internet can now be done with much flexibility. It has also eliminated the use of NAT, which is now widely adopted in an attempt to save IPv4 from address space shortage (Ali, 2012). In addition to its larger address size, IPv6 also has other features that offer many advantages over IPv4. These are:Quality of Service mechanisms: Although there is type of service field included inthe IPv4 header for traffic classification, traffics generated by different applications in current networks are treated the same way.
This treatment is often called best–effort service. Best–effort service does not favor network applications whose transmissions are time bound. They are rather delayed leading to packet loss or jitter that reduces their quality (Bouras et al, 2006).
The header of IPv6 is designed to include QoS mechanisms. Inside the header of IPv6 are the traffic class and the flow label fields that are intended for traffic classification in order to provide quality of service. With these two fields, nodes in IPv6 can distinguish certain packets so that routers can take special care of those packets (Cooper et al, 2005).
• Stateless auto configuration: Stateless auto configuration is an essential feature built into the next–generation internet protocol. Every device connected in an IP based network must be assigned an IP address. In IPv4, the task of assigning IP address is only done either manually or using a stateful protocol like the DHCP, which requires a server to store configuration information requested by a host. IPv6 also supports stateful auto configuration via the use of DHCPv6.
In addition to this, IPv6 provides a stateless auto configuration allowing each network device to automatically acquire its IP address without the help of a server (Caicedo et al, 2009).• Mobile IP (MIP): The main purpose of this feature is to enable every mobile device to maintain its IP address while it moves from one network segment to another (Davies, 2003). Thus with the mobile IP, a mobile device can change its location and 3 address without losing the connection through which it is communicating (Durgadi et al, 2010).• Simplified Header: The header of IPv6 is simplified in contrast to the IPv4 header.The length of the IPv4 header is 20 bytes.
However, its optional fields are variable inlength. This adds to the actual size of the IPv4 header. The size of the IPv6 header isfixed. It is only 40 bytes. Also in IPv6, some fields used in IPv4 are removed.