Differences between IPv4 and IPv6

Great expansion of network address space

IPv4 The number of addresses is 32 position , That is, at most 2 Of 32 The power computer can be connected to internet On .IPv6 It's the next version of the Internet Protocol . With the rapid development of the Internet ,IPv4 The defined finite space will be exhausted .IPv6 The length of the address in is 128, That is to say 2 Of 128 Power -1 An address

The network address representation is different

stay IPv4 in , There are two formats, binary and dotted decimal , In fact, the dotted decimal system is generally used in daily life . because IPv6 Overlong 128bit Address , Whether binary , Or dot decimal , Can't express effectively and concisely , So the colon hexadecimal is quoted to represent IPv6 Address .

The classification of network addresses is different

about ipv4 Come on ,IP Address is divided into A,B,C,D,E Five category , There are unicast addresses , Multicast address and broadcast address . And in the IPv6 It's cancelled Ipv4 Broadcast address in , The broadcast has been for IPv4 The network brings problems , It may have a disastrous impact on network performance . meanwhile IPv6 Also added anycast address , This plays an important role in routing optimization .

The improved IP multicast

IPv6 Multicast has been improved , It is embodied in the following three aspects ：

1. The necessity of multicast is emphasized
2. Improvement of multicast address
3. take IP Multicast is divided into intra domain multicast and inter domain multicast , Improved its manageability .

Different header formats

IPv6 Basic header format ratio IPv4 The header is much simpler .IPv4 There is 10 A fixed length field ,2 Address spaces and several options ,IPv6 There are only 6 Multiple domains and 2 Address space . The simplification of the header makes IP Some ways of working have changed ： Because all headers have the same length , Therefore, the header length field is no longer required ;IPv6 Segmentation in can only be done by the source node , The intermediate router no longer performs any segmentation , Reduce the workload of the intermediate router ; Get rid of IP Header checksum does not affect reliability , Mainly because the header checksum will be agreed by higher layer TCP/UDP be responsible for .