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This paper is participating in theNetwork protocols must be known and must be known”Essay campaign

In the last section, we talked about the hierarchical structure of computer networks. Today, we are going to talk about some terms and concepts in computer networks, which will make it easier for you to read some professional books and lay some foundation for the following content.

What are the core and the edge

Computer networks can be divided into core and edge parts:

The edge usually refers to the terminal devices we use (usually called hosts, but also divided into clients and servers), which are used to run various network applications.

The core provides services for the edge, including connectivity and data exchange, and is composed of a network and its routers.

The edge part uses the services provided by the core part to enable many hosts to communicate with each other and exchange or share information.

What is network protocol?

We hear a lot about TCP, HTTP, and so on. First of all, let’s figure out what a protocol is and why it exists.

The interpretation of network protocol official points is the set of rules, standards or conventions established for data exchange in computer networks. In simple terms, we know that computer network as a network, there are a lot of nodes, nodes need to exchange data information, so some rules (protocol) to agree how to exchange information (data).

Network protocol is composed of three important parts, they are grammar, semantics, timing, the first two are easier to understand, because we in real life, human information exchange language needs grammar and semantics. Semantics indicate what to do, syntax indicates how to do it, and timing indicates the order in which to do it. Timing is a detailed description of the order and time in which events are implemented, including when and at what rate data should be sent.

What are IP addresses and MAC addresses

With the protocol, the nodes in the computer network can communicate, but how to distinguish the different nodes, here is the need to use the address.

In computer networks, we often see the concept of two types of address, an IP address and a MAC address

According to the network reference model we talked about in the last section, seven layers, right? Five layer? Four layers? In juejin.cn’s blog, IP addresses belong to the IP protocol, which is the network layer, and MAC addresses belong to the data link layer

The LENGTH of a MAC address is 48 bits (6 bytes), and it is usually represented as 12 hexadecimal digits. Two hexadecimal digits are separated by colons, for example, 00:50:29:55:8h :1E is a MAC address.

IP addresses are 32 bits, consisting of four eight-octet groups separated by dots. For example, 192.168.0.1 is an IP address, which is written in the dotted decimal notation format.

The MAC address is the physical address of the NIC based on the manufacturer, and the IP address is the communication address of the NIC based on the network topology. For example, a MAC address is an id that comes with it as soon as it’s made. It’s the birth id number of each of us. And the IP address, we can think of it as our real address. Therefore, THE IP address has the location function.

This is just a primer on some of these concepts, and we’ll talk about them later when we talk about the network layer and the data link layer.

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