On Fri 21 Sep 2001 01:16, Breathnach, Proinnsias (Dublin) wrote:
> figure 48000bits per second on a good connection
> 48000 / 8 = 6000 bytes per second
Not quite. Dialup modems are asynchronous, which means that each byte
is padded out with start and stop bits, and usually parity...
typically taking each "byte" to 11 transmitted bits.
48000kb/s therefore equates to only 4.2kB/s... and there's still the
overhead of error-correction, retransmission etc.
Async modems are shite, basically. I'm still on Surf NoLimits, but I
don't think I've ever been able to get a connection faster than
26400... roll on Tiscali's satellite network.
>> In particular, while fiddling the deflate/bsdcomp options got a bit
>> of an improvement, it looks like compressed or encrypted traffic is
>> stuck at about 4 KB/sec, does that match other people's experience?
Yeah. You won't gain much in the PPP compression protocols, because
most high-speed analogue asynch modems already do run-time data
compression. Compression is all about removing redundancy; if the PPP
drivers have already stripped out redundancy in the data, then the
modem's not going to be able to improve on it much.
Colm
--
Colm Buckley : Systems Architect @ NewWorld Commerce
Business: +353 1 4334334 / colm at nwcgroup.com / http://www.nwcgroup.com/
Personal: +353 87 2469146 / colm at tuatha.org / http://www.tuatha.org/~colm/
If you think nobody cares about you, try missing a couple of payments.
Maintained by the ILUG website team. The aim of Linux.ie is to
support and help commercial and private users of Linux in Ireland. You can
display ILUG news in your own webpages, read backend
information to find out how. Networking services kindly provided by HEAnet, server kindly donated by
Dell. Linux is a trademark of Linus Torvalds,
used with permission. No penguins were harmed in the production or maintenance
of this highly praised website. Looking for the
Indian Linux Users' Group? Try here. If you've read all this and aren't a lawyer: you should be!
