Moving from IPv4 to IPv6

IP (Internet Protocol) is the protocol that governs communications on the Internet. In order to connect and communicate, each device (computer, smartphone, tablet, and more.) needs a unique identifier. This identifier is called the IP Address. As of date, we have two versions of IP: IPv4 and IPv6.

The founders of the Internet decided to use IPv4 addresses to identify devices on the Internet. These IPv4 addresses are coded on 32 bits, which translates to 4.2 billion available addresses. With more and more devices getting online every day, this number is unable to ensure scalability and growth of the Internet. The IPv6 address space was then created by the IETF engineers to solve the problem of IPv4 address depletion.

IPv6 is coded on 128 bits and has 2^128 =

340,282,366,920,938,463,463,374,607,431,768,211,456

• IPv4 is 32-Bit IP address whereas IPv6 is a 128-Bit IP address. 

• IPv4 is written in decimal dotted format (192.168.10.1), whereas IPv6 is represented in hexadecimal characters separated by colons (:) (2001:db8:c001:aba::dead). 

• IPv6 packet base header has been simplified and now has 8 fields in contrast to IPv4 packet base header with 14 fields.

• In IPv6 there are no more broadcast communications. 

• Functions like ARP in IPv4 are now taken care of in IPv6 with a new protocol called NDP(Neighbor Discovery Protocol). This NDP relies on ICMPv6(ICMP for IPv6 with additional messages) messages. 

• In IPv4 Packet size of 576 bytes required and fragmentation optional while in IPv6 1208 bytes required without fragmentation. 

• Quality of service is better-taken care of in IPv6 with fields in the base header like “traffic class” and “flow label”.

• With Link-local addresses and the Stateless Address Autoconfiguration (SLAAC) IPv6 devices are “almost” plug-n-play.