Overview of computer networks and Internet connections

Overview of computer networks and Internet connections

I. Computer Networks and Internet connections

1. Computer Network (hereinafter referred to as a network): it is composed of several nodes (also known as nodes) and links connecting these nodes. Nodes can be routers, hubs, switches, etc.

2. Internet: networks are connected by routers to form a larger computer network, that is, the Internet.

Note: Generally, one cloud is used to represent a network. There are two scenarios when you use Alibaba Cloud to represent the network. One is to include the network and the computer connected to the network. The other is that there are only routers and links, and computers are connected to the cloud. Computers connected to the outside of the cloud are often called hosts.

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Ii. Internet

1. Internet (Internet) Definition: it refers to the world's largest and most open, and is composed of many networks connected to each other, it uses TCP/IP protocol family as the communication rules.

Note: the Internet and Internet are different. An Internet connection is a computer network connected by multiple computer networks. The communication protocols between these networks can be selected at will, and you do not have to use the TCP/IP protocol. (Main differences)

2. Multi-layer ISP-structured Internet:

Host A communicates many different levels of ISPS with the Host:

ISP: Internet Service Provider (Internet Service Provider ). Such as China Telecom, China Mobile, and China Unicom. Apply for multiple IP addresses from the Internet management organization, and have communication lines, routers, and other connected devices.

Internet access means access to the Internet through an isp ip address.

IXP: Internet exchange point. The role is to allow two networks to directly connect and exchange groups, instead of forwarding groups through the third network.

3. Standardized formulation of the Internet: recommended standards to Internet standards. These documents are called RFC (request comment) documents.