Lesson 18
Text A. Computing Network Components.
Text B. Network Topology.
Ex.1 Translate into Russian:
Wave, backbone, dedicated, arrangement, responsible, approximately, peer-to-peer, wire, reference, single-mode fiber, shield.
Ex.2 Translate into English:
Свойство, кольцо, защищать, запускать, принадлежать, маркер, искать, звезда, окружать, медный, внешний, ссылаться.
Ex.3 Fill in the blanks:
Networks are usually classified using three properties: _________, _________, and _________. Topology specifies the geometric ________ of the network. Common topologies are a ________, _________, and _________. Protocol specifies a common set of _________ and _________ the computers on the network use to communicate. Most networks use _________, but some networks may use IBM's _________ _________ protocol. Architecture refers to one of the two major types of network architecture: _________and client/server (or server-based ). Sometimes they are used in _________.
Ex.4 Read and memorize the following words:
weak [wi:k] – слабый
(to) amplify [´æmplıfaı] - усиливать
traffic [´træfık] – трафик, поток обмена, рабочая нагрузка
amount [Ə´maunt] – количество
bottleneck [´bɔtlnek] – критический элемент, критический параметр, “узкое место” в системе
excessive [ık´sesıv] – излишний, чрезмерный
route [ru:t] – путь, маршрут, направлять
router - машрутизатор
(to) forward [´fɔ:wƏd] – передавать, ретранслировать
brouter [´bru:tƏ] – мост-машрутизатор
internetworking – организация сети, объединение сети, межсетевое взаимодействие
(to) deliver [dı´lıvƏ] – (пре)доставлять
gateway [´ɡeıtweı] – шлюз
(to) arrive [Ə´raıv] – прибывать
audible [´ɔ:dƏbl] – акустический, звуковой
(to) decide [dı´saıd] – решать
decision [dı´sıʒn] - решение
destination [ˏdestı´neıʃn] – место назначения, адресат, пункт назначения
average [´ævƏrıʤ] - средний
by an average – в среднем
protocol stack – стек (набор) протоколов
external [ek´stƏ:nƏl] – внешний
trunk [trʌnk] – магистраль
detect [dı´tekt] – обнаруживать, находить
error detection – обнаружение ошибок
loop [lu:p] – кольцо, петля, цикл
(data) throughput [´θru:put] – пропускная способность
(to) match [mæʧ] – подходить, соответствовать
verification [ˏverıfı´keıʃn] – верификация, проверка, контроль
Ex.5 Read and translate into Russian:
Computing network components
The following devices are used for linking different LANs or LAN segments together.
Repeaters
A
repeater takes a weak signal from one segment, regenerates it
(amplifies it), and passes it to the next segment. Repeaters do not
act as a filter to restrict the flow of problem traffic. A repeater
connects two segments of similar or dissimilarmedia,
regenerates the signal to increase transmitting distance and passes
all traffic in both directions.
Hubs
Hub's major
function is to replicate data it receives from one device attached
to it to all others. Hubs differ in the amount of devices that can
connect to them, the length of wire that can transmit on, and the
type of media they support. Hubs that connect a small number of
devices are usually referred to as mini-hubs. Hubs can be active,
passive and hybrid.
Bridges
Bridges
are simpler and less expensive then routers. Bridges make a simple
decision on which packets to send across two segments they connect.
Bridges can be used to expand the distance of a segment, reduce
traffic bottlenecks
resulting from an excessive number of attached computers, link
unlike physical media
such as twisted-pair
and coaxial
Ethernet
and link unlike network segments such as Ethernet
and Token
Ring,
and forward packets between them.
Routers
Routers connect two or more networks and forward data packets
between them. When data arrives from one of the segments, the router
decides to which segment to forward the data.
Even though each of the routers’ connections is to one physical network, that one network could connect to other networks through the use of other routers. Routers can be static and dynamic.
Brouters
A brouter combines the best of both a bridge and a router. A brouter can act like a router for one protocol and bridge for all the others. Brouters can route selected routable protocols, bridge nonroutable protocols, deliver more cost-effective and more manageable internetworking than separate bridges and routers.
Gateways
Gateways make
communications possible between different architectures and
environments. They repackage and convert data going from one
environment to another so that each can understand the other
environment's data.
A gateway takes the data from one environment, puts off its old protocol stack, and repackages it in the protocol stack from the destination network.
Modems
A modem is a device
that converts digital data originating from a terminal or computer,
to analog signals used by voice communication networks such as the
telephone system. At one end, modems convert the digital pulses to
audible tones and convert audio tones back to digital pulses at the
other.
The word "Modem" stands for "MOdulator-DEModulator".
Some of the modem characteristics are the following:
Transmission speed. Modems are available in different transmission speeds, which are measured in BPS (bits per second) also called BAUD rate. Standard modems speeds: 9600 baud, 14400 baud, 28800 baud, 33600 baud, 56800 baud.
Internal/External. Internal modems are electronic cards. An internal modem is installed in one of the computer's expansion slot. The external modem is connected to a computer using a serial cable to one of the computer's serial ports, and draws power from an external power source.
Error detection and correction. Nowadays most of the modems support advanced error detection protocols at the hardware level.
Compression. Most modems support a variety of data compression protocols. Using these protocols, the data throughput can rise by an average of 50%.
Ex.6 Answer the following questions.
Do repeaters act as a filter to restrict the flow of problem traffic?
Can hubs be different? What kinds of hubs do you know?
What is the reason for traffic bottlenecks?
Can bridges be used to link unlike network segments such as Ethernet and Token Ring?
What do routers forward between networks?
What features does a brouter combine?
What is measured in BPS (bits per second)?
Ex.7 Make up all possible combinations:
|
network data transmission modem internal expansion electronic external serial power error hardware destination |
segment modem slot cable port source detection correction level throughput card speed packet |
Ex.8 Comment on the rules of word-building:
Regenerate, dissimilar, decision, unlike, nonroutable, manageable, expansion, available, compression, detection, correction, destination, audible.
Ex.9 Choose one of the devices (e.g. a repeater) and enumerate its main functions.