Optimizing 56K Dialup for all OS's

C

catachresis

1
Speedguide.net guide:

http://forums.speedguide.net/showthread.php?threadid=68127

I've done it a couple of times on my Windows 2000 system, and it's greatly improved dialup (at least as far as it can go). In addition, all tweaks are free so you can forget buying an internet accelerator.

NOTE: I've corresponded with the author on a confusing point. For XP and Win2k installation, his guide indicates that you install and cofigure 1) Cablenut and then 2) TCP Optimizer. Do not install TCP Optimizer. It doesn't configure entirely correctly on XP and Win2k. Moreover, Cablenut completes all the settings that the other program would.
 
L

LTR12101B

1
I've always been loyal to EasyMTU for MTU setting
http://easymtu.tripod.com/easymtu/
- Benchmark to several sites, particularly remote ones, or just do (with the MTU set large) a large non-fragmenting ping ( -f ).
If your ISP supports large packets on dialup, but your most wanted paths don't, then a fixed standard 576 is likely to work better - autodetect has some overhead, and may not always be accurate.

For RWIN, I've alway favoured DSLREPORTS, but everyone likes their own sites and tools - there is also a "by hand" rule for RWIN....

Take a distant (but not disgracefully slow) site, take the ping time (average or max ... max is more aggressive) and multiply by 1.5 and by your maximum throughput in bytes/sec (for cable/DSL, this is bits/sec / 8, for dialup, you may like to add a 2x fudge factor for modem compression), and then round that figure to a multiple of 2x MSS (MTU-40) .

RWIN too low, the pipe keeps emptying and you get low throughput (this may be one reason for seeing large gains from a multithreading downloader).

RWIN too high, and you tend to aggravate packet loss, slow the recovery, and have poorer response during multiple sessions.

Bigger RWIN helps fast but delayed links - and if you use satellite, you REALLY have to pay attention to RWIN.
 
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