Original address: www.sohu.com/a/158380153…

IP

As an important bridge of the Internet, IP is a protocol designed for computer networks to communicate with each other. In the Internet, it is a set of rules that can make all computer networks connected to the Internet communicate with each other. It specifies the rules that computers should follow when communicating on the Internet.

Any computer system manufactured by any manufacturer can be connected to the Internet as long as it complies with the IP protocol. Thanks to THE IP protocol, the Internet has rapidly grown into the world’s largest open computer communication network. Therefore, IP protocol can also be called “Internet protocol”.

IP addresses are used to number computers on the Internet. What you see on a daily basis is that every NETWORKED PC needs an IP address in order to communicate properly. We can compare “personal computer” to “a telephone”, so “IP address” is equivalent to “telephone number”, and the Internet router, is equivalent to the telecommunications office “programmed switch”.

Common IP addresses are classified into IPv4 and IPv6. Currently, IPv4 is mainly used. IPv4 consists of four digits, each consisting of 0 to 255 digits. The biggest problem of IPv4 is the limited network address resources, which seriously restricts the application and development of the Internet. Therefore, there is the emergence of IPv6. The use of IPv6 can not only solve the problem of the number of network address resources, but also solve the obstacles for a variety of access devices to connect to the Internet. The length of an IPv6 address is 128 BYTES, four times that of an IPv4 address.

Differences between IPv4 and IPv6

IPv4

The current protocol family used by the global Internet is TCP/IP protocol family. IP is the network layer protocol of the TCP/IP protocol family and is the core protocol of the TCP/IP protocol family. The current VERSION of the IP protocol, version 4(IPv4 for short), has been in use for more than 30 years.

IPv4 has 32 address bits, meaning that up to 2 ^ 32 computers can be connected to the Internet.

In recent ten years, due to the rapid development of the Internet, the demand for IP address is increasing, which makes the IP address issue more and more strict. According to various data, the global IPv4 address may be issued from 2005 to 2008.

IPv6

IPv6 is the next version of the Internet protocol, also can be said to be the protocol of the next generation of the Internet, it was originally proposed because with the rapid development of the Internet, IPv4 defined limited address space will be exhausted, the lack of address space will hamper the further development of the Internet. In order to expand the address space, it is proposed to redefine the address space through IPv6.

IPv6 uses a 128-bit address length and can provide addresses almost without restriction. Using conservative estimates of the actual addresses that IPv6 can allocate, there are still more than 1,000 addresses per square metre of the entire planet.

In the design process of IPv6, besides solving the problem of address shortage once and for all, other problems that cannot be solved in IPv4 are also considered, including end-to-end IP connection, quality of service (QoS), security, multicast, mobility, plug and play, etc.

Advantages of IPv6 over IPv4

  • Larger address space :IPv4 specifies that the length of an IP address is 32, that is, there are 2^32-1 IP addresses. In IPv6, the length of an IP address is 128, that is, there are 2^128-1 IP addresses.

  • Smaller routing table :IPv6 address assignment follows the Aggregation principle from the very beginning, which enables a router to represent a subnet with an Entry in the routing table, greatly reducing the length of the routing table in the router and improving the speed at which the router forwards packets.

  • Enhanced multicast support and convection support: this makes multimedia applications on the network have a great opportunity to develop, providing a good network platform for quality of service (QoS) control.

  • Added support for automatic configuration: this is an improvement and extension of DHCP protocol, making network (especially LAN) management more convenient and fast.

  • Higher security: On an IPv6 network, users can encrypt data at the network layer and verify IP packets, which greatly enhances network security

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