Transcript Networking:

Networking:
COMPUTER CONNECTIONS
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Data Communications
It is a computer systems that transmit data over
communications or an exchange of data between two
devices via some form of transmission medium such as a
wire cable.
A network is a computer system that uses
communications equipment to connect two or more
computers and their resources.
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Putting together a Network
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Data Transmission
It is the process of sending digital or analog data over a communication
medium to one or more computing, network, communication or
electronic devices. It enables the transfer and communication of devices
in a point-to-point, point-to-multipoint and multipoint-to-multipoint
environment.
Types of Transmission
1.
Digital Transmission sends data as distinct pulses either on or off.
2.
Analog transmission is a continuous digital signal in the form of a
wave.
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Data Transmission
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Data Transmission
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Data Transmission
Modem is a device that converts a digital signal to an analog signal and vice versa.
INTERNAL MODEM
EXTERNAL MODEM
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Data Transmission
Integrated Services Digital Network (ISDN) is an
international communications standard for sending
voice, video, and data over digital telephone lines or normal
telephone wires. ISDN supports data transfer rates of
64 Kbps (64,000 bits per second).
Digital Subscriber Line (DSL) service uses advanced
electronics to send data over conventional cooper
telephone wires.
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Data Transmission
 Cable Modems, a speedster that uses the coaxial
television cables that are already in place without
interrupting normal cable TV reception. It can be used to
achieve extremely fast access.
 Cellular Modems can be used to transmit data over the
cellular telephone system
 Asynchronous Transmission (also called start/stop
transmission) is used, a special start signal is transmitted at
the beginning of each group of message bits- a group is
usually just a single character.
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Data Transmission
 Synchronous transmission is a little trickier because a
large block of characters is transmitted together in a
continuous stream. There are no call-to-action signals for
each character.
 Simplex transmission sends data in one direction only.
 Half-duplex transmission allows transmission in either
direction but only one way at a time.
 Full-duplex transmission allows transmission in both
directions at once.
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Communications Media
A communications medium is the physical means of data
transmission. The range of frequencies that a medium can
carry is known as its bandwidth, the measure of the
capacity of the link.
Types of Communication Media
 Wire pairs also known as twisted pair.
 Coaxial cables is known for sending
a strong signal.
 Fiber optics A technology that uses glass
(or plastic) threads (fibers) to transmit data.
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Communications Media
 Microwave transmission uses what is called line-of-sight
transmission of data signals through the atmosphere.
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Communications Media
 Satellite transmission is a form of microwave transmission in which a
satellite acts as the relay station. Its basic components are earth
stations, which send and receive signals, and satellite component called
a transponder. The transponder receives the transmission from an earth
station (uplink) amplifies
the signal, changes the
frequency and retransmits
the data to a receiving
earth station(the downlink)
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Communications Media
A protocol is a set of rules for the exchange of data between
a terminal and a computer or between two computers.
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Network Topologies
A physical layout of a network is called a topology.
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Network Topologies
 A star network has a central (hub) computer that is responsible for
managing the network.
 A ring network links all nodes together in a circular chain. Data
messages travel in only one direction around the ring.
 A bus network has a single line (the bus) to which all the network
nodes are attached. Computers on the network transmit data in the
hope that is will not collide with data transmitted by other nodes.
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Wide Area Networks (WAN)
Networks can be classified
by the geographical area
they cover. The largest in
scope is the wide area
network (WAN)
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Local Area Network
A local area network (LAN) is a
collection of computers,
usually personal computers
that share hardware, software
and data. LAN hooks
computers together through
communications media so that
each personal computer can
share the resources of the
others.
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Local Area Network
LAN Components
1. Network cable
2. Network interface card (NIC)connects each computer to the
wiring in the network
3. IP switches
4. Bridge- a hardware/software
combination that recognizes the
messages on a network and passes
on those addressed to nodes in
other networks.
5. Gateway- it lets a node
communicate with a computer on
another dissimilar network.
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Local Area Network
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The Work of Networking
1. Electronic mail or e-mail is the process of sending a message directly
from one computer to another, where it is stored until the recipient
chooses to receive it.
2. Facsimile technology uses computer technology and communications
links to send graphics, charts, text..etc
3. Groupware is any kind of software that lets a group of people share
things or track things together.
4. Teleconferencing is a method of using technology to bring people and
ideas together despite geographical barriers.
5. Electronic data interchange (EDI)
6. Electronic fund transfer (EFT)
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