Basic knowledge and architecture of computer network

Modern society, the network has become the same as water, electricity as our indispensable daily needs, can say that the network everywhere. As a user, you only need to learn how to use the network, and as a computer professional students, a programmer is necessary to understand the principles.

Therefore, this chapter will mainly introduce some basic definitions of computer networks, network architecture, etc., aimed at learning the basic concept of computer networks, for the next network programming to lay a good foundation.

Before the sophomore in the computer network, but too long a lot has been forgotten, so this blog is my own knowledge of a comb, the main reference book is Shehiren's "computer network." Basic Knowledge

The most important function that the computer network provides to the user is two: connectivity: the so-called connectivity refers to the network allows users to exchange information, as if the user's computer is connected to each other sharing: resources can be shared, user-friendly network can be seen as a number of nodes and links to link these nodes are composed of , where nodes can be computers, hubs, routers, switches, and so on.

The Internet links a lot of computers, and the Internet links up many networks. The internet itself is complex, but it is divided into the following two chunks from the way it works:

1. About the marginal part:

The Edge section utilizes the services provided by the core to enable many hosts (end systems) to communicate, exchange, or share information. Deeper understanding, host A and Host B communication, is actually a process of host A and Host B of a process communication .

The communication between the end systems can generally be divided into two categories, client-server (CS model), peer-to-peer. 2. With regard to the core segment:

The core is complex because it provides services to a large number of hosts on the edge, allowing any host to communicate to other hosts.

Among them, the key role is the router, it is also a dedicated computer, mainly to implement packet switching, that is, forwarding received packets.

advantages and disadvantages of grouping:

Performance Index of computer network rate bandwidth throughput delay round trip time

Concrete visible Shehiren "Computer Network" sixth edition p19 computer network Architecture

There are two main models, one is OSI seven layer model, and one TCP/IP four layer model.

This is in the "Computer Network" book A paragraph of text and pictures, to illustrate the network architecture, in fact, we generally focus on the TCP/IP layer four protocol.

about why layering. The book also gives the benefits of layering: