Introduction to Data Communications and Computer Networks Chaiporn Jaikaeo Department of Computer Engineering Kasetsart University 01204325 Data Communications and Computer Networks Based on lecture slides by Assoc.Prof.Surasak Sanguanpong Revised 2020-07-14
37
Embed
Introduction to Data Communications and Computer Networks
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
Introduction to Data Communications and Computer Networks
Chaiporn Jaikaeo
Department of Computer EngineeringKasetsart University
01204325 Data Communications and Computer Networks
Based on lecture slides by Assoc.Prof.Surasak Sanguanpong
Revised 2020-07-14
2
Outline•Communications Model•Basic Data Communication Terminology•Protocols and Standards Organizations
•Networking• The Internet
3
Telecom vs. Datacom• Communications
◦ Transfer of data from one entity to another via some form of transmission medium
• Telecommunications◦ Communication over a distance by definition◦ All type of communications using signaling such as
voice (telephone), images (television), data (computers)
• Data communications◦ Subset of telecommunications that involves the
transmission and reception of data to and from computers and components of computer systems
Image by Pezibear, Alexas_Fotos, and Michael Schwarzenberger from Pixabay
◦ A set of rules governing data communications◦ Syntax: format of data block◦ Semantics: meaning of each section◦ Timing: speed and sequencing◦ etc.
•Standard◦ De facto (in practice) standards
◦ ® not approved but widely adopted
◦ De jure (in law) standards◦ ® approved by an organization
9
Examples of Standards OrganizationslList of some major standard bodies
10
ITU-T
• International standard organization that develops standard for telecommunications• Some well known standards
◦ V series◦ X series◦ H series◦ G Series
International Telecommunications Union –Telecommunication Standard Sector
11
ISO
•An International standard organization that develops standard for variety of fields
International Standards Organization
12
IETF
•A large open international community of network designers, operators, vendors, and researchers concerned with the evolution of the Internet architecture
Internet Engineering Task Force
13
IEEE
• The largest professional group involved in standards for computing, communications, electrical and electronics
Institute of Electrical and Electronics Engineers
14
Networks•A network is a set of two or more devices connected
Point-to-Point Connection•Only two devices share the medium• The entire capacity of the link is reserved for the
transmission between those two devices
Station Station
A direct link between two devices
A direct link between two devices
17
Multipoint Connection•More than two devices share the same medium• The capacity of the link is shared
StationStation
A link is sharedbetween several devices
StationStation Station
18
Direction of Data Flow
Simplex
Half-duplexType of Direction
Full-duplex
19
Simplex
Unidirectional
Computer Display
Hi….
TelevisionBroadcast station
•Data are only transmitted in one direction•One device can only transmit; the other can only receive
20
Half-duplex•Both stations may transmit; but only one at a time
(alternate in transmitting)• Example: Walkie-Talkies
Transmit from S1 to S2 at time T1
Transmitter/ReceiverTransmitter/Receiver Transmit from S2 to S1 at time T2
S2S1
21
Full-duplex• Full-Duplex operation can occur in two ways:
◦ two separate transmission path◦ channel is divided between signals traveling in opposite directions
• Example: telephones
Simulteneous send and receive data from each other
Transmitter/ReceiverTransmitter/Receiver
S2S1
22
Data Transmission
Parallel
Serial
Asynchronous
Data Transmission
Synchronous
23
Parallel Transmission• Simultaneous transmission results in high speed•Required more data lines, hence higher cost•Usually limited to short distances because its costs and