Computer technology greatly facilitates the life of mankind, and since we are talking about local networks, the specific application of a computer network is diverse, but the simplification of familiar tasks is at the heart of everything. Local networks facilitate many tasks in terms of data transfer within the company or in a private home network. We’ll talk about this today.
LAN Benefits
So you wanted to transfer the film to the memory card of a tablet or smartphone, and get up lazy, but if you have created a home local network, then you can easily use a video player that supports streaming via a local network, for example, VLC Media Player.
VLC Media Player you just need to start, select the "Stream" mode and calmly watch a movie, without getting up from the couch, on another device, or through shared access to a folder, then you will need to select the local network in the program and the file that should be opened.
Or you are a business owner, and all employees need to work with high productivity. You can constantly let them catch up, but there will be more sense from highly qualified specialists if you provide them with modern technology. Suppose you have a private documentary company, every time any employee will get tired of going back and forth, and productivity will drop. A local network will come to the rescue, with its help you can get rid of the "time eater" in the form of eternal running around between tables in search of the necessary information.
This is a small number of examples of the use of local area networks.
Let's analyze the following concepts: local network, types of local networks, their advantages and disadvantages.
The local network
A computer network, also known as a computing or local area network, is a system for exchanging data between electronic devices, provided by transmission media. The latter can serve as optical fiber, radio waves, etc. It provides data transfer of up to 10-15 kilometers between subscribers. Especially useful when located inside one large building or in several adjacent buildings.
Main advantages
The advantages of technology can be considered:
- Sharing resources - the rational use of devices within the network.
- Data distribution - access files from other devices. Organization of work and general access to the working document and other files.
- Separation of applications installed on computers - the use of programs installed on neighboring computers.
Types of LANs
There are two models of local area networks:
- Peer-to-peer network.
- Client-server network.
We begin by explaining the first term.
In peer-to-peer, all information is distributed between devices. Any user can change file permissions. The workstations are the computers themselves.
Provides full access to any network user to any resources and device files.
Benefits:
- This type is easy to implement and affordable on a small budget.
- Connect up to 20 devices (possibly more).
Disadvantages:
- Many devices - low performance (observed with old hardware and software).
- Lack of a single information base.
- Low security.
- The dependence of information on the state of the computer, that is, if the device is turned off, then the information will not be available.
Client-server networks have only one host computer — the server. It stores information and processes it.
Server Types:
- Universal server - for simple tasks, data processing in a local network.
- Database server - processing requests sent to the database.
- Proxy server - connecting a local area network to the Internet (VPN).
- File server - resource allocation and file access.
- Application Server - execution of application processes.
- Mail server - replies to requests sent by e-mail.
Benefits:
- good performance;
- single database of information;
- advanced security system.
Disadvantages:
- cost;
- need qualified personnel for service.
LAN creation
Hardware. The whole system rests on the transmission of data so that they can be sent, the following devices are needed:
Network adapter - a card for transmitting and receiving information from the network. Computers can be connected using cables of various types (fiber optic, twisted pair, coaxial).
A cable is the basis of a communication channel — the physical medium of data transmission. Particular attention should be paid to bandwidth (bit / s, kilobits / s, megabits / s, etc.). As an example, an RJ45 cable.
Also used:
- A hub is a device for transmitting a signal from one device to another. An average of 8 to 30 connectors (ports) for connecting a computer or other hub. Each port is for a separate device. Due to them, the entire network works.
- Wi-Fi router - a device for wireless data transmission, which allows you to connect up to 10 devices. Suitable for home network or computer club. You can install many routers with a router, then the network will be wireless, and the number of devices will be limited only by location and budget. Plus, you can connect external memory to the router.
Software. In addition to hardware, you need special software and set up a computer or other device to work inside the network:
- System with LAN support.
- Configuring individual folders and data for external access.
All modern, and quite old systems, such as Windows XP, support the creation and access to files on the local network. So the main search for programs to access the network comes down to individual devices, such as smartphones, tablets (not Windows), devices based on the Linux kernel, etc.
LAN Topologies
There are such varieties:
- Common Bus (bus).
- "Ring" (ring).
- "Star" (star).
- The physical star and logical token ring.
Topology "common bus".
It uses a single channel for data transmission via cable (coaxial), termination resistors (terminators) are installed at the ends. Connection via a T-connector. Information goes to all nodes, but is accepted only by the specific.
Benefits:
- Host failure will not affect the operation of the entire network.
- Easy setup.
- Resistance to malfunction of individual nodes.
Disadvantages:
- A cable break affects the operation of the entire network.
- Limit on cable length and number of workstations.
- Difficult finding of a defect in a joint.
Ring topology.
All nodes are connected in an inextricable ring, which provides information transfer. Transmission goes through each device on the network, from one point to another. Data moves in one direction.
The advantage is the ease of creation and configuration. Among the shortcomings can be called the fact that if the communication gap is damaged or the computer fails, the entire network malfunctions.
Local Area Network Topology.
Each pc or server is individually cabled to a hub or hub. The latter provides a parallel connection.
Benefits:
- Easy connection of new devices.
- Centralized management.
- Resistance to malfunctions of individual devices on the network.
Disadvantages:
- The failure of the repeater (hub) adversely affects the operation of the entire network.
- Need a lot of cable.
Token Ring Topology.
Based on ring topology. The best topology, as it offers that access is distributed evenly across all workstations and provides high reliability due to the resistance to breaks of individual stations. However, a very expensive option.
The classification of local networks is divided into simply local and local extended networks.
Scopes of local area networks
The following applications of technology are known:
- Creation of personal local area networks.
- Game clubs and game on a local network with friends.
- Automation of management activities, organization of "electronic offices".
- Automation of production.
- Learning Automation.
Threats
Many types of LANs can be hacked.
Since all computers are connected to the same network with shared access to each other’s files, it’s likely that all this will allow any hacker to inject a virus, a trojan into the network, which will spread to all computers and devices on the network (almost all), where there are problems with security.
The same maintenance specialists can pose a threat to the company, because it doesn’t really affect the network, especially if the server-client system is not so dangerous for a peer-to-peer network.
And you can do a lot:
- To steal all data, especially if they are not protected by anything and are in the access of the local network.
- Introduce a spy so that it investigates the actions of users.
- Where there are working computers, there are home computers. With a flick of the wrist, all malicious code will be redirected to the home computer if antivirus is not installed on it.
- You can stop the network activity itself by causing a reboot.
- And much more.
Therefore, you need to worry about the security of the entire network.
LAN protection
It is necessary to use anti-virus solutions from various companies, anti-spyware programs, monitor network activity, conduct encryption, apply the creation of DMZ - when the network fragment is not completely trusted, IDS - intrusion detection system, NAT - technology for translating one or more addresses to other addresses, firewall or Firewall, changing the file system to NTFS (for professionals), installing the latest system updates, not providing full access to employees on their computers, i.e. their rights and administrative rights. Peer-to-peer local area network is usually not needed by anyone, since they are used in schools and institutes, and there is nothing special to get there.