What stages did the Internet go through? What are your main characteristics at these stages?

The development of Internet can be roughly divided into three stages:

The first stage: from a single network device to the Internet, the initial formation of TCP/IP protocol;

The second stage: build three layers of internet, which are divided into backbone network, local area network and campus network;

The third stage: the Internet with multi-level ISP structure is formed, and ISP appears for the first time.

disadvantaged

First, there is no overall planning and design, the network topology is unclear, and it lacks fault tolerance and reliability.

Second, in the commercial field, security is another big factor that bothers users.

Third, the Internet is a network without a center.