IPv4 vs IPv6
What is the difference between IPv4 and IPv6?
Internet Protocol Version 4 (IPv4)
The Internet Protocol Version 4 or also known as IPv4 is the widely or commonly used internet protocol version around the world.
IPv4 is a connectionless protocol for use on packet-switched Link Layer networks (e.g., Ethernet). It operates on a best effort delivery model, in that it does not guarantee delivery, nor does it assure proper sequencing or avoidance of duplicate delivery. These aspects, including data integrity, are addressed by an upper layer transport protocol (e.g., Transmission Control Protocol).
IPv4 uses 32-bit (four-byte) addresses, which limits the address space to 4,294,967,296 (232) possible unique addresses. However, some are reserved for special purposes such as private networks (~18 million addresses) or multicast addresses (~270 million addresses). This reduces the number of addresses that can potentially be allocated for routing on the public Internet. As addresses are being incrementally delegated to end users, an IPv4 address shortage has been developing. Network addressing architecture redesign via classful network design, Classless Inter-Domain Routing, and network address translation (NAT) have contributed to delay significantly the inevitable exhaustion; but on February 3, 2011, IANA’s primary address pool was exhausted when the last 5 blocks were allocated to the 5 regional Internet registries (RIRs).
This limitation has stimulated the development of IPv6, which is currently in the early stages of deployment, and is the only long-term solution.
IPv4 addresses may simply be written in any notation expressing a 32-bit integer value, but for human convenience, they are most often written in dot-decimal notation, which consists of the four octets of the address expressed separately in decimal and separated by periods.
Internet Protocol Version 6 (IPv6)
The Internet Protocol Version 6 or also known as IPv6, is a version of the Internet Protocol (IP) that is designed to succeed Internet Protocol version 4 (IPv4) and the only long-term solution of IPv4 address shortage or exhaustion. It was developed by the Internet Engineering Task Force (IETF). Like IPv4, IPv6 is an Internet Layer protocol for packet-switched internetworking and provides end-to-end datagram transmission across multiple IP networks. It uses 128-bit addresses, so the new address space supports 2128(approximately 340 undecillion or 3.4×1038) addresses.
This expansion allows for many more devices and users on the internet as well as extra flexibility in allocating addresses and efficiency for routing traffic. It also eliminates the primary need for network address translation (NAT), which gained widespread deployment as an effort to alleviate IPv4 address exhaustion.
It also implements additional features not present in IPv4. It simplifies aspects of address assignment (stateless address autoconfiguration) and network renumbering (prefix and router announcements) when changing Internet connectivity providers. The IPv6 subnet size has been standardized by fixing the size of the host identifier portion of an address to 64 bits to facilitate an automatic mechanism for forming the host identifier from link layer media addressing information (MAC address). Network security is also integrated into the design of the IPv6 architecture, and the IPv6 specification mandates support for Internet Protocol Security (IPsec) as a fundamental interoperability requirement.It will also expand the capabilities of the Internet and enable a variety of valuable and exciting scenarios, including peer-to-peer and mobile apps.
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. The 128-bit IPv6 address can be abbreviated with the following rules:
- Rule one: Leading zeroes within a 16-bit value may be omitted. For example, the address
fe80:0000:0000:0000:0202:b3ff:fe1e:8329may be written asfe80:0:0:0:202:b3ff:fe1e:8329 - Rule two: A single occurrence of consecutive groups of zeroes within an address may be replaced by a double colon. For example,
fe80:0:0:0:202:b3ff:fe1e:8329becomesfe80::202:b3ff:fe1e:8329
(Source: Wikipedia)
