1. What is a network?
Network devices around you
In fact, the network exists in every corner of our daily life! Your computer, printer, mobile phone, and even TV are all network devices. Usually, we need to connect these devices through the network, so that we can realize the transmission and sharing of data, making our work and life more convenient.
Collaborative work
If we don't have problems with our connection, we can send instructions to the printer from our computer and ask it to print the material for us, or store it on our local server, or publish an article or video to the Internet.
But the problem is that although we are usually doing these daily operations, we are not aware of the existence of the network, or we are not very aware of the internal workflow and details. The reason why we can browse videos, download materials, send emails or video chat with friends through the Internet is actually the result of tacit cooperation between network devices.
1. Switches
So, what do we rely on to connect these network devices? "Switches" also need to be matched with device cables to achieve interconnection between devices.
switchboard
For example, most of the computers in the company office or school classroom can be connected to a network cable interface on the wall or other locations using a network cable, and the network cable interface is connected to the patch panel through a cable, which is generally placed in a separate room or cabinet, and then only needs to connect the patch panel to the "switch" to achieve a basic network connection.
For the "switch", ordinary home users may rarely hear of it, that is because, we usually connect the cable directly to the optical modem or router, after all, we have relatively few network devices in our home, but for a business or school organization, they have a lot of computers, and the management of the cable is also complicated, the switch can solve this problem very well. (We will explain "Switches" in more detail in the following chapters.)
The device is directly connected to the switch
Of course, if we don't have a lot of equipment, we can also connect the cables directly to the switch, and the specific situation depends on the number of devices and cables we have.
2. Wireless connection
The reality is that in addition to desktops, the most commonly used mobile devices are mobile devices, mobile phones, mobile laptops, and tablets, most of which do not require cables, and can also achieve network connection, which is achieved through the so-called "wireless connection technology (Wi-Fi)". With it, we will be able to surf the Internet wirelessly within the range of Wi-Fi coverage.
Wireless connection
If the wireless device is also connected to the switch, we can share the content of the wired and wireless devices in a local network, for example, the information on the mobile phone is transmitted to the printer for data printing, and it should be noted that the data transfer speed will be different between the wireless connection and the wired connection.
The wireless device is connected to a local network
My use of mobile devices at work is like this: when I'm sitting at my desk, I'm going to use a wired connection, because it's faster, but if I'm in a meeting, I'll unplug my computer, go to the conference room with my naked laptop, and connect to the Wi-Fi.
Real office scenes
3. Network Protocols
Either way, the ultimate goal is to send information from one device to another, so the sender and receiver must understand each other, which requires them to speak the same language on the network. We don't need to worry about that, though, because devices basically know how to organize, process, and send data. The bottom line is that they all follow the same set of rules, which we call "protocols."
Network protocols
Agreements are "communication rules for both parties", which means that if both parties want to cooperate tacitly, they must follow these agreements, and because of this, if there is a problem with one party, we can quickly and accurately locate the problem.
In computer networks, engineers who design network software and hardware will strictly follow this set of "protocols" to ensure that they are unimpeded in the network! You may have heard of protocols such as "Ethernet", you may have heard of "TCP (for sending and receiving data)" protocol, or "HTTP (for accessing the network)" protocol, or "SMTP (for sending and receiving email)" protocols, which will be explained in more detail in the following chapters...... Regardless of the protocol, the ultimate purpose is to complete data exchange.
Often, we use a combination of several protocols to accomplish a single task.
4. Summary
- The role of the network is to connect devices together, so that devices can share resources, information exchange and other functions
- Network devices need to speak a common language and follow the same rules, which we call "protocols"
- A protocol is a set of instructions about how a device should process information
5. Quiz
- What are the two ways for a computer to connect to a network?
- What devices are typically used for unified connectivity between multiple network devices?
- What protocols apply when you want to interact with one computer over another?
2. Network type
In this section, we'll learn the following:
- What are the nodes in the network?
- What types of networks can we build depending on the network nodes?
- In our daily life, what are the practical application scenarios of different network types?
1. Network nodes
A device that is connected to a network and is able to send, receive, or forward information over a communication channel can be called a "network node". For example, switches, routers, computers, printers, mobile phones, etc., all belong to a node in the network.
2.Soho Network
A small network with only a few nodes can be called a "SOHO network", and a network built in a small office or home office is a "SOHO network". It is usually a small network environment with only a few computers, printers, a few mobile phones and tablets.
switchboard
It's worth mentioning that people often refer to "switches" as "central hubs", and it's true that "switches do look like hubs", but here you should remember that switches and hubs are completely different things! Hubs are really old technology, and we basically don't see them now. The switch is a very commonly used network device nowadays, so it must be clearly distinguished.
Router (integrated switch and router functions)
In SOHO network, we usually use routers to complete network connection, because most modern routers integrate the functions of routers and switches, but usually because there are few interfaces in routers, we can only access a small number of node devices to achieve network sharing.
3. Local Area Network (LAN)
Enterprise networking
For example, a local banking enterprise, their network equipment may be spread over several floors, or even across multiple buildings, at this time, the network of network equipment of this size connected together is called "local area network (LAN)".
LAN - 1
In fact, the "SOHO network" is also a local area network, but the "SOHO network" connects a small number of devices. In an enterprise network, we will need to use multiple switches to link routers, which can be understood as a larger network structure that connects multiple "SOHO networks" together.
LAN - 2
4. Wide Area Network (WAN)
Although "LAN technology" can enable network nodes in a large area to interconnect and share information, what if the area expands and spans cities and regions? For example, if a cross-regional banking company does not usually have office buildings in only one region, but may have its own office buildings in each region of the country, the banking network becomes very large, and even if the distance is far away, the banking company wants to connect all these networks together, so we need to use a new network construction technology called "wide area network (WAN)".
WAN
For example, if we have a multinational company with offices in Sydney and Melbourne, and we share data in our Sydney office, and we want to access that data in our Melbourne office, we need to contact a service provider to help us interact with the data over a distance.
The Sydney office shares data to the Melbourne office
5. Summary
- SOHO Networking: Usually suitable for homes or small offices
- LAN: A network architecture suitable for multiple floors
- Metro MAN: suitable for network architecture within 10~100km
- Wide Area Network (WAN): It is suitable for large networks of more than 100 km and usually spans countries and regions
6. Quiz
- You work in a company where the finance department, the engineering department, and the management department each have a local area network LAN, and the local area networks of the three departments are all connected together, is this network still a local area network LAN?
- In addition to the head office, the company has six branches, so what kind of network does this company belong to?
epilogue
If you think the article is great, you can forward and comment on the article, if there is a problem with the article, please leave a message or private message to tell me, I will adjust the content at the first time, which will help everyone who wants to learn the basics of the network, thank you!
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From: Minority, Author: Fang Daluo Link: https://sspai.com/post/64634