Network improvement has become follower in today's modern life. The more we work the more we are affected to network and thus normally having always new requirements. To implement more efficient methods is needed first to predicate them. This predication needs to be developed before the requirements are very high. Users always expect more from networking while they compare old and current methods they're working on. If network improvement performs poorly it would damage many businesses, consumer satisfaction etc, thus forthcoming of network should always be improved and not go down. One of the greatest improvements made on network field was inventing a new version of Internet Protocol (version 6), which in comparison with the current Internet Protocol - Version 4, provides more internet growth and in number of users 1 and functionality. The possibility for each device to have a permanent IP. Internet Protocol version 4 or IPv4 is the first version of Internet Protocol (IP) to become widely deployed. It is a data-oriented protocol and is used on a packet switched network, such as Ethernet. It is described as a best effort delivery protocol which means that it does not guarantee data delivery, assure data arriving in proper order, or avoid duplicate data delivery. IPv4 does provide data integrity by the use of packet checksums.
Internet Protocol version 6 or IPv6 is also an Internet Layer protocol for packet switched networks. IPv6 has a much larger address space than IPv4. The new address length is 128 bits. This will eliminate the problem with IPv4, the need for network address translation to avoid address exhaustion.
IPv6
The popularity of the Internet today and its complex spaghetti junction of wires, connections, delivery mechanisms and addresses could not have possibly reached the outer limits of the imaginations of the Internet's forefathers.This huge growth in Internet use has not only led to increased demand for better, faster technology, but has also increased the demand for addresses from which to send and receive
Information.This is especially true for developing countries where people are only really starting to use the Internet. Internet Protocol version 6 or IPv62 is an improved version of the current and most widely used Internet Protocol, IPv4. IP enables data to be sent from one computer to another in a network and is known as a connectionless protocol because there is no continuous connection between the two communicating devices. So, when a message is sent via IP it is broken up into packets, which may travel via a number of different routes to their final destination, and on arrival at their destination they are reassembled in their original form. Each device in a network has an IP address, which is used by the IP protocol to ensure that the packets of information reach their correct destination. IPv4 was the first commercial version of IP and is now being replaced with IPv6 (also known as Ping, IP next generation).The key feature of IPv6 is its extra address space from the IPv4's 32 bits to 128 bits, which increases the number of available IP addresses from 4 billion to over 340 trillion .
Address depletion has been the primary driver behind the need for IPv6, but it is also driven by the demand for wireless devices, which, because they access the Internet, require their own IP addresses. The explosion in the use of handheld wireless devices is evidenced by their predicted shipment numbers, which is expected to grow from 430m in 2002 to 760m in 2006, and mobile Internet users are expected to exceed 1.2 billion before the end of the decade3. The increasing number of Internet users, systems, and the convergence of services into common infrastructure will drive the demand for IPv6.
The commercial opportunities that IPv6 can provide for wireless devices, peer-to-peer networking and the "smart home" are also driving the move to the new technology.The wireless market requires a low latency, always on, auto-roaming always-reachable IP service. Peer-to-peer networking enables a group of computers to communicate directly with each other, rather than through a central server, in order to avoid the expense and delay of handling all the traffic on a server. Peer-to-peer networking4 is used for multiplayer online games, IPtelephony, video-conferencing and new business models similar to Napster. In addition, other commercial opportunities for "smart home" products, such as Internet enabled automobiles, security systems and kitchen appliances are also pushing the transition to IPv6.
In some countries, the pressures associated with address depletion, combined with these commercial opportunities, have resulted in governments mandating the move to IPv6.The European Commission as well as the Japanese, Taiwanese and Korean governments have mandated the move and other Asian countries are working towards it. The United States has been somewhat slower to take up IPv6, although the US Department of Defense has indicated it aims to complete it's by 2008.
IPv4:
IPv4 was the first version of Internet Protocol to be widely used, and accounts for most of today's Internet traffic. There are just over 4 billion IPv4 addresses. While that is a lot of IP addresses, it is not enough to last forever. IPv4 is a connectionless protocol used for packet-switched Link Layer networks (e.g., Ethernet). It operates on a best effort delivery model; which does not guarantee delivery, nor does it assure avoidance of duplicate delivery or proper sequencing. These aspects, includes data integrity, and are addressed by an upper layer transport protocol.
IPv4 uses 32-bit (four-byte) addresses, limiting the address space to 4,294,967,296 (232) with unique addresses possible. However, some of these addresses are reserved for special purposes such as multicast addresses (~270 million addresses) or private networks (~18 million addresses), resulting in reduction of number of addresses that can potentially be allocated for routing across the public Internet. An IPv4 address shortage has been developing because addresses are being incrementally delegated to end users. Network addressing architecture is redesigned via class full network design, Network address translation (NAT), and Classless Inter-Domain Routing, have contributed to delay significantly the inevitable exhaustion; but on February 3, 2011, primary address pool of IANA was exhausted when the last 5 blocks were allocated to the 5 regional Internet registries (RIRs).
Virtual private networks
A virtual private network (VPN) is a secure way of connecting to a private Local Area Network at a remote location, using the Internet or any insecure public network to transport the network data packets privately, using encryption. The VPN uses authentication to deny access to unauthorized users, and encryption to prevent unauthorized users from reading the private network packets. The VPN can be used to send any kind of network traffic securely, including voice, video or data.
VPNs are frequently used by remote workers or companies with remote offices to share private data and network resources. VPNs may also allow users to bypass regional internet restrictions such as firewalls, and web filtering, by "tunneling" the network connection to a different region.
Technically, the VPN protocol encapsulates network data transfers using a secure cryptographic method between two or more networked devices which are not on the same private network, to keep the data private as it passes through the connecting nodes of a local or wide area network.
Link-local addressing
RFC 5735 is defining an address block, 169.254.0.0/16, used for a special purpose in link-local addressing. These addresses are valid only on the links, such as a local network segment or point-to-point connection, that the host is connected to. Over the internet either in source or destination, packets can't be routed as in the case of private addresses. The primary usage of Link-local addresses is an IP address which is used for communicating over the network within local subnet. Link local address is an IP address which is automatically assigned to a device when there is no other method assigned to it such as DHCP.
"Automatic Private Internet Protocol Addressing (APIPA) is a common alternative to the use of the Dynamic Host Configuration Protocol (DHCP) to request and retrieve an Internet Protocol (IP) address for a host. APIPA simplifies the assignment of IP address and subnet-mask configuration information to hosts in small networks. When APIPA is used, the operating system allows the assignment of a unique IP address to each station on a small local area network (LAN). This avoids the administrative overhead of running a DHCP server or manually setting IP configuration information." (Microsoft)
The websites are usually not recognized by IP addresses, but by names (e.g., www.microsoft.com, www.usa.gov, www.ets.org, www.ucmo.edu). The routing of IP packets over the Internet are not directed by such names, but by the numeric IP addresses that are assigned to such domain names. This requires translating (or resolving) domain names to addresses.
The Domain Name System (DNS) provides such a system for converting names to addresses and addresses to names. The DNS naming is also hierarchical like CIDR addressing and allows for sub delegation of name spaces to all other DNS servers.
The domain name system is often described as an analogy to the telephone system directory information systems in which all subscriber names are translated to telephone numbers
Basic differences between IPv4 and IPv6.
The transition from IPv4 to IPv6 is one of evolution rather than revolution, so for an extended period of time both IPv4 and IPv6 will coexist. The transition will be gradual because many users have large installed equipment bases and replacing these at one time would be costly even when considering the significant benefits of IPv6. Furthermore, there are a number of "band aids", such as NAT, that have been designed to extend the life of IPv4, but they will only temporarily slow the drive to IPv6 and will certainly not prevent IPv6 becoming the IP of choice. The remainder of this paper provides a technical overview of IPv6 and describes Allied Telesis'
Proactive approach to the IPv6 evolution.
Simplified header format. IPv6 has a fixed length header, which does not include most of the options an IPv4 header can include. Even though the IPv6 header contains two 128 bit addresses (source and destination IP address) the whole header has a fixed length of 40 bytes only. This allows for faster processing.
Options are dealt with in extension headers, which are only inserted after the IPv6 header if needed. So for instance if a packet needs to be fragmented, the fragmentation header is inserted after the IPv6 header. The basic set of extension headers is defined in RFC 2460.
IPv4 is 32 bits IP address that we use commonly; it can be 192.168.8.1, 10.3.4.5 or other 32 bits IP addresses. IPv4 can support up to 232 addresses, however the 32 bits IPv4 addresses are finishing to be used in near future, so IPv6 is developed as a replacement. IPv6 is 128 bits, can support up to 2128 addresses to fulfill future needs with better security and network related features.
A lot of the new IPv6 functionality is built into ICMPv6 such as Neighbor Discovery, Auto configuration, Multicast Listener Discovery, Path MTU Discovery.
Enhanced Security and QoS Features.
IPv6 makes the router's task simpler compared to IPv4.
IPv6 is better suited to mobile networks than IPv4.
IPv6 addresses are represented in a hexadecimal, colon-separated notation, while IPv4 address use the dot-decimal notation.
IPv6 allows for bigger payloads than what is allowed in IPv4.
IPv6 is used by less than 1% of the networks, while IPv4 is still in use by the remaining 99%.
Advantages of IPv6 over IPv4.
Internet Protocol Version 6 (IPv6) is the next generation Internet protocol standard. Current Internet Protocol Version 4 (IPv4) is used as a standard Internet protocol. IPv4 is a well-designed protocol but lacks features to be used in the fast-growth Internet world.
Following are some of the advantage of IPv6 over IPv4:
1. Larger Address Space: address filed in IPv6 is 128 bits long while the address filed of IPv4 is only 32 bits in length. IPv6 offers very large, i.e.296 address space as compared to IPv4.
2. Better header format: the header of IPv6 has been designed in a way to speed-up the routing process. In header of IPv6 options are separated from the base header. Options are inserted into base header only when required by the upper-layer data.
3. Provision for extension: IPv6 has been designed in a way that a protocol can be extended easily to meet the requirements of emerging technologies or new applications.
4. Resource Allocation support in IPv6: IPv6 provides a mechanism called Flow Label for resource allocation. Flow label enables source to send request for the special handling of a packet. This mechanism is really helpful in real-time audio and video transmission.
5. Security Features: to ensure confidentiality and packet's integrity encryption and authentication options are included in IPv6
IPv6 Implementations:
IPv6 is already widely deployed in Japan. IPv6 was trialed as a way of monitoring traffic by installing detectors in cars. Quickly seeing the potential of this technology, one Tokyo taxi company uses IPv6 technology to keep its customers dry. When it rains on one of their taxis and the windscreen wipers are turned on, detectors on the wipers send a message to the company's headquarters. From this message, the company can locate the taxi and dispatch more taxis to that area in anticipation of more people also wanting to stay dry.
Single Subnet with Link-Local Addresses: This implementation supports the installation of the IPv6 protocol on at least two nodes on the same network segment without intermediate routers. A network segment is also known as a link or subnet. The following illustration shows the implementation of two nodes on a single subnet using link-local addresses.
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By default, the IPv6 protocol for Windows Mobile configuration settings will link-local addresses for each interface that corresponds to installed network interface adapters.
Link-local addresses have the prefix of FE80: /64. The link-local address of a node is the combination of the prefix FE80: /64 and the 64-bit interface identifier are expressed in colon-hexadecimal notation. The interface identifier is the last 64 bits in the IPv6 address, and it is derived from the 48-bit Ethernet MAC address of that network adapter. This is discussed in detail with examples are provided in IPv6 Interface Identifiers
IPv6 Traffic between Nodes on Different Subnets of an IPv6 Internetwork:
This implementation requires three computers (two hosts and one router computer) and additional router beyond the installation of the IPv6 protocol. This implementation includes two separate network segments (also known as links or subnets), and an IPv6-capable router that connects the network segments and forwards IPv6 packets between the hosts. The following illustration shows the implementation.
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By default, the IPv6 protocol for Windows CE .NET 4.1 and later configures link-local addresses for each interface that corresponds to installed network interfaces, such as Ethernet network adapters.
Link-local addresses have the prefix of FE80::/64. The link-local address of a node is the combination of the prefix FE80: /64 and the 64-bit interface identifier expressed in colon-hexadecimal notation. The interface identifier is the last 64 bits of the IPv6 address, and is derived from the 48-bit Ethernet MAC address of the network adapter. This is described in detail and examples are provided in IPv6 Interface Identifiers.
With link-local addresses, Host A and Host B can communicate with the router computer, but not with each other. In this implementation, the router advertises additional site-local prefixes. Host A and Host B use these prefixes to automatically configure site-local addresses that are derived from the 48-bit Ethernet MAC address of the network adapter. After Host A and Host B have site-local addresses, they can communicate with each other.
IPv6 Traffic between Nodes on Different Subnets of an IPv4 Internetwork:
IPv6 traffic that is carried as the payload of an IPv4 packet (treating the IPv4 infrastructure as an IPv6 link-layer) is still IPv6 traffic. You can test IPv6 functionality for your applications without the deployment of IPv6 routers.
The following table shows the methods that the IPv6 protocol for Windows Embedded CE provides for communicating between IPv6 nodes on different subnets of an IPv4 internetwork.
Communication method
Description
Intrasite Automatic Tunnel Addressing Protocol (ISATAP) addresses
ISATAP is an address assignment and tunneling mechanism that can be used for communication between IPv6 and IPv4 nodes on an IPv4 network. ISATAP tunneling is described in the Internet draft draft-ietf-ngtrans-isatap-00.txt.
6to4
6to4 allows communication between separate IPv6-enabled 6to4 sites. 6to4 hosts using the IPv6 protocol can also use 6to4 addresses and 6to4 tunneling to communicate across an IPv4 intranet or the Internet.
For more information, see IPv6 Traffic Between Nodes in Different Sites Across the Internet (6to4).
Applications that use the addresses associated with these methods are using the same Windows Sockets functions as if global IPv6 addresses and an IPv6 infrastructure were being used.
Present & Future of IPv6
The introduction of protocol Classless Inter-Domain Routing (CIDR) in the Internet routing and IP address allocation methods in 1993 and the extensive use of network address translation (NAT) delayed the inevitable IPv4 address exhaustion. Final exhaustion occurred on February 3, 2011
In 2008, IPv6 accounted for a minuscule fraction of the used addresses and the traffic in the publicly-accessible Internet which is still dominated by IPv4. In October 2010, 243 (83%) of the 294 top-level domains (TLDs) in the Internet supported IPv6 to access their domain name servers, and 203 (69%) zones contained IPv6 glue records, and approximately 1.4 million domains (1%) had IPv6 address records in their zones. Of all networks in the global BGP routing table, 7.2% have IPv6 protocol support.
The 2008 Summer Olympic Games were a notable event in terms of IPv6 deployment, being the first time a major world event has had a presence on the IPv6 Internet at http://ipv6.beijing2008.cn/en and all network operations of the Games were conducted using IPv6. At the time of the event, it was believed that the Olympics provided the largest showcase of IPv6 technology since the inception of IPv6. Since that time, major providers of Internet services, such as Google, have begun to implement IPv6 access into their products.
Cellular telephone systems present a large deployment field for Internet Protocol devices as mobile telephone service is being transitioned from 3G systems to next generation (4G) technologies in which voice is provisioned as a Voice over Internet Protocol (VoIP) service. This mandates the use of IPv6 for such networks. In the U.S., cellular operator Verizon has released technical specifications for devices operating on its future networks. The specification mandates IPv6 operation according to the 3GPP Release 8 Specifications (March 2009) and deprecates IPv4 as an optional capability. [
Some implementations of the Bit Torrent peer-to-peer file transfer protocol make use of IPv6 to avoid NAT issues common for IPv4 private networks.
All major operating systems in use as of 2010 on personal computers and server systems have production quality IPv6 implementations. Microsoft Windows has supported IPv6 since Windows 2000, and in production ready state beginning with Windows XP. Windows Vista and later have improved IPv6 support. Mac OS X Panther (10.3), Linux 2.6, FreeBSD, and Solaris also have mature production implementations.
