Internet Protocol version 6 (IPv6) is the most recent version of the Internet Protocol (IP), the communications protocol that provides an identification and location system for computers on networks and routes traffic across the Internet. IPv6 was developed by the Internet Engineering Task Force (IETF) to deal with the long-anticipated problem of IPv4 address exhaustion. IPv6 is intended to replace IPv4.
The Need for Internet Protocol version 6 (IPv6)
IPv6 has a larger 128-bit address space, providing (340,282,366,920,938,463,463,374,607,431,768,211,456 to be exact) addresses. This provides roughly 50 octillion addresses per person alive on Earth today, or roughly 3.7 x 1021 addresses per square inch of the Earth’s surface. A lack of Internet addresses caused web programmes slow down. To allow the Internet to continue to grow and spread across the world, implementing IPv6 is necessary.
The depletion of IPv4 address space has been the motivating factor for moving to IPv6. IPv4 has a theoretical maximum of 4.3 billion addresses. With an increasing Internet population, a limited IPv4 address space, issues with NAT and an Internet of Everything. The time has come to begin the transition to IPv6.
IPv4 and IPv6 Coexistence
There is not a single date to move to IPv6. For the future, both IPv4 and IPv6 will coexist. The IETF has created various protocols and tools to help network administrators migrate their networks to IPv6. The migration techniques can be divided into three categories:
Dual Stack –A station must run IPv4 and IPv6 simultaneously until all the Internet uses IPv6. To determine which version to use when sending a packet to a destination to the source host queries the DNS. If the DNS return an IPv4 address, the source host sends an IPv4 packet. If the DNS return an IPv6 address, the source host sends an IPv6 packet.
Tunneling: is a strategy used when two computer using IPv6 want to communicate with each other and the packet must pass through a region that uses an IPv4. To pass through this region the packet must have an IPv4 address. So the IPv6 packet is encapsulated in IPv4 packet when it enters the region, and it leaves its capsule when it exits the region. It seems as if the IPv6 packet enters the tunnel at one end and emerges at other end.
Header Translation: sender wants to use Ipv6 but the receiver does not understand Ipv6
- Tunneling does not worked
- Must Ipv4 format to understood
- Header format totally changed
Benefits of IPv6
IPv6 offers the following features:
- Increased Address Space and Scalability – providing the absurd number of possible addresses stated previously.
- Integrated Security – provides built-in authentication and encryption into the IPv6 network header
- Compatibility with IPv4 – simplifies address migration, as IPv6 is backward-compatible with IPv4
IPv6 Address Representation
- An IPv6 address is represented as eight groups of four hexadecimal digits, each group representing 16 bits (two octets, a group sometimes also called a hextet). The groups are separated by colons (:).
- The hexadecimal digits are case-insensitive.
- The full representation of IPv6 have following techniques;
- Leading zeroes in a group may be omitted, but each group must retain at least one hexadecimal digit.
- Thus, the example address may be written as: 2001:db8:85a3:0:0:8a2e:370:7334
- One or more consecutive groups of zero value may be replaced with a single empty group using two consecutive colons (::)
- but the substitution may only be applied once in the address, because multiple occurrences would create an ambiguous representation.
- For example 2001:0db8:85a3:0000:0000:8a2e:0370:7334 can be written as 2001:db8:85a3::8a2e:370:7334
IPv6 Address Types
- Unicast – An IPv6 unicast address uniquely identifies an interface on an IPv6-enabled device
- Multicast – An IPv6 multicast address is used to send a single IPv6 packet to multiple destinations.
- Anycast – An IPv6 anycast address is any IPv6 unicast address that can be assigned to multiple devices. A packet sent to an anycast address is routed to the nearest device having that address.
World IPv6 Day and World IPv6 Launch Day
- World IPv6 Day was a technical testing and publicity event in 2011 sponsored and organized by the Internet Society and several large Internet content services to test and promote public IPv6 deployment.
- Following the success of the 2011 test day, the Internet Society carried out a World IPv6 Launch day on June 6, 2012 which, instead of just a test day, was planned to permanently enable IPv6 for the products and services of the participants
- Up till now 20 % of IPv6 has been deployed in the world and might be possible world will transit to IPv6 in early 2020 due to shortage of IPv4.
The IPv6 Prefix
- IPv4 utilizes a subnet mask to define the network “prefix” and “host” portions of an address.
- IPv6 always use CIDR notation to determine what bits notate the prefix of an address:
- Full Address: 1254:1532:26B1:CC14:123:1111:2222:3333/64 Prefix ID: 1254:1532:26B1:CC14: Host ID: 123:1111:2222:3333
- The /64 indicates that the first 64 bits of this address identify the prefix.