LESSON-02-Communications and Computer Networking.pptx
- 2. Communications The message (data and information) is communicated via the signal. The transmission medium “carries” the signal. Communications
- 3. Telecommunications The electronic transmission of signals for communications, including such means as: Telephone Radio Television Telecommunication medium Anything that carries an electronic signal and interfaces between a sending device and a receiving device. Telecommunications
- 4. Data communications A specialized subset of telecommunications that refers to the electronic collection, processing, and distribution of data -- typically between computer system hardware devices. Data Communications
- 6. Computer Network The communications media, devices, and software needed to connect two or more computer systems and/or devices. Used to share hardware, programs, and databases across the organization. Fosters teamwork, innovative ideas, and new business strategies. Computer Network
- 7. Twisted Pair Wire Cable Insulated pairs of wires historically used in telephone service and to connect computer devices. Coaxial Cable Consists of an inner conductor wire surrounded by insulation, called the dielectric. The dielectric is surrounded by a conductive shield, which is surrounded by a non- conductive jacket. Coaxial cable has better data transmission rate than twisted pair. Types of Telecommunication Media
- 8. Fiber-optic Cable Many extremely thin strands of glass or plastic bound together in a sheathing which transmits signals with light beams. Can be used for voice, data, and video. Types of Telecommunication Media
- 9. Microwave Communications Line-of-sight devices which must be placed in relatively high locations. Microwave Usage Information is converted to a microwave signal, sent through the air to a receiver, and recovered. Types of Telecommunication Media
- 10. Satellite Transmission Communications satellites are relay stations that receive signals from one earth station and rebroadcast them to another. Types of Telecommunication Media
- 11. Cellular Transmission Signals from cells are transmitted to a receiver and integrated into the regular network. Types of Telecommunication Media
- 12. Infrared Transmission Involves sending signals through the air via light waves. Requires line-of-sight and short distances (a few hundred yards) Used to connect various computing devices such as handheld computers Types of Telecommunication Media
- 13. Telecommunication Devices Relay signals between computer systems and transmission media. Telecommunications System
- 14. Terminology Telecommunication Devices Analog Signal E.G. Electricity current Digital Signal A signal represented by bits Modems Devices that translate data from digital to analog and analog to digital
- 15. Modem Modulates a digital signal into an analog signal for transmission via analog medium, then demodulates the signal into digital for receiving. Device: Modem
- 16. Figure 6.11 Multiplexer Allows several telecommunications signals to be transmitted over a single communications medium at the same time. Device: Multiplexer
- 17. ISDN Technology that uses existing common- carrier lines to simultaneously transmit voice, video, and image data in digital form. Media: Integrated Services Digital Network (ISDN)
- 18. Distributed Processing Centralized Processing Data processing that occurs in a single location or facility. Distributed Processing Data processing that occurs when computers are placed at remote locations but are connected to each other via telecommunications devices. The computers are connected as a computer network.
- 19. By Topology A model that describes how computers are connected A logical model that describes how networks are structured or configured 24 Network Types
- 20. Network Types Structured Ring Bus Star Hierarchical Hybrid Unstructured Mobile Adhoc Network (MANET)
- 22. Network Topologies For local area networks, not for the Internet Ring A typology that contains computers and computer devices placed in a ring. Bus Computers and computer devices are on a single line. Each device can communicate directly to all devices on the bus. Star All computers are connected via a central hub.
- 23. Network Topologies Hierarchical Uses treelike structures with messages passed along the branches of the hierarchy Hybrid A mix of different kinds of structured topologies. It is what exactly the Internet looks like. Mobile Adhoc Network It is unstructured network topology Structure is changing dynamically. EG. Network of mobile phone.
- 24. Network Topologies Mobile Adhoc Network Network does not have specify topology Each computer in the network is moving around without locating in a fixed location Sending and receiving messages are difficulty problems
- 25. 27 Network Types by Size Local Area Network (LAN) Connects computer systems and devices in the same geographic area (can be Ring, Bus, Hierarchical, Star, Hybrid) Wide Area Network (WAN) Ties together large geographic regions using microwave and satellite transmission or telephone lines. International Network Links systems between countries.
- 26. A Typical LAN in a BUS Topology A Wide Area Network LAN & WAN
- 27. Applications and databases reside on specialized host computers. Servers do most or all of the processing and transmit the results to the client. 31 Client/Server Connection
- 28. 33 Communications Software Communications Software Provides error checking, message formatting, communications logs, data security and privacy, and translation capabilities for networks. Network Operating System (NOS) Systems software that controls the computer systems and devices on a network and allows them to communicate with each other. Network Management Software Enables a manager on a networked desktop to monitor the use of individual computers and shared hardware, scan for viruses, and ensure compliance with software licenses.