* What 3 things must be present for communication to occur? * Transmission media, data transmission, cooperation
* Define Bandwidth
* Amount of data can be transferred from one point to another in a certain time * Define attenuation
* Loss of power in a signal as it travels from sending device to receiving device * What is a protocol and why is it important in electronic communication? * Rules governing data communication including error detection, message length, speed * What is the difference between a switch and a router?
* Modem – Modulator Demodulator. Connects user to internet. Not required for wifi * Switch – main linking device within a network
* Distinguish between main two types of conducted media (wired media) * Electrical Conductors – Twisted pair cable consists of two copper lines twisted around each other – Coaxial cables used for long-distance telephone transmissions and local area networks * Light Conductors – Fiber-optic cables are glass tubes surrounded by concentric layers of glass to form a light path through wire cables * Distinguish between centralized data processing, decentralized data processing and distributed * Centralized – Processing done at one central computer. Can exercise tight control on system operations and apps. Can be lacking responsiveness. Not common * Decentralized – Each user/department has own computer for processing. More responsive to users. Lacks coordination/high cost/duplicates efforts * Distributed – Centralized control and decentralized operations. More compatible, more features, more responsive. Dependence on communication. Incompatibility between equipment. More challenging management. * Examples of WAN, MAN, LAN
* WAN – Wide area network. Spans several cities/states/countries. * MAN – Metropolitan are network. Comm for multiple organizations in a city. * LAN – Local area network Connects hosts that are in close proximity. * If network topology is star/ring/bus/hierarchy or mesh network * Represents networks physical layout
* Star – Central computer with a series of nodes
* Ring – Each computer manages its own connectivity. Each node connected to two other nodes * Bus – Connected nodes along network segment. Ends of cable aren’t connected * Hierarchical – Combines computers with different processing strengths in different organizational levels * Mesh – Every node is connected to every other node * What is packet switching? Advantages / disadvantages
* Slicing digital messages into packets, sending along different comm paths as available, reassembles at destination. * Advantage – Adaptive routing for efficient line usage. Don’t need same data rates. Can be prioritized. * Disadvantage – Delay due to multiple node decision points, variable delays cause jitter, extra overhead * Two main protocols from basis of the industry standard suite of comm protocols? * TCP/IP – standard. Enables internet communication. TCP – transmission control protocol. IP – Internet protocol. * Client/Server Computing – Powerful clients (PC) connected to network with one or more server computers performing common function. Presentation, application, data mgmt. * Explain convergence in data communication.
* Integrating voice, video, data so multimedia information can be used for decision making. It required network upgrades. Common apps- ecommerce, entertainment, conferencing.
LECTURE 8 – INTER/INTRA/EXTRA NETS
* Identify 3 phases of internet evolution, approximate year of transition from one to next * Innovation Phase (1961-1974)
* Institutionalization (1974-1995)
* Commercialization (1995-Present)
* Who is credited with inventing the WWW
* Tim Berners-Lee
* Differences between domain name/IP address/ URL
* Domain name –...