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IETFÂ IPv6Â WGÂ beganÂ inÂ earlyÂ 1990Â for solvingÂ addressingÂ growth issues,Â butÂ CIDR, NAT, DHCPÂ andÂ PPPÂ haveÂ beenÂ developed, someÂ recoveryÂ address.Â TheÂ RIR systemÂ was introduced;Â the brakesÂ wereÂ putÂ on the consumption ofÂ IPv4Â addresses.Â IPv4Â 32Â bits =Â 4 billionÂ hosts.Â A needÂ forÂ IPv6Â isÂ the general perceptionÂ that "IPv6Â hasÂ notÂ yetÂ takenÂ hold firmly."Â IPv4Â addressÂ shortage isÂ notÂ yetÂ upon usÂ in the private sectorÂ requiresÂ a business case forÂ infrastructure dataÂ withoutÂ threadÂ emergedÂ recently, butÂ reality seems much betterÂ for yearsÂ toÂ come!
1.1. IP Network Addressing
INTERNET is 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 Classfull addressing does not allow the address space to be used to its maximum potential.
1.2. Classfull 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
Divided into 5 classes
Class A 8 bits N/W id and 24 bits host id and so on Class B, C. Wastage of IP addresses by assigning blocks of addresses which fall along octet boundaries.
1.3. Techniques to reduce address shortage in IPv4
Classless Inter Domain Routing (CIDR)
Network Address Translation (NAT)
Three-level hierarchy: network, subnet, and host. The extended-network-prefix is composed of the Classfull network-prefix and the subnet-number. The extended-network-prefix has traditionally been identified by the subnet mask.
1.3.2. Classless Inter-Domain Routing
Eliminates traditional Classfull IP routing,
Supports the deployment of arbitrarily sized networks, Routing information is advertised with a bit mask/prefix length and specifies the number of leftmost contiguous bits in the network portion of each routing 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 Boolean 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 .In this way Classless Inter Domain Routing is done.
1.3.3. Network Address Translation
Each organization has given single IP address and within organization each host with IP unique to the origin, from reserved set of IP addresses.
3 Reserved ranges
10.0.0.0 - 10.255.255.255 (16,777,216 hosts)
172.16.0.0 - 172.31.255.255/12 (1,048,576 hosts)
192.168.0.0 - 192.168.255.255/16 (65,536 hosts)
2. Comparisons to IPv4
2.1. Larger Address Space
The most important feature of IPv6 address space in IPv4 is greater than Size of IPv6 128 bits versus 32 bits in IPv4.Â Address space is conducive to 2128, about 1038 Ã- 34 addresses.Â .While people living in each of these figures are impressive for approximately 5 Ã- 1028 addresses this amount, the IPv6 address space to ensure the intent of the designers was not useful addressesÂ with geographic saturation.Â Enable efficient route aggregation, and implementation of specific addresses, on the contrary, more and more to simplify address allocation answered.Â In IPv4, complex classless inter domain routing methods (CIDR) to make the best use of the small size of the address space has been developed.Â IPv6 in the size of a subnet still 264 addresses, the IPv4 address space, which is 232 square-shaped. Thus, IPv6 address space using the actual rate would be small, but network management and routing efficiency is improved by space subnet aggregation and major channels.
Prefix different route with a new contact the provider with an existing Renumbering IPv4 networks is a big effort.Â With IPv6, however, change the prefix in principle announced by some routers host identifiers (64 least significant bits of an address) can do is a complete network can be configured independently by auto a facility.
2.2. Stateless address auto configurationÂ (SLAAC)
IPv6 hosts can configure themselves automatically when connected to a routed IPv6 network usingÂ Internet Control Message Protocol version 6Â (ICMPv6) router discovery messages. When first connected to a network, a host sends aÂ link-localÂ router solicitation multicast request for its configuration parameters; if configured suitably, routers respond to such a request with a router advertisement packet that contains network-layer configuration parameters. If IPv6 stateless address auto configuration is unsuitable for an application, a network may use stateful configuration with theÂ Dynamic Host configuration Protocol version 6Â (DHCPv6) or hosts may be configured statically.
Sent a packet to multiple destinations at one of the multicast transmission, IPv6 is part of the basic specification.Â Once implemented this functionality in IPv4 option.Â IPv6 multicast addresses and multicast protocols of IPv4 are common with shared characteristics, but also eliminating the need for some protocol provides for the change and improvement.Â IPv6 is not implemented in traditional IP broadcast a special broadcast address using the attached link, namely the transmission of a packet to all hosts, and thus does not define the broadcast address.Â IPv6 in the same outcome link-local all nodes multicast group FF02 know by sending a packet may be obtained: 1, which is similar to multicast address 220.127.116.11 IPv4.Â IPv6 is the IPv6 multicast group, the cross-domain solutions easier to deploy new multicast solutions including integration Rendezvous Point address.
InÂ IPv4,Â itÂ wasÂ veryÂ difficultÂ forÂ organizationsÂ to obtainÂ globallyÂ routableÂ evenÂ aÂ multicast groupÂ allocationÂ andÂ implementationÂ ofÂ cross-domainÂ solutionsÂ isÂ veryÂ obscure.Â TheunicastÂ address allocationÂ byÂ aÂ local internetÂ registryÂ forÂ IPv6Â hasÂ at leastÂ oneÂ 64-bitprefixÂ routing,Â whichÂ givesÂ theÂ smallestÂ sizeÂ availableÂ subnetÂ in IPv6Â (alsoÂ 64Â bits).Â With such an assignment, itÂ isÂ possible toÂ integrate theÂ unicastÂ address prefixÂ in theÂ formatÂ ofIPv6 multicastÂ addresses,Â whileÂ providingÂ aÂ blockÂ of 32Â bits,Â theÂ least significant bitsÂ of theÂ address,Â or aboutÂ 4.2Â billionÂ multicast groupÂ identifiers.Â Thus,Â eachÂ userÂ ofÂ anÂ IPv6 subnetÂ isÂ automaticallyÂ available aÂ set ofÂ multicast groupsÂ universallyÂ accessibleÂ source-specificÂ multicastÂ applications.
Unlike mobile IPv4,Â mobile IPv6 avoids triangular routingÂ and is therefore as efficient as native IPv6. IPv6 routers may also support network mobility which allows entire subnets to move to a new router connection point without renumbering.
2.5. Mandatory support for network layer security
Internet Protocol SecurityÂ (IPSec) was originally developed for IPv6, but found widespread deployment first in IPv4, into which it was back-engineered. IPSec is an integral part of the base protocol suite in IPv6.IPSec support is mandatory in IPv6; this is unlike IPv4, where it is optional.
2.6. Options extensibility
IPv4 protocol header has a fixed size (40 octets) for option parameters.IPv6 in the Options IPv6 header, a full package of its size since the size limit as an additional extension header are implemented. Future services without redesigning the basic protocol extension header system, QoS, security, mobility, and others, provide support scalability.
IPv4 limits packets toÂ 65535Â (216Â - 1) octets of payload. IPv6 has optional support for packets over this limit, referred to asÂ jumbograms, which can be as large asÂ 4294967295Â (232Â - 1) octets. The use of jumbograms may improve performance over high-MTUÂ links. The use of jumbograms is indicated by the Jumbo Payload Option header
3. FEATURES OF IPV6
3.1. Expanded routing and addressingÂ
IPv6 increases the IP address size from 32 bits to 128 bits to support more levels of addressing
Hierarchy. In addition, IPv6 provides a greater number of addressable nodes. IPv6 also employs simpler auto configuration of addresses. The addition of aÂ scopeÂ field improves the scalability of multicast routing to multicast addresses. IPv6 defines a new type of address that is called anÂ anycastÂ address. An anycast address identifies sets of nodes. A packet that is sent to an anycast address is delivered to one of the nodes. The use of anycast addresses in the IPv6 source route allows nodes to control the path over which their traffic flows.
3.2. Header format simplificationÂ
Some fields or IPv4 header has been reduced. This can change in the overall situation of the processing package to reduce the cost of treatment. These changes, despite the increase in the size of the address, the IPv6 header as low as possible to keep the cost of bandwidth. IPv6 addresses are longer than the address of IPv4, although the four times larger size, IPv6 in IPv4 header, only twice the size of the head.
3.3. Improved support for optionsÂ
Changes in the way IP header options are encoded allow for more efficient forwarding. Also, the option length is less stringent limits. Changes in the future to introduce new options provide more flexibility.
3.4. Quality-of-service capabilitiesÂ
This capability enables the labeling of packets that belong to particular trafficÂ flowsÂ for which the sender requests special handling. For example, the sender can request non-default quality of service orÂ real-timeÂ service.
3.5. Authentication and privacy capabilitiesÂ
IPv6 includes the definition of extensions that provide support for authentication, data integrity, and confidentiality.
3.6. Can coexist with IPv4 network
There's no flag day, you can use existing devices. "Dual stack" devices that can use IPv4/IPv6 at the same time.
3.7. Vast amount of address space
2^32 or 2^13 route entries in ISP
2^64 nodes on a subnet
2^16 subnets to a site
3.8. Aggregation friendly
Core routes are limited to 8192 (2^13) by addressing architecture.
3.9. Auto configuration works beautiful
No server necessary, no wacky state management, Autoconfig available everywhere: IPv4 autoconfig required DHCP server
4. IPv6 Addressing
IPv6 address consists of the following types: unicast and multicast anycast.Â Unicast address identifies a single interface.Â Anycast to identify sets of interfaces.Â The package, which was sent to the anycast address, is delivered to team members.Â Multicast addresses identify a group of interfaces.Â The package, which is sent to the multicast address, is delivered to all interfaces in the group.Â In IPv6, multicast addresses are broadcast addresses change.Â The most important feature of the address space of IPv6 is that IPv4.Â IPv6 addresses are 128 bits, only 32 earlier.Â The IPv4 address space contains only 4.3 x 109 (4.3 million) addresses, IPv6 supports approximately 3.4 Ã- 1038 (340 undecillion) unique addresses, which are considered sufficient in the near futureÂ .IPv6 addresses are written in groups of four numbers separated by commas, e.g. 2001: db8: 1f70:: 999: de8: 7648:6 e8.Â IPv6 addresses are logically divided into two parts: 64-bit (sub-) network prefix, and a 64-bit interface identifier.Â IPv6 addresses are classified into three types of network methodologies: Unicast addresses identify each network device, anycast addresses identify
Group of interfaces, often in different locations, nearest is automatically selected, and multicast addresses are used to deliver the package several interfaces.Â Dipuziis method is not implemented in IPv6.Â Each IPv6 address is the scope, which indicates that the network is a unique and valid.Â Some of the unique addresses on the local market (sub-) network, others are unique.
Some IPv6 addresses are used for specific purposes, such as the loopback address.Â In addition, certain address ranges is considered special, as Link - use local addresses on the LAN, and only motions - the node multicast address is used Neighborhood Discovery Protocol.
4.1. IPv6 Auto configuration
4.1.1. Stateless address auto configuration
No resource management thanks to address architecture
Routers advertise info about the subnet
Hosts receive the information and configure it.
Stateful, needs server.
Stateless address auto configuration is much easier, and will be available everywhere
4.2. Address Format
IPv6 addresses have two logical parts: a 64-bit network prefix and a 64-bit host address part. (The host address is often automatically generated from the interface MAC address.) An IPv6 address is represented by 8 groups of 16-bit hexadecimal values separated by colons (:) shown as follows:
A typical example of an IPv6 address is
The hexadecimal digits are case-insensitive.
5. IPv6 Routing
Routing in IPv6 is almost identical to IPv4 routing under CIDR. The only difference is the addresses are 128-bit IPv6 addresses instead of 32-bit IPv4 addresses. With very straightforward extensions, all of IPv4's routing algorithms, such as OSPF, RIP, IDRP, IS-IS, can be used to route IPv6. IPv6 also includes simple routing extensions that support powerful new routing capabilities. The following list describes the new routing capabilities:
Provider selection that is based on policy, performance, cost, and so on,
Host mobility, route to current location
Auto-readdressing, route to new address
You obtain the new routing capability by creating sequences of IPv6 addresses that use the IPv6 routing option. An IPv6 source uses the routing option to list one or more intermediate nodes, or topological group, to beÂ visitedÂ on the way to a packet's destination. This function is very similar in function to IPv4's loose source and record route option. In order to make address sequences a general function, IPv6 hosts are required, in most instances, to reverse routes in a packet that a host receives. The packet must be successfully authenticated by using the IPv6 authentication header. The packet must contain address sequences in order to return the packet to its originator. This technique forces IPv6 host implementations to support the handling and reversal of source routes. The handling and reversal of source routes is the key that enables providers to work with hosts that implement the new features. The new features include provider selection and extended addresses.
6. IPv6 Packet format
Packet headerÂ andÂ payload,Â IPv6 packetÂ isÂ composedÂ of twoÂ parts.Â TitleÂ minimum functionality requiredÂ for allÂ packagesÂ with aÂ fixed partÂ consistsÂ ofÂ special featuresÂ and optional expansionÂ canÂ beÂ appliedÂ to stop.Â Fixed headerÂ forÂ IPv6 packetsÂ first 40Â bytes (320Â bits).Â The scopeÂ ofÂ the following header,Â andÂ toÂ presentÂ inÂ detailÂ inÂ aÂ series ofÂ extension pointsÂ toÂ theÂ next item.Â Upper layer protocolÂ ofÂ theÂ packet payloadÂ isÂ theÂ last fieldÂ points.Â Develop theÂ networkÂ packet headerÂ optionsÂ forÂ the special treatmentÂ is used toÂ move,Â route,Â asÂ for fission,Â andÂ usingIPSecÂ toÂ protectÂ structures.Â PayloadÂ withoutÂ special optionsÂ to aÂ sizeÂ of 64Â KB or larger can withÂ anÂ optionÂ ofÂ aÂ jumboÂ payloadÂ inÂ hop-by-hopÂ alternative titlesÂ expanded. FragmentationÂ isÂ handledÂ onlyÂ atÂ end pointsÂ ofÂ aÂ communication session, aÂ packet routersÂ neverÂ fragment, andÂ the host toÂ useÂ path MTUÂ discoveryÂ the sizeÂ ofÂ a packet throughÂ the communication channelÂ isÂ setÂ likelyÂ to choose.
6.1. Header comparison
7. Mobile IPv6
Mobile IP allows node to always be
Identified by its home address, regardless
Of its current point of attachment to the
Mobile IP is now fully integrated into IPv6.
It uses the destination header.
IPv6 provides many improvements over Mobile.
IPv4 Route optimization is built in IPv6
Eliminates the "triangle routing" problem in
Mobile IPv4, No need for foreign agents.
Neighbor discovery and auto configuration
Provides the required mechanisms for the
Mobile node. IPSec is used as the security mechanism available in all IPv6 implementation.
8. IPv6 Security Improvements
The current Internet has a number of security problems. The Internet lacks effective privacy and effective authentication mechanisms beneath the application layer. IPv6 remedies these shortcomings by having two integrated options that provide security services. You can use these two options either individually or together to provide differing levels of security to different users. Different user communities have different security needs.
The first option, an extension header that is called the IPv6Â Authentication HeaderÂ (AH), provides authentication and integrity, without confidentiality, to IPv6 datagram's. The extension is algorithm independent. The extension supports many different authentication techniques. The use of AH is proposed to help ensure interoperability within the worldwide Internet. The use of AH eliminates a significant class of network attacks, including host masquerading attacks. When using source routing with IPv6, the IPv6 authentication header becomes important because of the known risks in IP source routing. Upper-layer protocols and upper-layer services currently lack meaningful protections. However, the placement of the header at the Internet layer helps provide host origin authentication.
The second option, an extension header that is called the IPv6Â Encapsulating Security PayloadÂ (ESP), provides integrity and confidentiality to IPv6 datagram. Though simpler than some similar security protocols, ESP remains flexible and is algorithm independent. Similar security protocols include SP3D and ISO NLSP.
In order to reach the IPv6 Internet, an isolated host or network must use the existing IPv4 infrastructure to carry IPv6 packets. This is done using a technique known asÂ tunnelingÂ which consists of encapsulating IPv6 packets within IPv4, in effect using IPv4 as a link layer for IPv6.
The direct encapsulation of IPv6 datagram's within IPv4 packets is indicated by IP protocol number 41. IPv6 can also be encapsulated within UDP packets e.g. in order to cross a router or NAT device that blocks protocol 41 traffic. Other encapsulation schemes, such as used inÂ AYIYAÂ orÂ GRE, are also popular.
9.1. Automatic tunneling
AutomaticÂ tunnelÂ is aÂ techniqueÂ whereÂ the tunnelÂ endpointsÂ automaticallyÂ routing infrastructureÂ refers toÂ theÂ sets.Â RFCÂ 3056 is anÂ AutomaticÂ tunnel, the protocolÂ 41 encapsulationÂ recommendedÂ for using 6to4Â tunnel.Â TunnelÂ endpointsÂ atÂ theÂ remoteÂ side of well-knownÂ IPv4 anycastÂ addressÂ usingÂ IPv6 addressesÂ within theÂ IPv4 addressÂ onÂ the localÂ sideÂ are determinedÂ by embeddingÂ information.Â 6to4Â isÂ widelyÂ deployedÂ today.
TeredoÂ isÂ anÂ automaticÂ tunnelingÂ techniqueÂ thatÂ usesÂ UDP encapsulationÂ andÂ reportedly can crossÂ multipleÂ NATÂ boxes.Â IPv6,Â andÂ 6to4 tunneling TeredoÂ in Windows 7, including Windows Vista andÂ isÂ enabled by default.Â Native support forÂ mostÂ UnixÂ systemsÂ apply onlyÂ 6to4, but Teredo can be provided by third-party software such asÂ Miredo.
9.2. 6to4 Tunnels Over IPv4 Networks
To enable better transition from IPv4 to IPv6, SolarisÂ operatingÂ systemÂ nowÂ supports6to4Â transitionÂ mechanism.Â TheÂ systemÂ across the networkÂ aÂ differentÂ 6to4 IPv4Â andIPv6 inÂ aÂ tunnelÂ packetÂ from the siteÂ enablesÂ separateÂ IPv6Â sites.Â 6to4Â aÂ globalÂ IPv4 addressÂ toÂ useÂ yourÂ siteÂ toÂ getÂ aÂ fullÂ 48-bit IPv6Â enablesÂ globalÂ prefix.Â ToÂ obtain technical information aboutÂ 6to4Â routing, 3056, "IPv6 and IPv4Â domainÂ throughÂ a cloud of connection"Â refer toÂ RFC.
6to4Â is applicableÂ if eitherÂ orÂ bothÂ of the following conditionsÂ are present onÂ yourÂ IPv6siteÂ consider:3056, "Connection of IPv6 Domains via IPv4 Clouds".
Consider implementing 6to4 if either or both of the following conditions exist at your IPv6 site:
Your IPv6 site does not have an IPv6 connection to the Internet.
Your isolated IPv6 site needs to communicate with another isolated IPv6 site.
In the past, isolated IPv6 sites could not communicate with other IPv6 sites. 6to4 routing enables the isolated sites to transfer packets through a tunnel over an IPv4 network. The only requirement is a boundary router with a globally unique IPv4 address for the interface that connects to the IPv4 network.
You can configure more than one interface on a router for 6to4 support, provided that the interface meets the previously mentioned requirements. You do not need to manually configure hosts for 6to4 support. On receipt of a prefix advertisement from the 6to4 router, an IPv6 host automatically reconfigures an IPv6 interface with a 6to4 address.
The router encapsulates outbound IPv6 packets in an IPv4 header. An automatic tunnel is then constructed between the 6to4 router and the destination 6to4 site, over an IPv4 network. On receipt, the remote 6to4 router encapsulates the packets. The remote 6to4 router delivers the now standard IPv6 packets to the appropriate IPv6 nodes.
10. IPv6 Deployment
New infrastructures can build on IPv6 from start Deploy IPv6 nodes and applications.
New applications deployed within IPv6
Networks do not require proxies or NAT boxes. It is Simpler and less expensive to deploy new applications. IPv6 clients can access any IPv6 applications, services, content.
Not all applications are IPv6 ready (as of
Today, the Internet is still mostly IPv4).
IPv6 was designed from the beginning with transition mechanisms in mind (many tools are available), For example, application gateways can provide access to the IPv4 network services, typically, a dual stack (IPv4/IPv6) node Running application proxies (mail, web â€¦)
These gateways are used only when an IPv6
Client is requesting a service from an IPv4 only server.
In this paper we present a comparison study of IPv4 and IPv6 based approach to determine which version of Internet protocol is better and reliable, we concluded that:
IPv6 is NEW, built on the experiences learned from IPv4 IPv6 contains new features, large address space, new efficient header, and auto configuration, started in 1995, a lot of implementations and tests done.
This work is partly supported by Bahria University