The concept of IPv6
IPv6 (Internet Protocol version 6 Internet Protocol Version 6), is the IETF next-generation IP protocol used to replace the current version of the IP protocol (IPv4) in the (Internet Engineering Task Force, Internet Engineering Task Force) designs.
IPv6 network was originally proposed to expand the IP address space. In fact, IPv4 has great limitations in addition to the address space, become simmer major obstacle to development of the Internet outside, IPv4. Transmission speed. Security, mobility and support for multicast and so there are limitations in the quality of service, these same limitations hinder the further development of the Internet. Many services and applications on the Internet is difficult to carry out. Therefore, the IPv6 design process, in addition to once and for all solve the address shortage, it also takes into account the poor to solve other problems in the ipv4. IPv6 in relation to IPv4 main advantages are: expanded address space, increasing the overall throughput of the network, service quality has been greatly improved, with better security guarantee.
IPv6 features
◆ IPV6 address length is 128, the address space is increased 96-fold power of 2;
◆ flexible IP packet header format. Using a series of fixed format option extension header field IPV4 substituted in a variable length. IPV6 mode appears in the Options section also changed, so that the router can simply pass by without doing any processing option to speed up message processing speed;
◆ IPV6 simplified packet header format, the field only eight, accelerate packet forwarding throughput is improved;
◆ improve security. Authentication and privacy are key features of IPV6;
◆ support more service types;
◆ allow agreement to continue to evolve, adding new features to make it future-proof technology.
IPv6 datagram
IPv6 datagram format is as follows:
The IPv6 header length becomes a fixed 40 bytes, referred to as a basic header (baseheader). The abolition of unnecessary functions, reducing the number of field header to only eight. Cancel the test and field header, accelerate the speed of the router that handles the datagram. Behind the header portion substantially allows zero or more extension header. All extension headers and the payload data together called a datagram (payload), or payload.
The difference between IPv6 and IPv4 datagrams
The original function of IPv6 IPv4 header are placed in the options extension header, and the header extension main left ends of the source station and destination path to the processing station. Datagram way through routers do not handle these extensions header (header only one exception, namely by-hop options extension header). This greatly improves the processing efficiency of the router. Defined in [RFC 2460] Six extension header: hop options, routing, fragmentation, authentication, and Encapsulating Security Payload destination options.
