IPv6 is short for 'Internet Protocol Version 6'. IPv6 is the 'next generation' protocol designed by the IETF to replace the current version Internet Protocol, IP Version 4 ('IPv4').

Most of today's internet uses IPv4, which is now nearly twenty years old. IPv4 has been remarkably resilient in spite of its age, but it is beginning to have problems. Most importantly, there is a growing shortage of IPv4 addresses, which are needed by all new machines added to the Internet.

IPv6 fixes a number of problems in IPv4, such as the limited number of available IPv4 addresses. It also adds many improvements to IPv4 in areas such as routing and network autoconfiguration. IPv6 is expected to gradually replace IPv4, with the two coexisting for a number of years during a transition period.

The main feature of IPv6 that is driving adoption today is the larger address space: addresses in IPv6 are 128 bits long versus 32 bits in IPv4.

The larger address space avoids the potential exhaustion of the IPv4 address space without the need for NAT and other devices that break the end-to-end nature of Internet traffic. The drawback of the large address size is that IPv6 is less efficient in bandwidth usage, and this may hurt regions where bandwidth is limited.

Presented by:
Minal Mishra

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IP Network Addressing
 INTERNET à world’s largest public data network, doubling in size every nine months
 IPv4, defines a 32-bit address - 232 (4,294,967,296) IPv4 addresses available
 The first problem is concerned with the eventual depletion of the IP address space.
 Traditional model of classful addressing does not allow the address space to be used to its maximum potential.
 Classful Addressing
 When IP was first standardized in Sep 1981, each system attached to the IP based Internet had to be assigned a unique 32-bit address
 The 32-bit IP addressing scheme involves a two level addressing hierarchy
Classful Addressing…
 Divided into 5 classes
 Class A 8 bits N/W id and 24 bits host id and so on B,C.
 Wastage of IP addresses by assigning blocks of addresses which fall along octet boundaries
 Techniques to reduce address shortage in IPv4
 Subnetting
 Classless Inter Domain Routing (CIDR)
 Network Address Translation (NAT)
Subnetting
 Three-level hierarchy: network, subnet, and host.
 The extended-network-prefix is composed of the classful network-prefix and the subnet-number
 The extended-network-prefix has traditionally been identified by the subnet mask
Subnetting Example
Classless Inter-Domain Routing
 Eliminates traditional classful IP routing.
 Supports the deployment of arbitrarily sized networks
 Routing information is advertised with a bit mask/prefix lengthà specifies the number of leftmost contiguous bits in the network portion of each routing table entry
 Example: 192.168.0.0/21
CIDR Table Entry…
 Extract the destination IP address.
 Boolean AND the IP address with the subnet mask for each entry in the routing table.
 The answer you get after ANDing is checked with the base address entry corresponding to the subnet mask entry with which the destination entry was Boolean ANDed.
 If a match is obtained the packet is forwarded to the router with the corresponding base address
Network Address Translation
 Each organization- single IP address
 Within organization – each host with IP unique to the orgn., from reserved set of IP addresses
NAT Example
Features of IPv6
 Larger Address Space
 Aggregation-based address hierarchy
– Efficient backbone routing
 Efficient and Extensible IP datagram
 Stateless Address Autoconfiguration
 Security (IPsec mandatory)
 Mobility
Major Improvements of IPv6 Header
 No option field: Replaced by extension header. Result in a fixed length, 40-byte IP header.
 No header checksum: Result in fast processing.
 No fragmentation at intermediate nodes: Result in fast IP forwarding.
Extension Headers
 Routing – Extended routing, like IPv4 loose list of routers to visit
 Fragmentation – Fragmentation and reassembly
 Authentication – Integrity and authentication, security
 Encapsulation – Confidentiality
 Hop-by-Hop Option – Special options that require hop-by-hop processing
 Destination Options – Optional information to be examined by the destination node
Stateless Address Autoconfiguration
 3 ways to configure network interfaces: Manually, Stateful, Stateless
 IPSAAà IPv6 addr. Separated into 2 2 parts: network and interface id.
 Link- local addresses: prefix FE80::0 + interface identifier (EUI-64 format)
 Obtain network id through Router solicitation (RS)
Conclusion
 IPv6 is NEW …
– built on the experiences learned from IPv4
– new features
– large address space
– new efficient header
– autoconfiguration
 … and OLD
– still IP
– build on a solid base
– started in 1995, a lot of implementations and tests done

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1. INTRODUCTION
Internet Protocol (IP) is the “language” and set of rules computers use to talk to each other over the Internet. The existing protocol supporting the Internet today - Internet Protocol Version 4 (IPv4) - provides the world with only 4 billion IP addresses, inherently limiting the number of devices that can be given a unique, globally routable address on the Internet. The emergence of IPv6, providing the world with an exponentially larger number of available IP addresses, is essential to the continued growth of the Internet and development of new applications leveraging mobile Internet connectivity. Although the information technology (IT) community has come up with workarounds for this shortage in the IPv4 environment, IPv6 is the true long-term solution to this problem.
Federal government agencies should prepare for the future of networking and Internet technology by enabling their networks to support IPv6 addresses and data packets. There are many considerations when introducing any emerging technology into an organization’s infrastructure. Therefore, this type of transition should be done methodically and mindfully, with full awareness of the benefits, challenges, and caveats surrounding the technical implementation of IPv6. This document outlines many of these benefits, challenges, and caveats, and provides Federal government agencies with IPv6 transition “best practices” which can be used to inform agency IPv6 transition planning and the adoption of IPv6 into their IT infrastructure.
2. HISTORY OF IPV6
In August of 2005, the Office of Management Budget issued Memorandum M-05-22, “Transition Planning for Internet Protocol Version 6 (IPv6)”, establishing the goal of enabling all Federal government agency network backbones to support the next generation of the Internet Protocol Version 6 (IPv6) by June 30, 2008.
The memorandum requires the agency’s network backbone to be ready to transmit both IPv4 and IPv6 traffic, and support IPv4 and IPv6 addresses, by June 30, 2008. Agencies must be able to demonstrate they can perform at least the following functions, without compromising IPv4 capability or network security:
• Transmit IPv6 traffic from the Internet and external peers, through the network backbone (core), to the LAN.
• Transmit IPv6 traffic from the LAN, through the network backbone (core), out to the Internet and external peers.
• Transmit IPv6 traffic from the LAN, through the network backbone (core), to another LAN (or another node on the same LAN).
The requirements for June 30, 2008 are for the network backbone (core) only. IPv6 does not actually have to be operationally enabled (i.e. turned on) by June 30, 2008. However, network backbones must be ready to pass IPv6 traffic and support IPv6 addresses. Applications, peripherals, and other IT assets which are not leveraged in the execution of the functions mentioned above are not required for the June 30, 2008 deadline. Agencies are expected to verify this new capability through testing activities. They are also required to maintain security during and after adoption of IPv6.
In support of these goals, OMB Memorandum 05-22 identifies several key milestones and requirements for all Federal government agencies. These requirements are:
- By November 15, 2005
• Identify an IPv6 agency lead
• Complete inventory of IP-aware hardware devices in network backbone
- By February 28, 2006
• Develop a network backbone transition plan for IPv6
• Complete an IPv6 progress report
- By June 30, 2006
• Complete inventory of IP-aware applications and peripherals with dependencies on network backbone
• Complete an IPv6 transition impact analysis
- By June 30, 2008
• Complete network backbone transition to IPv6
3. IPV6 OVERVIEW
IPv6 is the next generation protocol for the Internet, designed to support continued Internet growth in number of users and functionality. The current version, IPv4, was developed in the 1970’s and provides the basis for today’s Internet interoperability. IPv4 suffers some limitations that may be inhibitors to growth of the Internet, and use of the Internet as a global networking solution. IPv4 allows for as many as 232 (4,294,967,296) addresses. Although this seems like a very large number, it is much too small for tomorrow’s Internet. Considering the population of the Earth is approximately 6.6 billion people, with IPv4 we can not even afford to give a single IP address to every person on the Earth.
IPv6 has been under development by the Internet community for over ten years and is designed to overcome these limitations by greatly expanding available IP address space, and by incorporating features such as end-to-end security, mobile communications, quality of service, and system management burden reduction. The true transition of the global Internet from IPv4 to IPv6 is expected to span many years. During this period of transition, many organizations introducing IPv6 into their infrastructure will operate in a dual-stack environment supporting IPv4 and IPv6 concurrently, possibly for the foreseeable future. There is not a one-size fits all transition strategy for IPv6. The incremental, phased approach allows for a significant period where IPv4 and IPv6 can co-exist using one or more transition mechanisms to ensure interoperability between the two protocol suites.
4. IPV6 FEATURES AND BENEFITS
The evolution of the IPv6 protocol represents the work of many different Internet Engineering Task Force (IETF) proposals and working groups, and represents several years of effort. IPv6 was designed to build on the existing features of IPv4 and provide new services and capabilities. The rationale is to:
• Extend the IP address space enough to offer a unique IP address to any device.
• Enable stateless IP auto-configuration and improved “plug and play” support
• Provide support for network address renumbering.
• Enable mandatory implementation of IP Security (IPsec) support for all fully IPv6-compliant.
• Improve support for IP Mobility.
Listed 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. Increasing the size of the address field increases number of unique 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). Increasing the address space to 128 bits provides the following additional potential benefits:
o Enhanced applications functionality –Simplifies direct peer-to-peer applications and networking by providing a unique address to each device.
o End-to-end transparency – The increased number of available addresses reduce the need to use address translation technologies
o Hierarchical addressing – The hierarchical addressing scheme provides for address summarization and aggregation. These approaches simplify routing and manage routing table growth.
o Auto-configuration – Clients using IPv4 addresses use the Dynamic Host Configuration Protocol (DHCP) server to establish an address each time they log into a network. This address assignment process is called stateful auto-configuration. IPv6 supports a revised DHCPv6 protocol that supports stateful auto-configuration, and supports stateless auto-configuration of nodes. Stateless auto-configuration does not require a DHCP server to obtain addresses. Stateless auto-configuration uses router advertisements to create a unique address. This creates a “plug-and-play” environment, simplifying address management and administration. IPv6 also allows automatic address configuration and reconfiguration. This capability allows administrators to re-number network addresses without accessing all clients.
o Scalability of multicast routing – IPv6 provides a much larger pool of multicast addresses with multiple scoping options.
5. IPV6 HEADER FORMAT AND ADDRESSING
The IPv6 header has been streamlined for efficiency (Figure 2). The new format introduces the concept of an extension header, allowing greater flexibility to support optional features. Fields in the IPv6 header are:
• Version: 4-bit Internet Protocol version number, value = 6.
• Traffic Class: 8-bit traffic class field, similar to type of service in IPv4.
• Flow Label: 20-bit flow label, used to identify traffic flow for additional control on quality of service.
• Payload Length: 16-bit unsigned integer, length of the IPv6 payload.
• Next Header: 8-bit selector, used to identify the type of header immediately following the IPv6 header.
• Hop Limit: 8-bit unsigned integer, decremented by 1 by each node that forwards the packet. The packet is discarded if Hop Limit is decremented to zero.
• Source Address: 128-bit address of the originator of the packet.
• Destination Address: 128-bit address of the intended recipient of the packet.

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IPv6
• IPv4 Address Allocation - 1998
• Holes in v4 Address Space
• Each pixel represents a /24
• Routing tables were used to generate yellow portions of the table – routable addresses
– Incomplete view of the entire Internet
• Packet traces were used to generate black portions of the table – source/destination addresses
– Raises more questions than it answers
• Class A’s allocated to companies, etc. used for internal routing only (?)
• Class B & C allocation from lowest to highest
• Reserved address space
• Unallocated space
IPv6 Background
• IP has been patched (subnets, supernets) but there is still the fundamental 32 bit address limitation
• IETF started effort to specify new version of IP in 1991
– New version would require change of header
– Include all modifications in one new protocol
– Solicitation of suggestions from community
– Result was IPng which became IPv6
– First version completed in ’94
• Same architectural principles as v4 – only bigger J
– IPv6 planned support list
• 128-bit address space
– This is what it’s all about…
• Real-time/QoS services
Security and authentication
• Autoconfiguration
– Hosts autoconfig with IP address and domain name
– Idea is to try to make systems more plug-n-play
• Enhanced routing functionality eg. Mobile hosts
• Multicast
• Protocol extensions
• Smooth transition path from IPv4
– Can’t do it all at once!
Address Space and Notation
• Allocation is classless
– Prefixes specify different uses (unicast, multicast, anycast)
• Anycast: send packets to nearest member of a group
– Prefixes can be used to map v4 to v6 space and visa-versa
– Lots of flexibility with 128 bits!
• ~1500 address/sqft of the earths surface
• Standard representation is set of eight 16-bit values separated by colons
– Eg. 47CD:1234:3200:0000:0000:4325:B792:0428
– If there are large number of zeros, they can be omitted with series of colons
• Eg. 47CD:1234:3200::4325:B792:0428
– Address prefixes (slash notation) are the same as v4
• Eg. FEDC:BA98:7600::/40 describes a 40 bit prefix
• Address Prefix Assignments
Unicast Assignment in v6
• Unicast address assignment is similar to CIDR
– Unicast addresses start with 001
– Host interfaces belong to subnets
– Addresses are composed of a subnet prefix and a host identifier
– Subnet prefix structure provides for aggregation into larger networks
• Provider-based plan
– Idea is that the Internet is global hierarchy of network
– Three levels of hierarchy – region, provider, subscriber
– Goal is to provide route aggregation to reduce BGP overhead
• A provider can advertise a single prefix for all of its subscribers
– Region = 13 bits, Provider = 24 bits, Subscriber = 16 bits, Host = 80 bits
• Eg. 001,regionID,providerID,subscriberID,subnetID,intefaceID
– What about multi-homed subscribers?
• No simple solution
• Anycase addresses are treated just like unicast addresses
– It’s up to the routing system to determine which server is “closest”
• Recall IPv4 Packet Format Details
• IPv6 Packet Format
• Packet Format Details
• Simpler format than v4
• Version = 6
• Traffic class same as v4 ToS
• Treat all packets with the same Flow Label equally
– Support QoS and fair bandwidth allocation
• Payload length does not include header –limits packets to 64KB
– There is a “jumbogram option”
• Hop limit = TTL field
• Next header combines options and protocol
– If there are no options then NextHeader is the protocol field
• Options are “extension header” that follow IP header
– Ordered list of tuples – 6 common types
• Quickly enable a router to tell if the options are meant for it
– Eg. routing, fragmentation, authentication encryption…
Key differences in header
• No checksum
– Bit level errors are checked for all over the place
• No length variability in header
– Fixed format speeds processing
• No more fragmentation and reassembly in header
– Incorrectly sized packets are dropped and message is sent to sender to reduce packet size
– Hosts should do path MTU discovery
– But of course we have to be able to segment packets!
• What about UDP packets?
– Fragmentation Extension
• Similar to v4 fragmentation
– Implemented as an extension header
• Placed between v6 header and data (if it is the only extension used)
– 13 bit offset
– Last-fragment mark (M)
– Larger fragment ID field than v4
• Fragmentation is done on end host
Routing Extension
• Without this header, routing is essentially the same as v4
• With this header essentially same as the source routing option in v4
– Loose or strict
• Header length is in 64-bit words
• Up to 24 addresses can be included
– Packet will go to nearest of these in “anycast” configuration
• Segments left tracks current target
• Transition from v4 to v6
Flag day is not feasible
• Dual stack operation – v6 nodes run in both v4 and v6 modes and use version field to decide which stack to use
– Nodes can be assigned a v4 compatible v6 address
• Allows a host which supports v6 to talk v6 even if local routers only speak v4
• Signals the need for tunneling
• Add 96 0’s (zero-extending) to a 32-bit v4 address – eg. ::10.0.0.1
– Nodes can be assigned a v4 mapped v6 address
• Allows a host which supports both v6 and v4 to communicate with a v4 hosts
• Add 2 bytes of 1’s to v4 address then zero-extend the rest – eg. ::ffff:10.0.0.1
• Tunneling is used to deal with networks where v4 router(s) sit between two v6 routers
– Simply encapsulate v6 packets and all of their information in v4 packets until you hit the next v6 router
IPv6 Issues
• Address length: usable addresses vs. overhead
• Hop limit: is 65K necessary?
• Max. Pkt. Size: Larger BW calls for larger pkts.
• Is the checksum necessary?
• How do servers handle both types of packets?
• Is security necessary in IP?
– How is it best implemented?
• DNS can be very important in the transition – how?

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IPV6Internet Protocol Version 6
The new way for internet technology.
 5 things you should know about IPv6 Many web surfers don't know it, but the introduction of new internet address standards might change the way they get online. since the supply of usable addresses governed by the IPv4 standard (internet protocol, version 4) has been exhausted, IPv6 has now been introduced. This will allow a previously impossible variety of addresses, says Christoph Meinel, a professor at Germany's Hasso Plattner Institute. But what does this change mean for everyday surfers? Here's an overview. 
    What is the difference between IPv4 and IPv6? Until now, IP addresses have been assigned in blocks of four numbers with up to three numerals each: 217.79.215.248, for example. The new IPv6 standard won't convert the numbers into the decimal system, rather a hexadecimal system, recognized by its combination of numbers and letters. The new standard can be recognized by its eight blocks, separated by colons -- 2001:db8:0:0:0:0:1428:57ab, for example. 
    Why are IP addresses necessary? In order for internet-capable devices to share information, they need a unique machine-readable address. These addresses are assigned based on a standard of internet protocols.But, since humans have a hard time remembering these strings of numbers, websites are also labelled with domain names, like google.com. When these addresses are typed into browsers, special servers translate them into IP addresses for the benefit of the computers.  
   Will my PC be able to process new standard? In most cases, yes. But an IPv6-capable operating system is a prerequisite. Those can be found in any Windows system post Vista. There are ways to install 
   Will my DSL access support the new standard? In most cases, no. Contemporary routers, like the ones provided by telecommunications companies when DSL packages are ordered, are still set for the old IPv4 standard. In some cases, IPv6 can be added with a firmware update. When purchasing a new router, make sure it supports IPv6. 
 Will there be problems during transition? Generally, no. Internet use shouldn't be affected after the switch -- at least that's what providers are promising. Those providers have modified their network so that data packets reach all users whether they are using IPv4 or IPv6 standards, a method called dual-stack application. Alternatively, software solutions, like those based on tunnel technology, can be used. Basically... IPv4 was 32 bits long and IPv6 is 128 bits. IPv6 also has security built in. It also has Auto Configuration. Almost all the OS in market today supports IPv6 even Windows XP. Don't worry it will still take time for end users to get an IPv6 Addresses. All I believe is Large service providers will start implementing it in their network and will still use IPv4 to IPv6 tunnelling. 
       Advantages Of Using IPV6 It's an internal protocol change,since the V4 IP's are depleted now and no more new IP's can be assigned, hence they are switching to the V6. And yea, no prior knowledge is required, since most DSLs/Routers are selected on 'Auto-Assign', but if your as using manual IP, the internet service provider will need to come and personally change the configuration according to the assigned protocol. Users dont need to know the details at all There is nothing to worry about IPv6 switch over.vista and 7 are compatible for IPv6.for other OS there might be a firmware upgrade or software for compatibility mode.if you want make sure about IPv6 in vista or Win 7 go to properties of Local Area Connection there you can see both IPv4 and IPv6 protocol Its better. It increases the network scalability.