Архитектура Аудит Военная наука Иностранные языки Медицина Металлургия Метрология
Образование Политология Производство Психология Стандартизация Технологии
Telecommunications network structure
Atelecommunicationsnetworkis a collection ofterminalnodes,linksandanyintermediatenodeswhich are connected so as to enabletelecommunicationbetween the terminals. Thetransmissionlinks connect the nodes together. The nodes usecircuitswitching,messageswitchingorpacketswitchingto pass the signal through the correct links and nodes to reach the correct destination terminal.
Each terminal in the network usually has a uniqueaddress,so messages or connections can be routed to the correct recipients. The collection of addresses in the network is called theaddress space.
Examples of telecommunications networks are:
Atelephonenetworkisatelecommunicationsnetworkusedfortelephonecallsbetween two or more parties.There are a number of different types of telephone network:
· Alandlinenetwork where the telephones must be directly wired into a singletelephone exchange. This is known as thepublic switched telephone networkor PSTN.
· Awirelessnetworkwhere the telephones aremobileand can move around anywhere within thecoverage area.
· A private network where a closed group of telephones are connected primarily to each other and use a gateway to reach the outside world. This is usually used insidecompaniesandcallcentersand is called aprivate branch exchange(PBX).
Publictelephoneoperators(PTOs) own and build networks of the first two types and provide services to the public under license from the national government.Virtual Network Operators(VNOs) lease capacity wholesale from the PTOs and sell ontelephonyservice to the public directly.
Thepublic switched telephone network(PSTN) is the aggregate of the world'scircuit-switchedtelephonenetworksthat are operated by national, regional, or localtelephonyoperators, providing infrastructure and services for publictelecommunication. The PSTN consists oftelephonelines,fiber optic cables,microwavetransmissionlinks,cellularnetworks,communications satellites, andundersea telephone cables, all interconnected byswitching centers, thus allowing any telephone in the world to communicate with any other. Originally a network of fixed-lineanalogtelephone systems, the PSTN is now almost entirelydigitalinitscorenetworkandincludesmobileand other networks, as well asfixedtelephones.
The technical operation of the PSTN adheres to the standards created by theITU-T. These standards allow different networks in different countries tointerconnectseamlessly. TheE.163andE.164standards provide a single globaladdressspacefor telephone numbers. The combination of the interconnected networks and the single numbering plan make it possible for any phone in the world to dial any other phone.
Awirelessnetworkis any type ofcomputernetworkthat uses wireless data connections for connecting network nodes.Wireless networking is a method by which homes,telecommunicationsnetworksand enterprise (business) installations avoid the costly process of introducing cables into a building, or as a connection between various equipment locations.Wirelesstelecommunications networks are generally implemented and administered usingradio communication. This implementation takes place at the physical level (layer) of the OSI modelnetworkstructure.Examples of wireless networks include cell phone networks, Wi-Fi local networks and terrestrial microwave networks.
Acellular networkormobilenetworkis a radio network distributed over land areas called cells, each served by at least one fixed-locationtransceiver, known as acellsiteorbase station. In a cellular network, each cell characteristically uses a different set of radio frequencies from all their immediate neighboring cells to avoid any interference.
When joined together these cells provide radio coverage over a wide geographic area. This enables a large number of portable transceivers (e.g., mobile phones,pagers, etc.) to communicate with each other and with fixed transceivers and telephones anywhere in the network, via base stations, even if some of the transceivers are moving through more than one cell during transmission.
Although originally intended for cell phones, with the development of smartphones,cellular telephone networksroutinely carry data in addition to telephone conversations.
Global System for Mobile Communications(GSM): The GSM network is divided into three major systems: the switching system, the base station system, and the operation and support system. The cell phone connects to the base system station which then connects to the operation and support station; it then connects to the switching station where the call is transferred to where it needs to go. GSM is the most common standard and is used for a majority of cell phones.
Ex. 6.True, false or no information.
1.Telecommunicationsnetworknodesare connected via transmissionlinks.
2. A public switched telephone networkorPSTNis a radio network distributed over land areas.
3. Acellular networkconsistsoftelephonelines,fiber optic cablesandundersea telephone cables.
4. The first global network was established usingelectrical telegraphy.
5. TheGSMmobilecommunicationnetworkis used by over 6 billion people worldwide.
6. In a mobile networka large number of portable phonescommunicate with each othervia base stations.
7. The PSTN includes now different networks.
Ex. 7. Answer the questions.
1. What nodes does a telecommunication network consist of?
2. What switching do these nodes use?
3. What examples of telecommunications networks do you know?
4. How many types of telephone networks are mentioned in the text?
5. Who owns and buildslandlinenetworksand wireless networks?
6. How many systems is the GSM network divided in?
7. What standards allow different networks in different countries tointerconnect?
8. What is a PBX?
9. What is the difference between PTOs and VNOs?
Ex. 8.Continue the sentence.
1. A private network is…
a)a radio network distributed over land areas called cells;
b)usually used insidecompaniesandcall centers;
c)operated by national, regional, or localtelephonyoperators.
2. Each terminal in the network has…
a)examples of telecommunications networks;
b)a different set of radio frequencies from all their immediate neighboring cells to avoid any interference;
c)auniqueaddress,so messages or connections can be routed to the correct recipients.
3. GSM is the most common…
a)standard used for a majority of cell phones;
b)typeofcomputernetworkthat uses wireless data connections;
c)combination of the interconnected networks and the single numbering plan.
4. Wireless networking is a method…
a)to avoid any interference;
b)toavoid the costly process of introducing cables into a building;
c)to communicate with each other moving through more than one cell during transmission.
Ex. 9.Match the words (1–6) with the definitions (A–G). Translate.
1. LAN. 2. PBX. 3. Wi-Fi. 4. GPS. 5. PSTN. 6. GSM.
A.Public Switched Telephone Network. A country`s telephone network.
B.Private Branch Exchange. A telephone system bought and used by a company in their office.
C.A network which covers a small physical area, for example one building.
D.A system which uses radio signals to allow a broadband connection to the Internet.
E.A system which allows receiver to identify its position anywhere on earth.
G.A worldwide standard for mobile phones making phones from one operator compatible with a different operator in another country.
Ex. 10.Make up a sentence using the words and phrases.
1. Decades, it, to set up, a global, takes, network. 2. In the network, called, is, the address space, the collection of addresses. 3. A huge, there, of different types, are, amount, of telephone networks. 4. For any phone in the world, it, possible, to dial any other phone, the combination of the interconnected networks, makes. 5. A lot of different tasks, perform, displaying e-books, can, many LCD e-readers, in addition to.
Физические носители информации, требовать огромных усилий, установить глобальную сеть, достигнуть терминала, внутри зоны охвата, различный набор частот, использовать беспроводные информационные соединения, большинство сотовых телефонов, избегать помех, наземные телефонные сети, сложные телекоммуникационные узлы связи, общаться через базовые станции.
Ex. 12.Translate into English. Use the construction „infinitive as attribute”.
Глобальная сеть, которую нужно установить; носители информации, которые будут использоваться;подводные кабели, которые следует изготовить;узел терминала, который будет заменен;помехи,которые необходимо устранить;уровеньпомех,которого нужно достигнуть;беспроводные телефонные соединения, которые требуется обновить;качество сотовых телефонов, которое будет улучшаться; радиочастоты, подлежащие изменению;зоны охвата, которые будут увеличены.
1. Два дня тому назад мы посетили фирму, которая устанавливает наземные телекоммуникационные сети. 2. Cуществуют различные виды телекоммуникационных сетей.3.Нампоказалиоптоволоконныекабели, которыедоходятдопомещенийклиентов. 4. Чтокасаетсяменя, япредпочитаюиспользоватьбеспроводныесотовыетелефоны. 5. Зонаохватаэтихустройствдостаточновелика. 6.Крометого, качествосвязипостоянноулучшается. 7. Cмоей точки зрения, самое лучшее качество предоставляет спутниковая связь.8.Использованиеэтоговидасвязипозволяетнамизбежатьпомех. 9. В общем и целом следует внедрять все доступные телекоммуникационные технологии. 10. Мы должны также учитывать стоимость устройств, которые будут использоваться в области телекоммуникаций.
Tospan, collection, asetoflaws, toestablish, interference, storage, via, bugs, fieldofdeveloping, toconsist of, to exist, the costly process, to realize, to use, to join.
Ex. 15.Translate into Russian. Explain the sequence of tenses.
1. They were informed yesterday that the company had paid all the accounts promptly. 2. The secretary said that she had prepared all the documents. 3. He informed the customers that their firm had ordered new equipment. 4. The sellers stated in their offer that orders were executed within six weeks. 5. The buyers stated in their enquiry that they had been cooperating with the firm since 2012. 6. The importers informed the suppliers that they wanted to know when delivery would be made, as the computers were urgently required.
Ex. 16.Choose the correct voice. Translate.
1. Currently information technology (is impacting/is impacted) all walks of life all over the world. 2. Computerized databases are extensively (using/used) to store all sorts of confidential data of political, social, economic or personal nature to support human activities and bringing various benefits to the society. 3. However, the rapid development of information technology globally also (has led/has been leading) to the growth of new forms of national and transnational crimes. 4. These crimes (having/have) no boundaries and may (affect/affecting) any country across the globe. 5. The new boundaries, which (manifest/are manifested) in the monitor screen, passwords etc. have (created/been created) new personalities, groups, organizations, and other new forms of social, economic, and political groupings in the cyber world of bits.
Ex. 17.Translate the following words into Russian. Say how they were formed.
Security-card-operated, day-to-day, word-processor, office-worker, risk-taking, ´export – ex´port, ´import – im´port, readable, installation, beautiful, helpless, disabled, misunderstand, understandable, briefly, impossible, aviator, amplify, amplifier, amplification.
Последнее изменение этой страницы: 2017-03-09; Просмотров: 1212; Нарушение авторского права страницы