In the future, not only personal or network computers will need an IP address,
but also more electronic home devices will require their own unique IP
addresses. The large address space of IPv6 enables every device to obtain its
own unique Internet address. That will enable us, for example, to control the
security camera from anywhere or to turn on the air-conditioner of the house
while we are sitting in the office.
There are three types of address in IPv6: anycast, unicast and multicast [6]. In
IPv4 there are: unicast, broadcast, and multicast address.
The anycast address is an additional address to IPv6, for sending the packet to
the nearest node in the group, according to the routing protocol measure of
distance. It provides for applications such as file and print servers, DHCP,
etc. The unicast address is used to identify a single interface.
The broadcast address is undefined in IPv6, but it is one form of multicast in
IPv6.
The IPv4 address is written by dotted-decimal notation, e.g. 121.2.8.12, but
IPv6 is written in hexadecimal and consists of 8 groups, containing 4
hexadecimal digits or 8 groups of 16 bits each [6], e.g. FABC:
AC77:7834:2222:FACB:AB98:5432:4567.
The IPv6 header is a static header of 40 bytes in length, and has only 8 fields.
Option information is carried by the extension header, which is placed after the
IPv6 header. If there is no option information, there is no need for extension
header, and the packet size is thus reduced.
As shown in figure 1, the basic length of the IPv4 header comprises a minimum of
20 bytes (without option fields). The maximum total length of the IPv4 header is
60 bytes (with option fields), and it uses 13 fields to identify various control
settings.
Green: Field name kept from IPv4 to Ipv6
Blue: Field not kept in IPv6
Red: Name and position changed in IPv6
Black: New field in IPv6
Fig. 1: IPv4 Header
Fig. 2: IPv6 header
