Introduction to Data Communication (Basic Networking)

INTRODUCTION TO DATA COMMUNICATION

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TELECOMMUNICATIONS AND DATA COMMUNICATIONS• TELECOMMUNICATIONS – IS A GENERAL TERM

FOR THE ELECTRONIC TRANSMISSION OF INFORMATION OF ANY TYPE INCLUDING TELEVISION PICTURES, SOUNDS, FACSIMILES AND DATA IN THE FORM OF ELECTRONIC SIGNALS OR IMPULSES, SENT EITHER AS AN INDIVIDUAL MESSAGE BETWEEN TWO PARTIES OR AS A BROADCAST TO BE RECEIVE AT MANY LOCATIONS

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• . IT COULD ALSO BE REFFERED TO AS COMMUNICATION OVER A DISTANCE USING TECHNOLOGY TO OVERCOME THAT DISTANCE.

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• TELECOMMUNICATIONS USUALLY INVOLVES A SENDER OF INFORMATION AND ONE OR MORE RECIPIENTS LINKED BY A TECHNOLOGY.• EX. TELEPHONE SYSTEM – THAT

TRANSMIT INFORMATION FROM ONE PLACE TO ANOTHER.

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TELECOMMUNICATIONS AND DATA COMMUNICATIONS

TELECOMMUNICATIONS MESSAGE CAN BE SENT IN A VARIETY OF WAYS AND BY A WIDE RANGE OF DEVICES.1. POINT-TO-POINT - THE MESSAGE CAN BE SENT FROM ONE SENDER TO A SINGLE RECEIVER. EX. TELEPHONE CONVERSATION BETWEEN 2 PEOPLE OR A FACSIMILE (FAX ) MESSAGE.

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2. POINT-TO-MULTIPOINT – THE MESSAGE CAN BE SENT FROM ONE SENDER TO MANY RECEIVER. THIS OFTEN CALLED BROADCAST. EX. COMMERCIAL RADIO AND TELEVISION PROGRAMMING

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DATA COMMUNICATIONS CONCEPTS

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DATA COMMUNICATIONS CONCEPTS2. DATA COMMUNICATION IS THE

PROCESS OF COMMUNICATING INFORMATION IN BINARY FORM BETWEEN TWO POINTS. IT IS SOMETIMES CALLED “COMPUTER COMMUNICATION” BECAUSE MOST OF THE INFORMATION INTERCHANGED TODAY IS BETWEEN COMPUTERS, OR BETWEEN COMPUTERS AND THEIR TERMINALS, PRINTERS OR OTHER PERIPHERAL DEVICES.

BY: GILBERT HELD 8

DATA COMMUNICATIONS CONCEPTS3. DATA COMMUNICATIONS INVOLVES

DATA TRANSFER FROM ONE COMPUTER TO ANOTHER THROUGH A COMMUNICATIONS MEDIUM SUCH AS TELEPHONE, A MICROWAVE RELAYS, A SATELLITE LINK OR PHYSICAL CABLE.

MICROSOFT PRESS COMPUTER DICTIONARY

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DATA COMMUNICATIONS CONCEPTS

IN ESSENCE, ELECTRONIC COMMUNICATIONS IS THE TRANSMISSION, RECEPTION AND PROCESSING OF INFORMATION WITH THE USE OF ELECTRONIC CIRCUITS.

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• INFORMATION IS DEFINED AS KNOWLEDGE OR INTELLIGENCE COMMUNICATED OR RECEIVED.

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DATA COMMUNICATIONS CONCEPTS

• TRANSMISSION MEDIUM IS A CHANNEL FOR TRANSFERRING INFORMATION FROM THE SOURCE TO THE DESTINATION.

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DATA COMMUNICATIONS CONCEPTS

• IT CAN BE CLASSIFIED INTO TWO MAJOR CLASSES NAMELY THE BOUNDED AND UNBOUNDED MEDIUM , BASED ON HOW THE CARRIER SIGNAL PROPAGATES THROUGH THE CHANNEL.

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DATA COMMUNICATIONS CONCEPTS

• IN A BOUNDED MEDIUM, THE SIGNALS ARE CONFINED TO THE MEDIUM AND DO NOT LEAVE IT (EXCEPT FOR SMALLER LEAKAGE AMOUNTS). A PAIR OF WIRES, COAXIAL CABLE, WAVEGUIDE, AND OPTICAL-FIBER CABLE ARE EXAMPLES OF BOUNDED MEDIA.

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BOUNDED MEDIA

• THE ATMOSPHERE, THE OCEAN, AND OUTER SPACE ARE ALL EXAMPLES OF UNBOUNDED MEDIA, IN WHICH ELECTROMAGNETIC SIGNALS ORIGINATED BY THE SOURCE RADIATE FREELY INTO THE MEDIUM AND SPREAD THROUGHOUT IT. WHEN THE SIGNAL IS RADIATED FROM THE TRANSMITTER, IT RADIATES EQUALLY IN ALL DIRECTIONS (UNLESS RESTRICTED) AND CONTINUES FOREVER ONWARD.

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UNBOUNDED MEDIA

UNBOUNDED MEDIA• AS IT MOVES FARTHER FROM THE

SOURCE, THE ENERGY IS SPREAD OVER A LARGER AREA, SO THE LEVEL CONTINUALLY GETS WEAKER AT GREATER DISTANCES. AS THE WAVE MOVES THROUGH THE MEDIUM, IT IS AFFECTED BY NATURAL DISTURBANCES THAT CAN INTERFERE WITH THE SIGNAL.

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• INFORMATION DESTINATION OR SIMPLY DESTINATION COULD BE REMOTE COMPUTER OR ANY COMMUNICATING DEVICE TO WHICH THE MESSAGE IS ADDRESSED AND IS INTENDED TO BE CONVEYED.

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DATA COMMUNICATIONS CONCEPTS

SIMPLIFIED BLOCK DIAGRAM OF A DATA COMMUNICATION SYSTEM

FIG. 1. SIMPLIFIED BLOCK DIAGRAM OF DATA COMMUNICATION SYSTEM

INFORMATION SOURCE TRANSMISSION MEDIUM INFORMATION

DESTINATION

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GENERAL DESCRIPTION OF A DATA COMMUNICATION SYSTEM

1. TRANSMITTER – A TRANSMITTER CAN BE ANY CIRCUIT OR ELECTRONIC DEVICE DESIGNED TO SEND ELECTRONICALLY ENCODED DATA TO ANOTHER LOCATION. TRANSMITTER CAN ALSO BE CALLED AS A SOURCE.

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GENERAL DESCRIPTION OF A DATA COMMUNICATION SYSTEM

2. TRANSMISSION PATH OR CHANNEL – A PATH OR A LINK THROUGH WHICH INFORMATION PASSES BETWEEN TWO DEVICES. IN COMMUNICATIONS, A MEDIUM FOR TRANSFERRING INFORMATION ALSO KNOWN AS LINE OR CIRCUIT. A COMMUNICATIONS CHANNEL CAN CARRY INFORMATION IN MANY FORMS SUCH AS DATA, SOUND AND/OR VIDEO IN EITHER DIGITAL OR ANALOG FORM.

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GENERAL DESCRIPTION OF A DATA COMMUNICATION SYSTEM

3. RECEIVER – IN DATA COMMUNICATIONS SENSE, A RECEIVER COULD BE ANY DEVICE DESIGNED TO RECEIVE ANY CONVEYED MESSAGE FROM THE TRANSMITTER OR THE SOURCE.

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THE UNIVERSAL SEVEN-PART CIRCUIT OF DATA COMMUNICATION SYSTEM

POINT A POINT B

TRANSMISSION CHANNEL

DTE – DCE INTERFACE DCE – DTE INTERFACE

BLOCK DIAGRAM

1. THE DATA TERMINAL EQUIPMENT (DTE) AT POINT A2. THE INTERFACE BETWEEN THE DTE AND THE DATA CIRCUIT-

TERMINATING EQUIPMENT (DCE) OR OFTEN DATA COMMUNICATIONS EQUIPMENT AT POINT A.

3. THE DCE AT POINT A4. THE TRANSMISSION CHANNEL BETWEEN POINTS A AND B5. THE DCE AT POINT B.6. THE DCE-DTE INTERFACE AT POINT B7. THE DTE AT POINT B.

DTE DCE DCE DTE

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THE UNIVERSAL SEVEN-PART CIRCUIT OF DATA COMMUNICATION SYSTEM

COMPUTER

MODEM

COMPUTER

MODEM

DIGITAL SIGNAL DIGITAL SIGNAL

ANALOG SIGNAL

PICTORIAL VIEW

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DATA COMMUNICATION APPLICATIONS

1. INTERNET – GLOBAL NETWORK WHICH IS A MORE SOPHISTICATED ABILITY TO ACCESS REMOTE PROGRAMS OR FILES.

- WE CAN RECEIVE AND SEND ELECTRONIC MAILS FROM ANY USERS AROUND THE WORLD.

- PEOPLE CAN SIMULTANEOUSLY TALK TO EACH OTHER THROUGH THE USE OF VIDEO CONFERENCING OR TELECONFERENCING WHICH IS AN ONLINE, REALTIME SYSTEM OF HOLDING CORPORATE MEETINGS, PLANNING SESSIONS, CLIENT INQUIRIES AND THE LIKE.

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• 2. ACCESS TO REMOTE PROGRAMS - LOGMEIN PRO SUPPORTS DESKTOP REMOTE

CONTROL, FILE TRANSFER, AND REMOTE PRINTING. - VIRTUAL NETWORK COMPUTING (VNC) TECHNOLOGY

ENABLES SHARING A COPY OF ONE COMPUTER'S SCREEN DISPLAY WITH ANOTHER COMPUTER OVER A NETWORK CONNECTION. VARIOUS VNC CLIENT AND SERVER PACKAGES EXIST, BASED ON COMMON NETWORK PROTOCOLS, SUPPORTING DIFFERENT PLATFORMS.

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DATA COMMUNICATION APPLICATIONS

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3. ACCESS TO REMOTE DATABASE(My SQL)3. FUTURE APPLICATIONS – MOBILE

PHONE, WIRELESS PHONE, WIRELESS APPLICATION PROTOCOL (*WAP) USED ON MOBILE PHONES TO CONNECT TO INTERNET

* TECHNICAL STANDARD FOR ACCESSING INFORMATION OVER A MOBILE WIRELESS NETWORK.

COMPUTER NETWORK GOALS AND/OR ADVANTAGES

1. RESOURCE SHARING

2. HIGH RELIABILITY

3. SAVING MONEY

4. PROVIDE POWERFUL

COMMUNICATION MEDIUM27

DATA COMMUNICATIONS STANDARDS

DATA COMMUNICATION STANDARDS OR PROTOCOLS ARE SIMPLY A SET OF RULES THAT WERE ESTABLISHED FOR USE IN THE COMPUTER INDUSTRY BY THE VARIOUS INTERNATIONAL BODIES. IT IS CONCERNED PRIMARILY WITH EITHER THE INTERNAL OPERATION OF THE COMPUTER OR THE CONNECTION OF LOCAL PERIPHERAL DEVICES.

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DATA COMMUNICATIONS STANDARDS

A COMMUNICATION PROTOCOL COULD BE DESCRIBE AS A SET OF RULES OR STANDARDS DESIGNED TO ENABLE COMPUTERS TO CONNECT WITH EACH OTHER AND TO EXCHANGE INFORMATION WITH THE MINIMUM POSSIBLE ERRORS REGARDLESS OF THE DEVICE’S MANUFACTURER. THE PROTOCOL GENERALLY ACCEPTED FOR STANDARDIZING OVERALL COMPUTER COMMUNICATIONS IS A SEVEN-LAYER SET OF SOFTWARE AND HARDWARE GUIDELINES KNOWN AS THE OPEN SYSTEM INTERCONNECT (OSI LAYERS).

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CLOSED SYSTEMS VS. OPEN SYSTEMSOPEN SYSTEMS– A TERM USED TO DESCRIBE ANY COMPUTERS OR

PERIPHERALS DESIGN THAT HAS PUBLISHED SPECIFICATIONS. IT IS DESIGNED TO INCORPORATE ALL DEVICES REGARDLESS OF MANUFACTURER OR MODEL THAT CAN USE THE SAME COMMUNICATIONS FACILITIES AND PROTOCOLS.

– OPEN SYSTEMS ENABLE EQUIPMENT PRODUCED BY ONE VENDOR TO BE USED WITH EQUIPMENT FROM ANY VENDOR THAT COMPLIES WITH THE STANDARDS.

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CLOSED SYSTEMS VS. OPEN SYSTEMSCLOSED SYSTEMS1.A TERM USED TO DESCRIBED ANY COMPUTER DESIGN

WHOSE SPECIFICATIONS ARE NOT FREELY AVAILABLE. SUCH PROPRIETARY SPECIFICATIONS MAKE IT DIFFICULT OR IMPOSSIBLE FOR THIRD PARTY VENDORS TO CREATE ANCILLARY DEVICES THAT WORKED CORRECTLY WITH A CLOSED-ARCHITECTURE MACHINE.

2. CLOSED SYSTEMS RESULTED IN THE PROLIFERATION OF PROPRIETARY SYSTEMS WHERE ONLY PRODUCTS COMING FROM THE SAME MANUFACTURERS COULD WORK.

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