10/100 network-expected speeds.

kendalle01 · ‎10-26-2005

Users of FTP continually complain because is often takes time to downoad a file from the LAN. I tested myself by create a 1 GB file on a FreeBSD machine and then downloading it.

dd if=/dev/zero bs=1024 count=1024 of=/home/erick/some.file

I copied over several of these and downloaded them from a desktop:

ftp> get some.file

200 PORT command successful. Consider using PASV.

150 Opening BINARY mode data connection for some.file (1048576 bytes).

226 File send OK.

ftp: 1048576 bytes received in 21.48Seconds 48.81Kbytes/sec.

ftp> prompt off

Interactive mode Off .

ftp> mget some*

200 Switching to Binary mode.

200 PORT command successful. Consider using PASV.

150 Opening BINARY mode data connection for some.file (1048576 bytes).

226 File send OK.

ftp: 1048576 bytes received in 22.92Seconds 45.75Kbytes/sec.

200 PORT command successful. Consider using PASV.

150 Opening BINARY mode data connection for some1.file (1048576 bytes).

226 File send OK.

ftp: 1048576 bytes received in 22.91Seconds 45.78Kbytes/sec.

200 PORT command successful. Consider using PASV.

150 Opening BINARY mode data connection for some2.file (1048576 bytes).

226 File send OK.

ftp: 1048576 bytes received in 22.89Seconds 45.81Kbytes/sec.

200 PORT command successful. Consider using PASV.

150 Opening BINARY mode data connection for some3.file (1048576 bytes).

226 File send OK.

ftp: 1048576 bytes received in 22.92Seconds 45.75Kbytes/sec.

200 PORT command successful. Consider using PASV.

150 Opening BINARY mode data connection for some4.file (1048576 bytes).

226 File send OK.

ftp: 1048576 bytes received in 22.89Seconds 45.81Kbytes/sec.

200 PORT command successful. Consider using PASV.

150 Opening BINARY mode data connection for some5.file (1048576 bytes).

226 File send OK.

ftp: 1048576 bytes received in 22.92Seconds 45.75Kbytes/sec.

200 PORT command successful. Consider using PASV.

150 Opening BINARY mode data connection for some6.file (1048576 bytes).

226 File send OK.

ftp: 1048576 bytes received in 22.92Seconds 45.75Kbytes/sec.

200 PORT command successful. Consider using PASV.

150 Opening BINARY mode data connection for some7.file (1048576 bytes).

226 File send OK.

ftp: 1048576 bytes received in 22.91Seconds 45.78Kbytes/sec.

200 PORT command successful. Consider using PASV.

150 Opening BINARY mode data connection for some8.file (1048576 bytes).

226 File send OK.

ftp: 1048576 bytes received in 22.91Seconds 45.78Kbytes/sec.

ftp>

My math skill stink :( I'd like to know how to convert from the bit speed (as in 100 Mbits) into byte speed (Kbytes) so I can better understand when things are or are not slow?

Brandon Buffin · ‎10-26-2005

1 byte = 8 bits

1 Kbyte = 1000 bytes

1 Mbit = 1000 Kbit or 125 byte

100 Mbit = 100000 Kbit or 100 Million Bits or 12,500,000 bytes

In your example, 45.78 Kbytes/sec = 366,240 bits/sec

Hope this helps.

Brandon

sbrozius · ‎10-28-2005

Not meant to confuse things, but as far as I know the list should be this:

1 byte = 8 bits

1 Kbyte = 1024 bits = 8192 bits

1 Mbyte = 1024 Kbyte = 1048576 bytes = 8388608 bits

100 Mbyte = 102400 Kbyte = 104857600 bytes = 838860800 bits

45.78 Kbytes/sec translates to 45.78 * 1024 = 46878.72 bytes/sec which translates to 46878.72 * 8 = 375029.76 bits/sec

aravindhs · ‎10-28-2005

I'm afraid the above calculation is incorrect.

Ikilobits =1000 bits and not 1024 bits because you are not considering 2^10 bits but 10^3 instead- this it the standard.

Lets take an example from the ftp output :

============================================

ftp> get some.file

200 PORT command successful. Consider using PASV.

150 Opening BINARY mode data connection for some.file (1048576 bytes).

226 File send OK.

ftp: 1048576 bytes received in 21.48Seconds 48.81Kbytes/sec.

============================================

1048576 bytes == 1048576 * 8 bits == 8388608 bits (in 21.48 seconds)

Hence , in one second = 8388608 / 21.48 ==> 390531.0 bits in 1 second

390531.0 bits in 1 second == 390531.0/8 == 48816.375 bytes in 1 second

48816.375 / 1000 = 48.81 Kilo bytes per second

HOPE THAT HELPS

Cheers

kendalle01 · ‎10-28-2005

Yes, all the responses were helpful. I was happy to see that I'm not the only one who gets confused by what appears to be a simple question. If I'm only doing some 400,000 bits in 1 second then I'm not using 1/2 the 1,000,000 bit pipe or a 100 Mbit connection. I know there's overhead but isn't my ftp speed still fairly slow?