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What does it mean?

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233 million host computers in January 2004 –Up from 2.2 million 10 years ago Up 62 million since January 2003 Goes into all countries in the world –Even the old Afghanistan had one official internet-enabled computer Provides audio and video in addition to text. Mail transmission takes less than 1 sec. * Source:

"Ma Bell": 1) Owned 22 companies that provided communications services. 2) Had a monopoly.

1)22 companies were spun off into 7 independent companies called Bell operating companies (BOC). 2)AT&T was restricted to providing only long distance services. 3)US was divided into 200 LATA's. ( L ocal A ccess and T ransport A reas). 4)Each BOC operated in several LATA's. LATA-map, California: Source: lata_map/california.htmwww.flatrate800.com/ lata_map/california.htm

1) Other long distance carriers like MCI, Sprint emerged to compete with AT&T. 2) AT&T and BOC's could enter other areas of business also. 3)Initially, AT&T rates were controlled by FCC, but later relaxed.

New communications bill was passed in 1996: 1) Cable companies are allowed to enter phone services. 2) Long distance and local companies are allowed to compete with one another. 3) They can all provide internet services. 4) Now, AT&T is breaking itself up further… (AT&T Wireless, AT&T Broadband, AT&T Business Services, and AT&T Consumer Services) Sweeping changes in the works.… Frenetic pace of merger and acquisition activity.. Factors: deregulation, consolidation, technology, integration, privatization, globalization.... How does this affect the Consumer? Businesses? Network designer?

bits A Network moves bits (text, data, audio, video, programs) from one point to another by means of a transmission system in an economical, reliable and fast way. It provides connectivity (physical, logical, etc.). 1) Wide Area networks: span several hundred or thousands of miles. e.g. Internet, SABRE reservation network. 2) Local Area network: span a few miles (usually less than 10) e.g., a campus, or a few buildings. 3) Home Local Area Network: span a few thousand square feet. Some networks are centralized and others distributed. Some are wired and others wireless.

CustomersThe Content Video/Audio:  movies  news  sports  art Print:  newspapers  magazines  books Communication:  voice  video  Education Shopping Internet, et al. The Pipe Airwaves:  broadcast TV  cellular telephone  satellite/ microwave Retail outlets for CDs, tapes, print:  Blockbuster  Seven-Eleven Phone Network:  copper  fiber Optics Cable Networks The Box Telephone Personal Computer Television VCR Pager The MICE Industry Supply Chain A network is the "pipe" that delivers "content" to the "box" at the customer site. (Source: Clockspeed, by Charles Fine, Perseus Books, 1998, Page 23.)

SIGNAL LEVEL TIME DIGITAL SIGNAL

The most fundamental unit of digital communication is a bit. A character of text is represented in 8 bits (or a byte) A terminal screen normally has 25 lines x 80 characters/line = 2000 characters => bits

An Analog signal like voice can be stored in digital form by sampling it 4000 times per sec. Say, each sample is given a discrete level between 0 and 15 (i.e. each level takes 4 bits). Therefore, need 4000 x 4 = bits to store one second of voice. Voice Kai Larsen: This is based on Nyquist’s Theorem. Kai Larsen: This is based on Nyquist’s Theorem.

-A Picture on the computer screen contains 1000 x 600 picture elements (pixels) 6 x 10 5 bits = 600,000 bits -Color Picture with 16 different colors would need => 4 x 6 x 10 5 bits = 2.4 million bits - For continuous motion we need about 30 pictures/sec - Therefore, one second of video requires 72 million bits. Video

Data travels from one point to another just like gas travels in a pipeline from Texas to Colorado… Houston, TXBoulder, CO BANDWIDTH = 56,000 bits/sec 56,000 bits/sec BANDWIDTH =1,544,000 bits/sec 1,544,000 bits/sec Bandwidth is the carrying capacity of a "pipe" that transmits data. It is usually measured in Bits per Second. This is a very important concept!

Local Loop END USER COMM. EQPT. INSTRUMENTS 1) Telephone set 2) MODEM 3) Multiplexer 4) Terminals 5) Front-end Comm. Processor 6) Concentrators TEL. CO. CENTRAL OFFICE TEL. CO. CENTRAL OFFICE Switching Trunk Line or IXC or IOC END-USER COMMUNICATIONS EQUIPMENT (copper, cable, fiber, satellite, wireless)