPv6 infrastructure IPv4 header IPv6 header Payload
2.1 IPv6 tunnel over IPv4 infrastructureBelow are few of the tunneling technique to connect IPv6 network over IPv4 cloud.•Manual 6to4 Tunnel - A manually created IPv6 tunnel is configured between two routers that each must support both IPv4 and IPv6.•IPv6 over GRE Tunnel - Generic Routing Encapsulation protocol is one tunneling protocol that encapsulates one network layer protocol into other that develop by CISCO•Automatic 6to4 Tunnel - automatically set up using the 2002::/16 IPv6 address space. •ISATAP - ISATAP (Intra-Site Automatic Tunnel Addressing Protocol) is another mechanism to transport IPv6 traffic over IPv4 infrastructure.
IPv6 Rapid Deployment (6RD) Technique:•6RD (IPv6 Rapid Deployment) is the latest tunneling technique used to transport IPv6 traffic over IPv4 SP network. •This is an extension of automatic 6to4 tunneling mechanism with key differentiator that it utilizes SP’s own prefix instead of reserved prefix like 2002::/16. •6RD domain consists of 2 components as 6RD CE and 6RD BR (Border Router).
Translation – Converting IPv6 traffic to IPv4 traffic for transport and vice versa.Translation method provides a way to translate IPv6 to IPv4 traffic and vice versa. When using translation, the traffic is not encapsulated but is converted to the destination type (be that IPv4 or IPv6). There are two methods that are typically used with translated IPv6 networks; these include:•NAT-PT (Network Address Translation – Protocol Translation)•NAT64 – Network Address Translation 6to4
Considering the fact being that the whole Internet is currently running on IPv4 network, it is not an easy task to migrate network from IPv4 to IPv6. Below are few challenges currently we face as part of migration,•Hardware and Software Compatibility : You must ensure that your existing equipment, especially core communication equipment that must be able to support IPv6.•IPv6 Address Length and Volume : IPv6 is in hexadecimal and incredibly large, which translates to not user friendly.•IPv6 Address Interface : Administrators must understand this change in case multiple addresses are ever required on an interface.•While Service provider’s current customer base is running on IPv4 network, any new customer may be based on IPv6. This requires that SP core should handle both IPv4 and IPv6 customers without compromising with performance.• While any new business applications will be developed based on IPv6, current applications are IPv4 based. This requires that at least for few years, IPv4 and IPv6 network should co-exist and inter communicate.
• Clearly, the acceleration of IPv4 address exhaustion leaves service providers no choice but to prepare for the transition to IPv6.• Comprehensive migration plan for your network can be a daunting task.• Migrating to IPv6 involves the upgrading of applications, hosts, routers, and DNS to support IPv6.• Because the migration might take years, IPv6/IPv4 nodes must be able to coexist over IPv4 infrastructures such as the Internet and private intranets.