When we use the Internet for any activity, be it e-mail, data transmission, web browsing, downloading files, images or videos or any other service or application, communication between different network elements and our own computer, laptop or smart phone, uses a protocol: The IP (Internet protocol) which specifies the technical format of packets and the addressing scheme for computers to communicate over a network.
IPv6 (Internet protocol version 6) is the most recent version of the IP, the communications protocol that provides an identification and location system for computers on networks and routes traffic across the Internet.
In order to connect any device to Internet it’s necessary to provide an IP address to the device. The first version of an Internet Protocol publicly used was IPv4 (Internet protocol version 4). This protocol was created by the Defense Advanced Research Projects Agency (DARPA). DARPA is an agency of the U.S. Department of Defense responsible for the development of emerging technologies mainly for military applications created in 1958. IPv4 included an addressing system that used numerical identifiers consisting of 32 bits. The use of addresses with a length of 32 bits limits the total number of possible addresses to a number of approximately 4.3 billion addresses for devices connected to internet around the world. The number of devices connected to Internet will be soon bigger than the number of addresses provided by IPv4. For this reason, and in anticipation of the situation, the agency responsible for standardization of Internet protocols: The IETF (Internet Engineering Task Force) has been working in a new IP version from 1998: The IPv6, the successor protocol that is intended to replace IPv4 was first formally described in Internet standard document RFC 2460 [3].
IPv6 uses a 128-bit address format, allowing 2128, or approximately 3.4 1038 addresses, approximately 8 1028 times as many as IPv4. While increasing the pool of addresses is one of the most important benefits of IPv6, there are other important technological changes in IPv6 that will improve the IP protocol: easier administration, better multicast routing, a simpler header format and more efficient routing, built-in authentication and privacy support among others.
IPv6 will coexist with the older IPv4 for some time. The deployment of IPv6 will be made gradually in an orderly coexistence with IPv4. Client devices, network equipment, applications, content and services are to be adapted to the new Internet protocol version IPv6. Moreover, the transition from IPv4 to IPv6 will establish a common set of standards between companies, educational systems, around the world.
IPv6 addresses are represented as eight groups of four hexadecimal digits. These groups are separated by colons, but methods to abbreviate this full notation exist. The IPv6 header format is shown by Fig. 1.
Structure of IPv6 Header |
|
Version |
4-bit Internet Protocol version number = 6. |
Traffic Class |
8-bit traffic class field. |
Flow Label |
20-bit flow label. |
Payload Length |
16-bit unsigned integer. Length of the IPv6 payload, i.e., the rest of the packet following this IPv6 header, in octets. |
Next Header |
8-bit selector. Identifies the type of header immediately following the IPv6 header. Uses the same values as the IPv4 protocol field |
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 |
Address 128-bit address of the intended recipient of the packet (possibly not the ultimate recipient, if a routing header is present). |
The new features introduced with the IPv6 protocol are basically the following : A new header format, an efficient and hierarchical addressing and routing infrastructure, a much larger address space and stateless and both firewall address configuration, IP security, extensibility, a better Quality of Service (QoS) support and a new protocol for neighboring node interaction.
The IPv6 protocol has solved some of the security problems found in IPv4 networks by adding the IPsec (IP security) as mandatory. As a result, IPv6 is more efficient. IPsec enhances the original IP protocol by providing authenticity, integrity, confidentiality and access control to each IP packet through the use of two protocols: AH (authentication header) and ESP (encapsulating security payload).Moreover, the expansion of the number of bits in the address field to 128 bits offered by IPv6 creates a significant barrier for attackers wanting to conduct comprehensive port scanning. On the other hand, it is possible to bind a public signature key to an IPv6 address: CGA (Cryptographically Generated Address).
IPv6 offers also improvements on mobility security. Despite that the MobileIP Internet protocol is available in both IPv4 and IPv6, in IPv6 it was built into the protocol instead of being added as a new function in IPv4. This means that any IPv6 node can use a mobile IP both as required. Mobile IPv6 uses two extensions headline: A routing header for registration and a headline target to data delivery between mobile nodes and their corresponding fixed nodes.