Looking an explanation for throughput...

Steve-O · Post by **Steve-O** » Sun Jan 22, 2006 4:05 pm

Hey guys, it's been a while since I've posted here, but I read the posts almost daily. I'm a little confused about a bandwidth issue. Although everything is working perfectly, I am seeking an explanation as to the relationship between up/down bandwidth and throughput on an ADSL connection. My ISP provides 512 down and 128 up (yeah, I know...) and I have done speed tests online at different sites that indicate I am making full use of my bandwidth (allowing for overhead of course). My question involves throughput. If I have a 512 download capability, why is my throughput only 52 kbps? As soon as the download starts, it's around 92 or so, then gradually degrades to a stable 50 - 52kbps. When I connect at work to a wireless AP, the throughput is 498 kbps. Since it's roughly ten times higher, I'm assuming the bandwidth there is about 5 mbps. Also, the other night I was at home and got a stable, sustained throughput of 82 kbps! I just don't fully understand the relationship between bandwidth and throughput I guess. Any knowledge/wisdom you can share in this area would certainly be appreciated. Oh yeah, it's OK to use geek-speak, I'm a technician, so I'm used to it

Thanks in advance...

mccoffee · Post by **mccoffee** » Sun Jan 22, 2006 11:25 pm

Bandwith is the highest point of the wave in the fequency. Troughput is the speed it it's self. The bandwith is 512 however that could be a theroectlly limit

A good read though http://www.tcpipguide.com/free/t_PerformanceMeasurementsSpeedBandwidthThroughputand.htm

Post by **YeOldeStonecat** » Mon Jan 23, 2006 7:10 am

Focus on what you see....
Bandwidth of a network device is measured in bits per second, throughtput however, since it's usually done in software, well...software measures transfers using bytes per second. A byte is eight bits. So there's a difference between Bps(Bytes per second) and bps(bits per second).

Steve-O · Post by **Steve-O** » Mon Jan 23, 2006 7:45 pm

Thanks to both of you for your responses. The mini-primer on terminology was somewhat informative, but not really what I was looking for. I am A+ and Network+ certified, so I have the nuts and bolts and acronyms covered. I was looking for a more fleshed out discourse on the two. But again, thanks for taking the time to reply...

mccoffee · Post by **mccoffee** » Mon Jan 23, 2006 8:43 pm

might wait to try cisco's site they might have something more indeapth

trogers · Post by **trogers** » Mon Jan 23, 2006 9:26 pm

If your are looking for thesis studies on this subject, here is a link:

http://www.google.com/u/UCSantaCruz?q=t ... .y=9&sa=Go