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Unformatted text preview: ) per seco nd, Mbps = millio n bits (o r megabits) per seco nd, Gbps = billio n bits
(o r gigabits) per seco nd (o r terabit), and Tbps = trillio n bits (o r terabits) per seco nd. Remember, there are eight bits in a byte, and o ne byte is a single character. One megabyte is
ro ughly equivalent to o ne digital bo o k, f o rty-f ive seco nds o f music, o r twenty seco nds o f
medium-quality video .R. Farzad, “The Truth abo ut Bandwidth,” BusinessWeek, February 3,
2010. But yo u can’t just divide the amo unt o f bytes by eight to estimate ho w many bits yo u’ll
need to transf er. When a f ile o r o ther transmissio n is sliced into packets (usually o f no mo re
than abo ut 1,500 bytes), there’s so me o verhead added. Tho se packets “wrap” data chunks in an
envelo pe surro unded by so urce and destinatio n addressing and o ther impo rtant inf o rmatio n. Here are so me ro ugh demand requirements f o r streaming media. Fo r streaming audio like
P ando ra, yo u’d need at least 150 Kbps f o r acceptable regular quality, and at least 300 Kbps f o r
high quality.P ando ra, “Frequently Asked Questio ns,” http:/ / blo g.pando ra.co m/ f aq. Fo r
streaming video (via Netf lix), at a minimum yo u’d need 1.5 Mbps, but 3.0 Mbps will ensure
decent video and audio . Fo r what Netf lix calls HD streaming, yo u’ll need a minimum o f 5 Mbps,
but wo uld likely want 8 Mbps o r mo re to ensure the highest quality video and audio .LG
Kno wledge Base, “Bandwidth Needed f o r Instant Streaming,”
http:/ / lgkno wledgebase.co m/ kb/ index.php?View=entry&EntryID=6241. Cable Broadband
Ro ughly 90 percent o f U.S. ho mes are serviced by a cable pro vider, each capable o f using a thick
co pper wire to o f f er bro adband access. That wire (called a coaxial cable o r co ax) has shielding that reduces electrical interf erence, allo wing cable signals to travel lo nger distances witho ut
degrading and with less chance o f interf erence than co nventio nal telepho ne equipment. One po tential weakness o f cable techno lo gy lies in the f act t...
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This document was uploaded on 01/31/2014.
- Winter '14