Almost There...Second Post

torataka · Post by **torataka** » Sat Sep 28, 2002 6:54 am

All,

Thanks to mnosteele and some experimenting on my own, I am getting close to half-way decent speeds for my 1.5MB ADSL connection. I have to admit that I'm a challenge to optimize as I live in Japan and use NTT's Flet ADSL service, which seems to be limited to a 1454 MTU and 1414 MSS from all my research. Other than that, I'm on WINXP using the built-in PPPoE connection software.

At the bottom of this post are my TCP/IP Analyzer results. Also, which are probably of interest, here are some of my more important CableNut settings:

DefaultReceiveWindow: 51100
DefaultSendWindow:16384
MaxFastTransmit: 51100
GlobalMaxTcpWindowSize: 260176
TcpReceiveSegmentSize: 1480
TcpSendSegmentSize: 1480
TcpWindowSize: 260176

From the TCP/IP Analyzer results, it appears as if RcvWindow at 200ms is close to what I should expect with a 1.5MB ADSL connection, especially since I'm 3500m away from the nearest NTT switching station (unless I'm wrong?). However, in running ping tests, I'm usually around a 400ms average, which makes me concerned about my low download speed at 500ms. Either way, I'd most sincerely appreciate some suggestions for a few last tweaks that could better optimize my current connection settings.

Many thanks in advance, especially to mnosteele for getting me started in the right direction.

torataka

SpeedGuide.net TCP/IP Analyzer
TCP properties for IP = XXX.XXX.XXX.XXX (ohcn-acs1.hi-net.ne.jp)
Browser/OS = Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; 1.22.1 ; .NET CLR 1.0.3705)
Note: Read the FAQ if the above is not your IP address.

TCP options string = 020405860103030201010402

MTU = 1454
MTU is not fully optimized for broadband. Consider increasing your MTU to 1500 for better throughput.

MSS = 1414
Maximum useful data in each packet = 1414, which equals MSS.
MSS is not fully optimized for broadband (although it might work well for slower connections). Consider increasing your MTU value.

Default Receive Window (RWIN) = 260176
RWIN Scaling (RFC1323) = 2 bits
Unscaled Receive Window = 65044
RWIN is a multiple of MSS
Other values for RWIN that might work well with your current MTU/MSS:
520352 (MSS x 46 * scale factor of 8)
130088 (MSS x 46 * scale factor of 2)
65044 (MSS x 46)

bandwidth * delay product:
Your RcvWindow limits you to: 10407.04 kbps (1300.88 KBytes/s) @ 200ms
Your RcvWindow limits you to: 4162.816 kbps (520.352 KBytes/s) @ 500ms

MTU Discovery (RFC1191) = ON

Time to live left = 49 hops
TTL value is ok.

Timestamps (RFC1323) = OFF

Selective Acknowledgements (RFC2018) = ON

IP type of service field (RFC1349)= 01011100
Precedence (priority) = 010 (immediate)
Delay = 1 (low delay)
Throughput = 1 (high throughput)
Reliability = 1 (high reliability)
Cost = 0 (normal cost)

4106928 connections tested since 03.10.2001.

Analyzer version: 1.02 - updated 09.20.2002.

mnosteele52 · Post by **mnosteele52** » Sat Sep 28, 2002 4:20 pm

torataka try the following fix for your MTU from Bob Carrick.

1) Download this file http://www.carricksolutions.com/XP_MTU.reg
2) Right click the file and choose "Merge"
3) Click "Yes"
4) Go to "Start" -> Click on "Run" -> Type in "Regedt32.exe" -> Click "OK"
5) Go to this Reg Key "[HKEY_LOCAL_MACHINE\ SYSTEM\CurrentControlSet\ Services\NdisWan\ Parameters\Protocols\0]"
6) Double click on "Protocol MTU"
7) Click on "Decimal" -> Enter your desired value (I.E.: Anything less then 1480.) Use 1480
8) Click "OK"
9) Done!

Once you get it straigth try the following settings in Cablenut:

DefaultReceiveWindow = 192512
DefaultSendWindow = 16384
DisableAddressSharing = 1
InitialLargeBufferCount = 100
InitialMediumBufferCount = 240
InitialSmallBufferCount = 320
LargeBufferSize = 81920
MaxFastTransmit = 64000
MediumBufferSize = 15040
PriorityBoost = 0
SmallBufferSize = 1280
TransmitWorker = 32
FastSendDatagramThreshold = 4096
EnableFastRouteLookup = 1
EnablePMTUDiscovery = 1
IgnorePushBitsOnReceive = 0
GlobalMaxTcpWindowSize = 37440 or 51840 or 63360
MaxFreeTcbs = 8000
MaxHashTableSize = 16384
MaxNormLookupMemory = 5000000
SackOpts = 1
SynAttackProtect = 1
Tcp1323Opts = 0
TcpLogLevel = 1
TcpMaxDupAcks = 2
TcpMaxHalfOpen = 100
TcpMaxHalfRetried = 80
TcpRecvSegmentSize = 1440
TcpSendSegmentSize = 1440
TcpTimedWaitDelay = 30
TcpUseRFC1122UrgentPointer = 0
TcpWindowSize = 37440 or 51840 or 63360
MaxConnectionsPer1_0Server = 20
MaxConnectionsPerServer = 10
DefaultTTL = 64
DisableUserTOSSetting = 0
TcpMaxDataRetransmissions = 6
DefaultTOSValue = 92

torataka · Post by **torataka** » Sat Sep 28, 2002 7:11 pm

Thanks once again, mnosteele52. Below are my TCPAnalyzer results using 51840 along with the other tweaks you suggested, which seem to give me my best results. With this, I'm getting anywhere from 85-119k/bps on my 1.5MB DSL connection using SpeakEasy. Any other tweaks we can look at?

The only other question I have is why the 25552 gives my a RcvWindow of 10222.08 kbps over the 51840's 2073.6, but the latter, somewhat contradictory to what I believe should happen, seems to give me a better download speed?

Thanks again, mnosteele52, for all your help.

torataka

P.S. I already had the 1480 Registry entry using the Microsoft Q283165 Knowledge Base Article.

SpeedGuide.net TCP/IP Analyzer
TCP properties for IP = XXX.XXX.XXX.XXX (ohcn-acs1.hi-net.ne.jp)
Browser/OS = Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; 1.22.1 ; .NET CLR 1.0.3705)
Note: Read the FAQ if the above is not your IP address.

TCP options string = 020405860101080a000000000000000001010402

MTU = 1454
MTU is not fully optimized for broadband. Consider increasing your MTU to 1500 for better throughput.

MSS = 1414
Maximum useful data in each packet = 1414, which equals MSS.
MSS is not fully optimized for broadband (although it might work well for slower connections). Consider increasing your MTU value.

Default Receive Window (RWIN) = 51840
RWIN Scaling (RFC1323) = 0 bits
Unscaled Receive Window = 51840
For optimum performance, consider changing RWIN to a multiple of MSS.
Other values for RWIN that might work well with your current MTU/MSS:
520352 (MSS x 46 * scale factor of 8)
260176 (MSS x 46 * scale factor of 4)
130088 (MSS x 46 * scale factor of 2)
65044 (MSS x 46)

bandwidth * delay product:
Your RcvWindow limits you to: 2073.6 kbps (259.2 KBytes/s) @ 200ms
Your RcvWindow limits you to: 829.44 kbps (103.68 KBytes/s) @ 500ms

MTU Discovery (RFC1191) = ON

Time to live left = 49 hops
TTL value is ok.

Timestamps (RFC1323) = ON
Note: Timestamps add 12 bytes to the TCP header of each packet, reducing the space available for useful data.

Selective Acknowledgements (RFC2018) = ON

IP type of service field (RFC1349)= 01011100
Precedence (priority) = 010 (immediate)
Delay = 1 (low delay)
Throughput = 1 (high throughput)
Reliability = 1 (high reliability)
Cost = 0 (normal cost)

mnosteele52 · Post by **mnosteele52** » Sat Sep 28, 2002 7:28 pm

Remember all the analyzer tells you is your current TCP/IP settings..... it's not a speed test. Also your MTU is still not correct, did you try the fix I suggested?

torataka · Post by **torataka** » Sat Sep 28, 2002 8:04 pm

Yes, I did the merge trick and 1480 is in there. No matter what I seem to do I can't raise my MTU from 1454. In doing some research on my NTT Flet ADSL connection, it seems as if that's the default MTU used by NTT and I can't find any way to uncap it. Does anyone else visiting this board from Japan have any suggestions?

Thanks again, mnosteele, for taking an active interest in helping me out.

torataka

mnosteele52 · Post by **mnosteele52** » Sat Sep 28, 2002 8:13 pm

If that is the default MTU from your ISP you might not be able to change it. If you have tried everything to change it with no luck then try changing your GlobalMaxTcpWindowSize & TcpWindowSize to be an even multiple of your MSS which is 1414, you might try 36764 or 50904 or 62216.