As an important bridge of Internet, IP is a protocol designed for computer networks to communicate with each other. It is precisely because of the IP protocol that the Internet has rapidly developed into the largest and most open computer communication network in the world. What's the difference between IPv4 and IPv6? Not really. Next, I will introduce the differences between IPv4 and IPv6 in detail.

The difference between IPV4 and IPV6: First, the expansion of routing and addressing capabilities.

IPv6 increases the IP address from 32 bits to 128 bits, which can support a larger address space. It is estimated that there are 4 * 10 18 IPv6 addresses per square meter on the earth's surface, so IP addresses will not run out in the foreseeable future.

IPv6 addresses are coded in a hierarchical structure similar to CIDR, just like telephone numbers. Simplify wiring and speed up wiring. A "range" domain is added to the multicast address, so that multicast is not limited to subnets, but can span different subnets and different LANs.

Second, the simplification of the title format

Some redundant fields in IPv 4 header format are either discarded or listed as extended headers, thus reducing the overhead of packet processing and header bandwidth. Although the address of IPv6 is four times that of IPv4. But the header is only twice as big.

Third, increase support for options.

The IPv6 option is not placed in the header, but in a separate extension header. If no router is specified, the processing extension header will not be opened, which will greatly change the routing performance. IPv6 relaxes the strict requirements for optional length (the maximum optional length of IPv4 is 40 bytes), and new options can be introduced at any time as needed. Option provides many new functions of IPV6, such as supporting IP layer security (IPSEC), jumbogram and Mobile-IP.

Fourth, the function of QoS.

Internet can not only provide all kinds of information, shorten people's distance, but also provide online entertainment. Nowadays, online VOD is being heated by merchants, but most of it just stays at the level of quasi-VOD and can only be realized on LAN. Online VOD is not ideal. The problem is that although there is a service type field in the header of IPv4, it is actually ignored in the current router implementation.

In the header of IPv6, there are two corresponding priority and flow identification fields, which allow datagrams to be designated as part of the information flow and can control the flow of these datagrams. For real-time communication, even if all packets are lost, the priority is the highest, while a news packet is delayed for a few seconds without feeling, so the priority is low. IPv6 stipulates that these two fields must be implemented by each IPv6 node.

Verb (abbreviation for verb) authentication and confidentiality

Authentication, data consistency and confidentiality are added in IPv6.

Sixth, the security mechanism IPSec is necessary.

IPv4 is optional or requires paid support.

Seven, strengthen the support for mobile devices.

The design concept of IPv6 is to support mobile devices and allow mobile terminals to keep the same IP address when switching access points.

Eight, support stateless automatic address configuration

IPv6 can complete address configuration and broadcast address prefix without DNS server, and each host can generate aggregated global unicast address according to its own MAC address and received address prefix. This also facilitates the host in a certain area to change the IP address prefix at the same time.