Here's On For YOU!

[grandslammer]

Okay. I went to Tweak 3D to get as much information as I could to "optimize" my cable modem.

Registry tweaksmostly regardingthe MTU,MSS, MaxRecWindow, TTL, etc. I pinged my isp to find the "optimum" setting for the MTU. Did this by opening a DOS window and typing

ping -f -l packet size (I used 1452) isp (charter.net)

Thought I was really doing something here.

Now, I'm on my sister-in-law's machine, and thought I'd do her a favor and optimize her system.

Here 'ya go -

my first settings on her machine were:

MTU 1452
MSS 1412 (MTU-40)
DefaultRcvWindow 459360
TTL 128
this averaged around 45KB/sec

Now, it's set (More for phone line modems) at:

MTU 548
MSS 508
DefaultRcvWindow 459740(even multiple of MSS)
TTL128

and at this MTU setting, it is now running at around 46-48KB/sec, a little faster!

Hmmmm why did I waste my time "optimizing" these values only to find bupkiss?

Any input here?

Mike P.

[grandslammer]

Tried both settings again. I can't figure this out.

Am I missing something here? How does an MTU of approx 1/3 the size give me a faster throughput?

Thanks...

Mike P.

[This message has been edited by grandslammer (edited 12-29-1999).]

[reddog4629]

Most isp's use MTU=1500. MTU-28bytes is what the ping will show(1472)so set it for 1500(windows default).
Are u using dial-up? Then try MTU=576(most common).
MSS(Maximum Segment Size)=MTU(Maximum Transmission Unit)- 40 bytes(Header Info.)
That's the upstream stuff. Now for the downstream stuff (RWIN). Most suggest setting
RWIN(Receive Window) to an integer multiple of mss. I.e. if your mss is 536(576-40) try
rwin=2680 (MSS x 5) or rwin=2144(mss x 4) or
rwin=3216(mss x 6). Just use a whole number multiplier for rwin.When i used dial-up(got cable now) I used MTU=576 and RWIN=2680.
U could use a prog. called TweakDun and it will do all that for u. http://hotfiles.zdnet.com/cgi-bin/texis/swlib/hotfiles/info.html?fcode=000LUV

[netsurfer]

The MTU of 576 helps mostly for regular dialup modems, but I think having the RWIN value at so high really makes the difference... Lower MTU for cable supposedly gives you lower packetloss, and better ping for online gaming since bandwidth isn't an issue.
http://www.speedguide.net/ - more info on tweaking your cable modem.

My RWIN is at 373630 (something like that), and I get downloads of around 80-250kb/sec. (MediaOne RoadRunner in LA)

[grandslammer]

Well, on my latest ping, I got 1421. I don't know what's up here. But, that was (1421) the highest successfully returned ping I could get without loss...

Hmmm... So, here I am... Maybe it's lineproblems, huh? Don't know. When I get my own machine back, I'll se if it's the same deal at my house too.

Thanks for all input, and I guess I'll just continue to run at the highest ping I can.

Mike P.

[grandslammer]

Oh yeah, which entry is better to use. DefaultRcvWindow, or RCWIN? I found the fromer in my registry, but not the latter. Do both mean the same thing, and are the found in the same area of registry? (MSTCP?)

Thanks Again,

Mike