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Question on receive window


cak46

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hope someone may have info on this: 

I've been monkeying around with many of the tweaks for speeding up my connection but have found that my rwin stays static at 65535.

Have checked this at a number of different reporting sites but my receive buffer remains the same, no matter what I've changed it to.  Could this be a function of Adelphia'ssystem or some other reason?  I've been to the speedguide.net and did the recommended update for this problem.

rcvwindow is presently set at 1027840 

This info is from the improved ORNL web100 site

http://whisper.cs.utk.edu:7123/

TCP/Web100 bandwidth test v4.12

click START to begin

running 10s outbound test...  257 Kbs outbound

running 10s inbound test...  4375 Kbs inbound

    Web100 Inbound Summary:

Packets to your host:  3800  of size 1460 bytes

average RTT: 110.0 ms  minimum RTT: 60.0 ms

Maximum Expected Bandwidth: 8 Mbs

Inbound limits:

    congestion 10% server: 0% your host: 89%

Good Data Stream--No retransmits!

Your host's receive buffer: 65535 bytes

Server's send buffer: 95681100 bytes

            receive buffer: 65535 bytes

  Buffer sizes are very important in determining

  network performance.  Larger buffer sizes can

  help increase thruput.  If your buffer is smaller

  than the remote host, you should investigate

  increasing your socket buffer sizes.

    Web100 reports Tweakable Settings as:

RFC 2018 Selective Acknowledgment: ON

RFC 1323 Time Stamping: OFF

RFC 1323 Window Scaling: OFF

click START to re-test

Anyone have any ideas on this?

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hey cak46 : I will leave most of the help to Van Buren but you have to enable window scaling to use a larger RWIN

than 65535.If you have installed Cablenut  this setting is TCP1323Opts set to 1 .Then put the larger RWIN you want to use.I like to use speedguide.net  tcp analyzer to show you that the scaling is working & suggest RWIN based on a multiple of your MSS. It will show an unscaled RWIN of like 64240 & the times scaled.  Cholla

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I'm running win98 SE.  I've tried both with scaling and timestamps in assorted configurations, but regardless it still comes back as 65535.  The setting I presently have for rwin is 1027840.  I've tried many different settings, even lower than the 65535, but it still remains the same according to different test sites.  Here are the specifics form web100 from ornl:

WEB100 Kernel Variables:

CongestionSignals: 1

CurCwnd: 14600

CurMSS: 1460

CurSsthresh: 32120

DupAcksIn: 351

LimCwnd: 95681100

LimRwin: 65355

MaxCwnd: 67160

MaxRTT: 160

MaxRwinRcvd: 65535

MaxRwinSent: 5840

MaxSsthresh: 32120

MinRTT: 50

OtherReductions: 5

PktsOut: 3791

PktsRetrans: 1

RetranThresh: 3

SACKEnabled: 3

SACKsRcvd: 57

SampleRTT: 70

SendStall: 0

SmoothedRTT: 100

SndLimTimeRwin: 8923536

SndLimTimeCwnd: 1505962

SndLimTimeSender: 2726

Timeouts: 0

WinScaleRcvd: 0

WinScaleSent: 0

DupAcksOut: 0

DataPktsIn: 0

Timeouts: 0

CongestionSignals: 1

MinRTT: 50

MaxRwinSent: 5840

MaxRwinRcvd: 65535

PktsRetrans: 1

SmoothedRTT: 100

PktsOut: 3791

My thought is that this is happening at an op sys or Adelphia level (could be a way to limit bandwidth usage).  Whenever I try to set my router, Linksys BEFSX41, to 1500 mtu my connection goes south.    The analyzer at speedguide shows the same RWIN 65535. 

Thanks for the help in advance  cak46

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