Computer Network

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Introduction to Networking Elementary Terminology of Networks History (Development) of Computer Networks Advantages of Computer Networks Disadvantages of Computer Networks Applications & Uses of Networks ARPANET Internet

» Data Communication » Data Communication Component » Data Transmission Modes » Types of Connections » Analog Transmission » Digital Transmission

Transmission Media Twisted Pair Cable Coaxial Cable Optical Fiber Wireless Communication Radio waves Microwave Infrared

Types of Computer Networks Personal Area Network Local area networks Metropolitan Area Network Wide Area Network Type of Network on the term purpose

Computer Network topologies Bus Topology Ring Topology Star Topology Mesh Topology Tree Topology Hybrid Topology

Networking Devices Hubs Switches Bridges Routers Gateways Wireless Access Point Modems Media Converters Firewalls

Wireless or Mobile Computing Evolution of mobile communication systems Second Generation Networks Third Generation Networks Fourth & Fifth Generation Networks Wireless Transmission Protocols Multiple Access Techniques Frequency Division Multiple Access Time Division Multiple Access Code Division Multiple Access Space Division Multiple Access

Computer Network Model Layered Tasks The OSI Model Physical Layer Data Link Layer Network Layer Transport Layer Session Layer Presentation Layer Application Layer TCP/IP Reference Model

Medium Access Methods ALOHA Slotted ALOHA CSMA CSMA / CD Collision-Free Protocols

Error Detection and Correction Types of errors Error Detecting Codes Simple Parity check Two-dimension Parity Check Checksum Cyclic redundancy check Error Correcting Codes

Network Security Network Security Threats Network Security Threats Prevention Why Three Encryption Techniques? Firewall

Computer Networ MCQ

Data Communication

Data communication refers to the movement of encoded information from one point to another by means of electronic transmission system. It can also be defined as the exchange of data between two devices via some form of transmission medium which can be wired or wireless. Another definition for data communications simply mean the transferring of digital information (usually in binary form) between two or more points (terminals). At both the source and destination, data are in digital form; however, during transmission, they can be in digital or analog form Information is carried by signal, which is a physical quantity that changes with time. The signal can be a voltage proportional to the amplitude of the voice like in simple telephone, a sequence of pulses of light in an optical fiber, or a radio-electric wave radiated by an antenna.
The fundamental purpose of data communication is to exchange information which is done by following certain rules and regulations called protocols and standards. Communications between devices are justified for the following reasons:
i. Reduces time and effort required to perform business task
ii. Captures business data at its source
iii. Centralizes control over business data
iv. Effect rapid dissemination of information
v. Reduces current and future cost of doing business
vi. Supports expansion of business capacity at reasonably incremental cost as the organization
vii. Supports organization’s objective in centralizing computer system
viii. Supports improved management control of an organization.

The effectiveness of a data communication system depends on three fundamental characteristics

Delivery

The system must deliver data to the correct destination. Data must be received by the intended device or user and only by that device or user.

Accuracy

The system must deliver data accurately. Data that have been altered in transmission and left uncorrected are unusable.

Timeliness

The system must deliver data in a timely manner. Data delivered late are useless. In the case of video, audio and voice data, timely delivery means delivering data as they are produced, in the same order that they are produced, and without significant delay. This kind of delivery is called real-time transmission.

Computer Network

Data Communication