My 28.8Kbps modem downloads at 83.6Kbps!!!!!!!!

[Whitedog]

Well, I'm not exactally sure about this, but listen to this...

I noticed one day that when surfing on AnandTech forums, my modem download rates are insane! (for a 28.8), but when I go to any other website, it looks normal... So, I did a test.

I loaded up a large thread, disconnected from the net, redialed up, once connected, I hit refresh on the large thread over and over for 5 minutes worth of constant downloading from AnandTech.

Here are the results:
Windows 2000 DUN
Connection Speed: 28,8 Kbps
Duration: 00:04:46
Bytes (not bits) sent: 228,976
Bytes (not bits) recieved: 2,991,226
Compression: 0%
Errors: 0

You do the math!

4:46 = 286 seconds. 2,991,226 / 286 = 10,456 Bytes/sec x 8 = 83.6Kbps
I know this can't be right, but this is everytime I use this site, and no others.. INSANE download rates!

Someone else test this and confirm.

 

[Zeeliv]

Um, in Windows 2000 DUN the time is listed as HH:MM:SS (As in hours:minutes:seconds). So your 00:04:46 is just under 5 minutes, not 286 minutes. I'm not gonna bother scrutinizing the rest of your math...but rest assured if it took you 286 minutes to download just under 3MB, you'd have a much slower connection than 83Kbps

 

[Pariah]

I have no idea where you got those numbers from, and I am even more stunned how you came up with a right answer using the erroneous numbers you did, it may just be a case of wrong unit labels. Anyway, to answer your question, you were downloading basically a pure text file over and over again. HTML can be highly compressed. The download number is an uncompressed number, the compressed number would probably be far smaller. What would posses you to sit there for 5 minutes and reload a page? Try downloading a large file from a large server, the number will be far lower.

 

[Whitedog]

CRAP! Whatever! I meant Seconds dood! So I made a typo.. the math is correct though..

 

[Deeko]

He meant seconds. I don't think he hit refresh on his browser for 5 hours straight

 

[Zeeliv]

I'm sure it was just a typo on his part, he meant to put seconds where he put minutes. I was just screwing around. Dunno about the actual numbers though. I swear I once downloaded a file much faster than should have been possible on a 56K once, even calculated it out afterwards and it just didn't fit

EDIT: see, he replied as I was typing...always happens

 

[Whitedog]

LOL Deeko, no. I didn't.

Parish, if you read, I already said download speeds on other webpages are normal, just on this BBS they are as I stated..

I don't know a lot about this network stuff, and certainly don't know about compressed HTLM, it's just confusing that it says it downloads so much in only 4:46 (minutes! ok? hehe)

 

[Whitedog]

I guess I can understand now, but I don't know why DUN would display the data after uncompressed? I'd think it would be reporting actual Net traffic?

But, what the hell do I know..

 

[Pariah]

Most remotely recent modems are capable of 115kbps compressed dl's. Sometimes NT will erroneously report your connection as 115kbps if your settings are incorrect. Obviously, that number is under ideal conditions, and will never actually be achieved.

 

[dexter333]

One of my friends has downloaded executables and zip files at 96Kbps (sustained for 5 minutes) on a 56K modem. But he can only connect at 26400.


-Dexter

 

[ViRGE]

I'm willing to bet that the AT forums compresses well. It's all text, with a lot of words, so that kind of compression isn't out of the question.

 

[Instigator]

First, in the best situation a standard phone line can only download at 52Kbps (Kilo bits per second). Which translates into about 4.8KBps (Kilo Bytes pers second) to 5.2KBps download speeds. Trust me, you are NOT downloading at 83.6 Kbps. Here are some download speed numbers:

56Kbps = 5.6KBps (Kilo Bytes per second)
Dual Channel ISDN 128Kbps = 15.0KBps
DSL (768Kbps) = 90KBps

It's a nice thought tho.

 

[Instigator]

bump

 

[Remnant2]

Instigator : not necessarily true.

It's been quite a while since my actual phone-line BBS days (remember those?), but most modems use a variety of protocols, for both error-correction and data compression. The modem data rate itself is no doubt 42kbps or less, which is what you'll get on a zip'd file or other similarily uncompressable, but when transferring text, 80kbps certainly isn't unheard of -- the modem has hardware compression, quite limited when compared to, say, pkzip, but it can probably manage a 2x compression ratio on very redundant text. I remember USR boasting many years ago about how the Msomething5 standard could do up to 8-1 compression on text files.

 

[rbV5]

Instigator, WRONG my DSL can download much faster over my standard phone line.

 

[Adul]

Instigator, check your math, last I check 8 bits = 1 Byte.
So

56Kbps = 7 KB/sec
128Kbps = 16 KB
256Kbps = 32 KB
etc...

I have had tweak my modem and sustain downloads of 6 KB/sec Was nice since the file was 100 MB. But that was when I was on dialup.

 

[skriefal]

Adul,
You're forgetting to take into account the bits needed for error correction. You can't just calculate 56/8 = 7 and assume that you'll get 7KB/s downloads. Also, it's 53kbps -- not 56kbps .

Perhaps someone else can comment on how many error correction bits are used, on average, per byte of date transmitted with modern protocols (i.e. v.90, etc).

 

[Loggerman]

83.6 kbps may just be your modem to cpu speed.Sometimes when add the wrong command string to extra string commands all you get is a fake ready(phone companies try this with people that don't know any better).If your getting 115kbps ,then you more than likely are getting a false reading.
Try 56k.com.A BB on nothing but modems.

 

[oldfart]

There are many factors to consider, error correction, compression are just two of them. The modem can do V.42/LAPM hardware compression, and Windows can do STAC software compression. Most things on the web are precompressed such a jpegs, gifs, zip and exe files. You usually don't get a lot of compression improvements. If you were to download a huge text document, you would see it. My experience with modems and downloads is this: in easy very round numbers, you will get about connect speed/10. Your 28.8k connect will get you about 2.8k/sec on a download. A good 56k connect of 50k or so will get you about 5K+ per sec. The way you measured it is highly inaccurate. Go to a close site and download a couple meg file that is zipped. You will see with that 28.8 connect, you will get about 2.8k per sec.

 

[chuckieland]

so complicated

 

[Modus]

OK, here's how it works:

Yes, 8 bits does equal 1 byte, however, modems use a START bit and a STOP bit, meaning they take 10 bits to send a byte. So a 56kbps modem is sending 56000 bits per second, effectively 5600 bytes per second. Now, one kilobyte is not 1000 bytes, it's 1024 bytes. So if we take 53000bps as the maximum receive speed due to FCC regulations on 56k transmissions, our effective transfer rate is no more than 5.176K/s.

So why do we sometimes see higher transmit speeds? Compression -- two layers of it. There's hardware compression done by the ISP's modem before sending you the data, and there's TCP/IP compression done by the server/router at the data source. Anything sent over modern modems, regardless of the data type (zips, text, graphics, whatever) will be compressed automatically. Most large files, such as self-extractable executables (ie SETUP.EXE), zip files (ie DOCS.ZIP), digital media (SHAFT.MP3), or graphics (SHARKY.JPG), are already highly compressed leaving the modem only able to squeeze out an extra 1 or 2%. But large web pages consisting mostly of text (such as certain threads I have participated in) will tend to compress extremely well; even 2-1 or 3-1 is not uncommon.

Modus

 

[Instigator]

Here are some download speed numbers:

56Kbps = 5.6KBps (Kilo Bytes per second)
Dual Channel ISDN 128Kbps = 15.0KBps
DSL (768Kbps) = 90KBps



Sorry, I meant those numbers to be rough estimates of download speeds and not exact numbers. But those numbers are still pretty close. My 56K modem never downloaded at more than 4.5K and that was when I connected at 42K. For my ISDN line I usually download at 15K when having both lines bonded (i.e. 128K).

rbV5,
You are correct. I forgot about ADSL, which uses standard phone lines. Me bad.

 

[WoundedWallet]

The same thing is happening to me, vid my post here.

The compression explanation seems the most reasonable since I don't quite understand where or how the measurement is made.