UNIT 4. Networks
Text 9
Network Structures
I. Read and translate the text:
A network is a way to connect computers for communication, information exchange, and resource sharing. The four most important benefits of networking are simultaneous access to programs and data, peripheral sharing, streamlined communications, and easier backups. E-mail, videoconferencing, and teleconferencing are examples of the personal communications that can be conducted over a network or the Internet.
Networks can be categorized in different ways, such as by geography (how much terrain they cover) or by the use or absence of a central server.
A local area network (LAN) consists of computers that are relatively near one another. A LAN can have a few PCs or hundreds of them in a single building or in several buildings. On a network, data is broken into small groups called packets before being transmitted from one computer to another. A packet is a data segment that includes a header, payload, and control elements that are transmitted together. The receiving computer reconstructs the packet into the original structure. The payload is the part of the packet that contains the actual data being sent. The header contains information about the type of data in the payload, the source and destination of the data, and a sequence number so that data from multiple packets can be reassembled at the receiving computer in the proper order. Each LAN is governed by a protocol, which is a set of rules and formats for sending and receiving data. TCP/IP, IPX/SPX, and NetBEUI are examples of network protocols.
LANs can be connected by a bridge or router to create a much larger network that covers a larger geographic area. To connect LANs, a gateway may be required to enable them to share data in a way that the different LANs can understand.
A wide area network (WAN) is the result of connecting LANs through public utilities.
Many networks are built around a central server. The PCs that connect to the server are called nodes. In a file server network, each node has access to the files on the server but not necessarily to files on other nodes. In a client/server network, nodes and the server share the storage and processing workload.
A peer-to-peer network is a small network that usually does not include a central server. In a peer-to-peer network, users can share files and resources on all the network's nodes.
Vocabulary:
network ['netwq:k] – сеть
to network – организовывать, создавать сеть
way [wei] – способ
information exchange [‚infq'meiSn iks'tSeinG] – обмен информацией
resource [ri'sLs] – ресурс
benefit ['benifit] – преимущество
simultaneous access [‚simql'teinjqs 'xkses] – одновременный доступ
peripheral [pq'rifqrql] – периферийное оборудование
streamlined ['stri:mlaind] – потоковый
to back up [bxk'Ap] – создавать резервную копию
backup ['bxk 'Ap] – создание резервной копии
electronic mail (e-mail) [ilek'tronik meil] – электронная почта
videoconference ['vidiqu'konfqrqns] – видеоконференция
teleconference ['teli'konfqrqns] – телеконференция
to conduct [kqn'dAkt] – проводить
to categorize ['kxtigqraiz] – классифицировать
terrain ['terein] – территория, район
to cover ['kAvq] – покрывать, охватывать
absence ['xbsqns] – отсутствие
central server ['sentrql 'sq:vq] – центральный сервер
local area network (LAN) ['lqukql 'Fqriq 'netwq:k] – локальная вычислтель-ная сеть (ЛВС)
relatively ['relqtivli] – относительно
near [niq] – близкий
packet ['pxkit] – пакет, блок данных
to transmit [trxnz'mit] – передавать
header ['hedq] – заголовок
payload ['peilqud] – блок данных
to receive [ri'si:v] – получать
to reconstruct ['ri:kqns'trAkt] – восстанавливать
original [q'riGqnl] – первоначальный
destination [‚desti'neiSn]– пункт назначения, адресат информации
sequence number ['si:kwqns 'nAmbq] – порядковый номер
33. to reassemble ['ri:q'sembl] – перетранслировать
to govern ['gAvqn] – управлять
rule [ru:l] – правило
bridge [briG] – мост
router ['ru:tq] – маршрутизатор сети
gateway ['geitwei] – машина-шлюз
to enable [i'neibl] – давать возможность
wide area network (WAN) [waid 'Fqriq 'netwq:k] – глобальная вычисли-тельная сеть
public utilities ['pAblik ju:'tilitiz]– коммунальные службы
node [nqud] – узел сети
file server network [fail 'sq:vq 'netwq:k] – сеть с сервером файлов
necessarily ['nesisqrili] – необходимо
client ['klaiqnt]– клиент
workload ['wq:klqud] – рабочая нагрузка
peer-to-peer network ['piqtq'piq 'netwq:k] – одноранговая сеть
II. Answer the questions:
What is a network?
What are the most important benefits of networking?
What types of the personal communications can be conducted over a network?
How can networks be categorized?
What is a LAN?
What is called a packet? What does it include?
What does the payload contain?
What information does the header include?
How is a network governed?
Give the names of some most commonly used protocols.
What devices can LANs be connected by?
What is a WAN?
What is the difference between a file server network and a client/server network?
What is a peer-to-peer network?
III. Tell whether the following statements are true or false:
E-mail systems enable users to exchange text messages, but not to share data files such as word processing documents.
A teleconference is the same thing as a videoconference.
Any network within a single building is considered to be a LAN, but if the network extends (простирается) beyond (за пределы) that building, it is no longer (больше не) considered a LAN.
On a network, data is broken into small groups – called payloads – before being transmitted from one computer to another.
TCP/IP, IPX/SPX, and NetBEUI are examples of common networking protocols.
If you need to connect two different types of networks, you can use a bridge to translate the data so the networks can communicate.
The individual computers on a network are called gateways.
In a client/server network, individual computers share the processing and storage workload with a central server.
In a peer-to-peer network, individual computers can access one another’s resources.
All peer-to-peer networks include a network server.
IV. Fill in the blanks:
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