Question about registry tweak for MTU setting

cholla

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Question about registry tweak for MTU setting

« on: January 08, 2005, 04:48:57 PM »

I have my registry pretty well tweaked for the MTU .I prefer to do this myself instead of using programs.There is a setting that I haven't been able to get any information on.It is located here in a windows 98 se:HKLM/System/CurrentControlSet/Services/VxD/MSTCP/Ndi/ATMDefaults.then on the right screen there is a binary value named MTU. Does anyone know if there is a tweak for this setting or what this setting does? :rolleyes2:


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VanBuren

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Re: Question about registry tweak for MTU setting

« Reply #1 on: January 09, 2005, 03:52:07 AM »

hey cholla and welcome to the forum

check this thread http://testmy.net/forum/index.php?topic=1092.0

there is no need to set MTU

Path MTU detection is enabled by default

check this http://www.dslnuts.com/9xme.shtml

quote "19. PMTUDiscovery - Setting this parameter to 1 (True) causes TCP to attempt to discover the Maximum Transmission Unit (MTU or largest packet size) over the path to a remote machine. By discovering the Path MTU and limiting TCP segments to this size, TCP can eliminate fragmentation at routers along the path which connect networks with different MTUs. Fragmentation adversely affects TCP throughput and network congestion.

Value Type: String Value

Default: 1"

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cholla

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Re: Question about registry tweak for MTU setting

« Reply #2 on: January 09, 2005, 01:31:36 PM »

Thanks VanBuran.I already had the PMTU Discover tweak in my registryset at 1.I had already read the thread & DSL site info .I am on a regular dial-up ISP & I am 28600 ft from the Telco.The MTU tweaks that I have put in my registry have improved my speed even after I added the PMTUDiscovery one.This might be because my MTU is already the right size when the TCP discovers it.This is why I had a question about the tweak I asked about to do a little more fine tuning.This is a download test done today
::::::::::.. Download Stats ..::::::::::
Connection is:: 51 Kbps about 0.1 Mbps (tested with 386 KB)
Download Speed is:: 6 kB/s
Tested From:: http://www.testmy.net/
Bottom Line:: 1 times faster than 56K you can download 1MB in 170.67 second(s)
Validation Link:: http://testmy.net/cgi-bin/get.cgi?Test_ID=DFMLC0UXM
I know this is not much compared to your speed test as I visited your site & signed the guestbook.But it is good for Dial-up at the distance I am from the Telco.My current ISP cannot be pingged I have talked to there techs which are pretty good for ISP techs at least they are not in India & they say this is for security.Here is a way to get an ISP's MTU In My Computer go to Dial-up net/Modem Properties/Options.Select the "Bring up terminal window after dialing" .Then dial your ISP.A black window appears wait till it asks for user&hit enter;then type in your password& hit enter.The MTU should be one of the results reported.This is on a aWindows 98 SE.You may have to try more than once to get this to work even needing to restart other times it works the first time.


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VanBuren

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Re: Question about registry tweak for MTU setting

« Reply #3 on: January 09, 2005, 01:44:06 PM »

oh you was on dial up, then you should try to force 1500 as MTU, if i remember it right default is 576

In cablenut program its very easy, just set your MSS ( maximum segment size ) to 1460

what does the tweaktester say your MTU is?

http://www.dslreports.com/tweaks

i will check my guest book then

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cholla

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Re: Question about registry tweak for MTU setting

« Reply #4 on: January 09, 2005, 02:58:46 PM »

Thanks again VanBuran I already am doing this as far as I can tell.One of the tweaks for this is at HKLM/System/CurrentControlSet/Services/Class/Net/000/Ndi/Params/IMPTU/enum.The 000 is your ISP. The only settings I have here now are 2 string values Default & 1524 Automatic .The 1524 is the MTU value I got from the terminal window in my last post. Here is the usual disclaimer Don't mess with your registry without a backup. :)Cholla


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cholla

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Re: Question about registry tweak for MTU setting

« Reply #5 on: January 09, 2005, 03:11:23 PM »

VanBuran this is the URL of my test from broadband.If you have dial-up you have to trick this test to get the results since it has no dial-up in its list.I use the ISDN setting & 128k these are not correct but the only way for me to get the results.So here they are: http://ttester.broadbandreports.com/tweak/block:3627a05?service=isdn&speed=128&os=win98SE&via=normal I hope this works otherwise I will do the test again & cut & paste it. THANKS Cholla


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VanBuren

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Re: Question about registry tweak for MTU setting

« Reply #6 on: January 09, 2005, 03:19:45 PM »

looking good

only windows scaling dont need to be enabled, but it has no effect since your scaling is 0

Window Scaling: 0
RFC1323 Window Scaling: ON

this is correct, so you dont need to change MTU anymore
Max packet sent (MTU): 1500
Max packet recd (MTU): 1500

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