Computer networks and their classification presentation. Presentation on the topic of classification of computer networks
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Computer networks Classification of the Kyrgyz Republic PTUZ "FPTSU" Creative work of student group 21/22 Velichkovskaya E.K. Feodosia 2009Slide 2
Computer network (computer network, data network) - a communication system between two or more computers and/or computer equipment (servers, routers and other equipment)
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A personal network is a network built “around” a person. These networks are designed to unite all the user’s personal electronic devices: Telephone Pocket personal computer Smartphones Laptops Headsets, etc.
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Local area network (LAN) A network that usually covers a relatively small area or a small group of buildings Home Office Enterprise As a rule, such networks connect computers located at distances (about 50–1000 meters) within one or more nearby buildings.
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City computer network Connects computers within the city. City network is the provider's core network, points connected by high-speed channels. Distance - from 1 to 10 km.
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Regional network is an association of computers and local networks to solve common problems on a regional scale. Located within a certain territorial region.
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A global network is an association of computers and local networks located at a remote distance for the common use of the world's information resources. Iain Foster
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Departmental network Belongs to one organization and is located on its territory: ATM network Railway ticket offices Theater ticket offices, etc.
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Twisted pair networks Twisted pair is a type of communication cable, consisting of one or more pairs of insulated conductors, twisted together (with a small number of turns per unit length), covered with a plastic sheath. Currently, due to its low cost and ease of installation, it is the most common solution for building local networks.
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Coaxial networks Coaxial cable is a cable in which the internal wire is surrounded by a second shielding wire to reduce radio interference. The main purpose of coaxial cable is signal transmission in various fields of technology
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Fiber Optic Networks Optical fiber is a glass or plastic strand used to carry light within itself through total internal reflection. Optical fiber can be used as a means for long-distance communication and building a computer network.
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Classified: Wireless is a technology that allows you to create computer networks that fully comply with the standards for conventional wired networks (for example, Ethernet), without the use of cable wiring.
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Transmission over radio channels Communication over a radio channel is used to build highways (radio relay lines), to create local networks, and to connect remote subscribers to networks and highways of various types. A wireless network works where a cable network does not.
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In the infrared range It has a wide range of frequencies. Transmission is carried out with a narrow beam in the complete absence of lateral radiation. The transmitter is a semiconductor emitting diode. A highly sensitive photodiode is used as a receiver. High communication confidentiality.
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Information transfer rate - the speed of data transmission, expressed in the number of bits, symbols or blocks transmitted per unit of time.
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Based on the speed of information transfer, computer networks are divided into low-, medium- and high-speed. low-speed (up to 10 Mbit/s), medium-speed (up to 100 Mbit/s), high-speed (over 100 Mbit/s); Baud A unit of signal transmission speed measured in the number of discrete transitions or events per second. If each event represents one bit, a baud is equivalent to bits/sec (this is often not the case in real communications).
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A linear network is a Point-to-Point network. With this organization, the network consists of two computers directly connected to each other. The advantage of such a network organization is its simplicity and relative cheapness, but the disadvantage is that only two computers can be connected in this way.
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A common bus network consists of several computers, each of which is connected to a common data transfer bus for the network. A coaxial cable can act as a bus. The main disadvantage of this organization is that if the bus breaks, all network nodes lose communication. If it is necessary to connect another node to the network, then during installation work the connection will also be lost
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Ring network A network consists of several computers, each of which is connected to a cable closed in a ring. The signal is transmitted along the ring in one direction and passes from computer to computer. In this case, the computer, having received a signal from a neighboring machine, amplifies it and transmits it further along the ring. This happens until the signal reaches the computer to which it is addressed. The disadvantage of this method is that if at least one of the computers stops working, the entire network stops functioning, and the time it takes to transmit a signal to the required machine increases noticeably compared to other methods of connecting computers to a network.
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Star-shaped network With this organization, the network consists of several computers, each of which is connected to the same central device. This device is called HUB. The main disadvantage of this topology is that if the HUBa fails, the remaining nodes lose communication. The main advantage of such a connection is the ability to connect new nodes to the network without interrupting the operation of other nodes. Because of this important advantage of this type of network over others, as well as because of the relatively low cost, this type of network is the most common.
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Tree network A network that contains more than two end nodes and at least two intermediate nodes, and in which there is only one path between the two nodes. Such a network is attractive from the point of view of control and expandability, but if a fault occurs in a node, all underlying nodes are disconnected from the network.
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Mesh Network A computer network topology in which each workstation is connected to all the others. This option is cumbersome and ineffective, despite its logical simplicity. An independent line must be allocated for each pair; each computer must have as many communication ports as there are computers on the network. For these reasons, the network can only have relatively small final dimensions.
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Peer-to-peer network All computers in a peer-to-peer network have equal rights. Any network user can access data stored on any computer.
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Advantages of peer-to-peer networks: They are the easiest to install and operate. The DOS and Windows operating systems have all the necessary functions that allow you to build a peer-to-peer network. Disadvantages: In peer-to-peer networks, it is difficult to resolve information security issues. Therefore, this method of organizing a network is used for networks with a small number of computers and where the issue of data protection is not fundamental.
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Hierarchical network In a hierarchical network, when the network is installed, one or more computers are pre-allocated to manage data exchange over the network and resource distribution. Such a computer is called a server. Any computer that has access to the server's services is called a network client or workstation. A server in hierarchical networks is a permanent storage of shared resources. The server itself can only be a client of a server at a higher hierarchy level. Therefore, hierarchical networks are sometimes called dedicated server networks.
“Purpose of the computer” - System unit. Computer device. Storage devices. Input Devices. Scanner (graphic information). RAM. CD, DVD discs. Storage devices. The system unit contains a power supply. The system unit is a case in which the main functional components of a personal computer are located.
“Types of structures” - Tabular type. Hierarchical type. Data structuring. Vertex weight. A graph in which all lines are directed is called a directed graph. Components of the graph. A structural model is a representation of an information sign system in the form of a structure. Graph. Weight displays the properties of a component or links on a graph.
"Data types" - Arithmetic expressions. Arithmetic expressions. Basic definitions. A character constant is any language character enclosed in single quotes. An algorithm is a clear sequence of actions necessary to solve a problem. Data types. Turbo Pascal. Reserved (service) words. In the Pascal language there are two logical constants TRUE and FALSE.
“Database” - Functions of an advanced database. Main menu view. Tools for collecting, processing and analyzing data for managing the quality of education. Demographic data. DB interface. Educational statistics data. Main groups of statistical data used in calculations. Economic data. Data used in the database.
“Digital cameras” - Examples of distortion of digital camera lenses. A display showing the frame before and after shooting. Color management. Consumables. Synchro contact. Batteries and power supplies. Color models. Laser printer device. Photosensitivity. Gamma selection. Trends in choosing a method for printing photographs.
“Operating system” - Interface – command line. Graphical user interface. Unified user interface. The operating system is the most important program. Each device has its own driver. Graphic shells. Graphical user interface. Unified software interface. Software.
There are 21 presentations in total
Creative work of student group 21/22 Velichkovskaya E.K.
Feodosia 2009
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Computer network (computer network, data network) - a communication system between two or more computers and/or computer equipment (servers, routers and other equipment)
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Classified:
by territorial distribution
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Local area network (LAN)
A network that usually covers a relatively small area or a small group of buildings
- Company
Typically, such networks connect computers located at distances (about 50–1000 meters) within one or more nearby buildings.
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City computer network
Connects computers within a city
City network - the provider's core network, points connected by high-speed channels. Distance - from 1 to 10 km.
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Regional network
connecting computers and local networks to solve common problems on a regional scale
Located within a specific territorial region
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Global network
association of computers and local networks located at a remote distance for the common use of world information resources.
Iain Foster
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Classified:
by departmental affiliation
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Departmental network
Belongs to one organization and is located on its territory:
- ATM network
- Railway ticket offices
- Theater box office, etc.
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State network
Used in government agencies
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Classified:
by type of transmission medium
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wired
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Twisted pair networks
Twisted pair is a type of communication cable that consists of one or more pairs of insulated conductors, twisted together (with a small number of turns per unit length), covered with a plastic sheath.
Currently, due to its low cost and ease of installation, it is the most common solution for building local networks.
Slide 15
Coaxial networks
Coaxial cable is a cable in which the inner wire is surrounded by a second shielding wire to reduce radio interference.
The main purpose of coaxial cable is signal transmission in various fields of technology
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Fiber Optic Networks
An optical fiber is a glass or plastic thread used to carry light within itself through total internal reflection.
Optical fiber can be used as a means for long-distance communication and building a computer network.
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Classified:
Wireless is a technology that allows you to create computer networks that fully comply with the standards for conventional wired networks (for example, Ethernet), without the use of cable wiring.
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Radio transmission
Radio communication is used to build highways (radio relay lines), to create local networks, and to connect remote subscribers to networks and highways of various types.
A wireless network works where a cable network does not.
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In the infrared range
Has a wide frequency range. Transmission is carried out with a narrow beam in the complete absence of lateral radiation.
The transmitter is a semiconductor emitting diode. A highly sensitive photodiode is used as a receiver.
High communication confidentiality.
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Classified:
By transmission speed
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Information transfer rate - the speed of data transmission, expressed in the number of bits, symbols or blocks transmitted per unit of time.
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Based on the speed of information transfer, computer networks are divided into low-, medium- and high-speed.
- low-speed (up to 10 Mbit/s),
- medium-speed (up to 100 Mbit/s),
- high-speed (over 100 Mbit/s);
A unit of signal transmission rate measured in the number of discrete transitions or events per second. If each event represents one bit, a baud is equivalent to bits/sec (this is often not the case in real communications).
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Classified:
by topology (geometric diagram of connecting network nodes)
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Linear network
This is a Point-to-Point network. With this organization, the network consists of two computers directly connected to each other. The advantage of such a network organization is its simplicity and relative cheapness, but the disadvantage is that only two computers can be connected in this way.
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Common bus
The network consists of several computers, each of which is connected to a common data bus for the network. A coaxial cable can act as a bus. The main disadvantage of this organization is that if the bus breaks, all network nodes lose communication. If it is necessary to connect another node to the network, then during installation work the connection will also be lost
Slide 26
Ring network
the network consists of several computers, each of which is connected to a cable closed in a ring. The signal is transmitted along the ring in one direction and passes from computer to computer. In this case, the computer, having received a signal from a neighboring machine, amplifies it and transmits it further along the ring. This happens until the signal reaches the computer to which it is addressed. The disadvantage of this method is that if at least one of the computers stops working, the entire network stops functioning, and the time it takes to transmit a signal to the required machine increases noticeably compared to other methods of connecting computers to a network.
Slide 27
Star network
With this organization, the network consists of several computers, each of which is connected to the same central device. This device is called HUB. The main disadvantage of this topology is that if the HUBa fails, the remaining nodes lose communication. The main advantage of such a connection is the ability to connect new nodes to the network without interrupting the operation of other nodes. Because of this important advantage of this type of network over others, as well as because of the relatively low cost, this type of network is the most common.
Slide 28
Tree network
A network that contains more than two end nodes and at least two intermediate nodes, and in which there is only one path between the two nodes. Such a network is attractive from the point of view of control and expandability, but if a fault occurs in a node, all underlying nodes are disconnected from the network.
Slide 29
Mesh network
A computer network topology in which each workstation is connected to all others. This option is cumbersome and ineffective, despite its logical simplicity. An independent line must be allocated for each pair; each computer must have as many communication ports as there are computers on the network. For these reasons, the network can only have relatively small final dimensions.
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Classified:
On organizing the interaction of computers
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Peer-to-peer network
All computers in a peer-to-peer network have equal rights. Any network user can access data stored on any computer.
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Advantages of peer-to-peer networks: They are the easiest to install and operate. DOS and windows operating systems have all the necessary functions that allow you to build a peer-to-peer network.
Disadvantages: In peer-to-peer networks, it is difficult to resolve information security issues. Therefore, this method of organizing a network is used for networks with a small number of computers and where the issue of data protection is not fundamental.
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Hierarchical network
In a hierarchical network, when the network is installed, one or more computers are pre-allocated to manage data exchange over the network and resource distribution. Such a computer is called a server.
Any computer that has access to the server's services is called a network client or workstation.
A server in hierarchical networks is a permanent storage of shared resources. The server itself can only be a client of a server at a higher hierarchy level. Therefore, hierarchical networks are sometimes called dedicated server networks.
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Advantages of hierarchical networks: The hierarchical network model is the most preferable, as it allows you to create the most stable network structure and more rationally distribute resources. Another advantage of a hierarchical network is a higher level of data protection
Disadvantages: Requires additional OS for the server. Higher complexity of installing and upgrading the network. The need to allocate a separate computer as a server
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Classified:
By switching methods
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Switching
This is the process of connecting subscribers of a communication network through transit nodes.
Communication networks must ensure that their subscribers communicate with each other. Subscribers can be computers, local network segments, fax machines or telephone interlocutors. As a rule, in public networks it is impossible to provide each pair of subscribers with their own physical communication line, which they could exclusively “own” and use at any time. Therefore, the network always uses some method of switching subscribers, which ensures the division of existing physical channels between several communication sessions and between network subscribers.
Each subscriber is connected to the switches by an individual communication line assigned to this subscriber. Communication lines stretched between switches are shared by several subscribers, that is, they are used together.
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Circuit switching
organization of a composite channel through several transit nodes from several sequentially “connected” channels for the duration of message transmission (operational switching) or for a longer period (permanent/long-term switching - switching time is determined administratively, that is, a technician came and switched channels for an hour, a day, a year, forever, etc., then he came and disconnected).
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Message switching
splitting information into messages that are transmitted sequentially to the nearest transit node, which, having received the message, remembers it and transmits it further in the same way. That is, it turns out like a conveyor belt.
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