bandwidth numbers?

Question

this has probably been asked a million times, but why do ISP's say they provide 1Mbps (for example) connections, if the connection only gets you a max speed of a couple hundred Kbps down and even less up? i might understand it if its DSL, but even with DSL they can cap you if you live close to the office, probably because the ISP is communist. and why is uploading always slower than downloading?

Answer 1

Most of the times questions like this one are asked by people not seeing the difference between Mbps and MBps. Yes, case is important.

1 Mbps equals 1000 Kbps (not 1024 !!!) equals 1,000,000 bps (not 1,048,576 !!!).
There are 8 b(its) in 1 B(yte). You get 125,000 bytes per second. Windows weenies think 1 kilobyte is 1024 bytes, so they think they get 122 KBps or even 119 KBps.

There is also the case of protocol overhead. Data is moved inside TCP packets, which are transported inside IP packets, which are transported in ethernet frames, or ATM cells, or whatever other protocol. Providers may compensate you for the carrier protocol (such as DSL overhead) but not for IP and TCP overhead; that's your fault thus your cost.

If one direction of the link is saturated, the other way will suffer. This has to do with acknowledgements not being transmitted as soon as could be. If you saturate your uplink, you will get less data downloaded per time interval. Yet another reason to clean your PC and remove that spam bot from it: not only do others suffer, but you are also hurting yourself.

Last but not least: maybe your line is capable of transporting "x" bytes per second, but it needs not be the bottleneck. Perhaps something else on the internet, such as the server you're getting your data from, is slowing things down.

Answer 2

There's quite a bit of overhead in ADSL, so a 1Mb line will get you about 800Kbps at most, but on top of that the speed of DSL drops as you move further away from the exchange. To achieve the full speed you need to be within a few 100 metres of the equipment in your local telephone exchange, if you go out to 8 miles from the exchange, you'll get 100 or 200 kbps at most.

Uploading is slower than downloading because ADSL (the kind of DSL they sell to residential users) is designed that way so it's cheaper for the ISP. There is another version of DSL, SDSL, which is sold to businesses, which uploads and downloads at the same speed.

Answer 3

The ISP offers connections of various types and speeds based usually on location. If you purchase a 1MB connection, they are pushing a 1MB connection to your computer. This doesn't mean that you will get full 1MB of throughput on your end. If you are far away from the switching station, attenuation or resisance in the lines can slow your connetion down. Also, network congestion and just the genral mechanisms of ethernet based networks consume a considerable amount of throughput. Also, the reason your upload is slower than download is because you have what is known as ADSL or asychronous digital subscriber line connection. This means that the upload and download speed aren't the same and the uplaod is always slower on these connections. SDSL is synchronous both ways but is much more expensive.

Answer 4

its not really the number eg 1 or 4 or 10mb.. is the letters after it mbps, so if you have 1mb thats equal to 1024kbps b=bytes
and there is 8 bites to a byte.

so if you have 1mb connection your max download speed is
1024 devide by 8 = 128kbps.
this is the same for any speed
eg 2mb is 2048 = 256kbps
4= 512kbps
10=1024kbps.
etc etc..

Answer 5

anything but communist.....money - money - money. For the same reason the post office charges you more for some envelopes than others based on the size and weight although shipping and handling those larger envelopes can't be justified by the increased costs of handling the larger size envelopes.