Week 1 Things you want to know

Week 1 This is a series of things you want to know as you walk away from the course. What elements make up a communication system? How do we classify communications systems? Give examples of each switching technology. Describe telecom standards bodies, give examples of standards. What are the two types of standards?

Elements of a Communication System Source - the originator of the message, whether it is a person or machine. Transmitter - the equipment that modifies the message (either data or voice) into the form required for transmission. Communications channel - the means of carrying the signal from the source to the destination.

Elements of a Communication System Transmission media - may be physical, like a copper wire or fiber optic cable, or atmospheric, like radio waves. Receiver - is the device that captures the message from the communications channel and converts it into a form that the person or machine at the destination can understand. Destination - the person or machine to whom the message is directed

Elements of a Communication System

Flow of Messages Simplex - the type of communication in which messages flow in only one direction, from source to destination. Half-duplex communication - occurs when messages travel in both directions between the source and the destination, but in only one direction at a time. Full-duplex communication - messages can travel over the communications channel in both directions simultaneously.

Flow of Messages

Relative Number of Sources and Destinations One-to-one communication - a single source sends information to a single destination. One-to-many communication - a single source simultaneously sends information to multiple destinations. Many-to-many communication - occurs when many sources issue messages to many destinations.

Relative Number of Sources and Destinations

10 Classification of Data Networks by Ownership Public Network – Owned by a common carrier Private Network – Built for exclusive use by a single organization Virtual Private Network – Encrypted tunnels through a shared private or public network

11 Classification of Data Networks by Switching Technology Circuit Switching – Connection-oriented networks, ideal for real- time applications, guaranteed quality of service Message Switching – Store-and-forward system Packet Switching – Shared facilities, Used for data communications Cell Switching – Fast processing of fixed length cells

12 Classification of Data Networks by Computing Model Distributed Computing – Client/Server set-up Centralized Computing – Thin-client architecture Some Useful Telecom Terms – Scalability: Ability to increase the power and/or number of users without major redesigns – RAID (Redundant Array of Independent Disks) – UPS (Uninterruptible Power Supply)

13 Classification of Data Networks by Type of Information Data Communications – Digital transmission of information Voice Communications – Telephone communications Video Communications – Cable TV or video conferencing

ANSI The ANSI (American National Standards Institute) - an organization composed of over a thousand representatives from industry and government who together determine standards for the electronics industry. ANSI does not dictate that manufacturers comply with their standards, but requests them to voluntarily comply.

TIA and EIA The EIA (Electronics Industry Alliance) - is a trade organization composed of representatives from electronics manufacturing firms across the United States. TIA (Telecommunications Industry Association) - focuses on standards for information technology, wireless, satellite, fiber optics, and telephone equipment.

IEEE IEEE (Institute of Electrical and Electronic Engineers) - an international society composed of engineering professionals. Its goals are to promote development and education in the electrical engineering and computer science fields.

ATIS ATIS (The Association for Telecommunications Industry Solutions) - a North American trade association made of thousands of companies that provide communications equipment and services. Its membership reviews emerging technology and agrees on standards and operating procedures to ensure that services and equipment supplied by multiple companies can be easily integrated.

ISO ISO (International Organization for Standardization) - a collection of standards organizations representing 130 countries with its headquarters located in Geneva, Switzerland. Its goal is to establish international technological standards to facilitate global exchange of information and barrier-free trade.

ITU The ITU (International Telecommunications Union) - a specialized United Nations agency that regulates international telecommunication usage, including radio and TV frequencies, satellite and telephony specifications, networking infrastructure, and tariffs applied to global communication. Provides developing countries with technical expertise and equipment to advance their technological base.

Standards De facto Standards Open Computing

Week 1 Links history.html history.html