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Leopard is setting RWIN too large!!!

19923 Views 68 Replies Latest reply: Apr 17, 2008 2:51 PM by mbpjunkie RSS
  • mkbilbo Calculating status...
    Currently Being Moderated
    Nov 16, 2007 9:19 AM (in response to Scott Micciche)
    Just thought I'd say, one *Nix geek to another, I'd recommend against recommending (as it were).

    Over here:

    http://www.apple.com/macosx/technology/unix.html

    Apple talks about "Self-Tuning TCP". I'm not sure what they're up to but I did my usual tweaking with sysctl that I'd done on Tiger and something went Very Wrong.

    I don't think I'd want to advise people to mess with sysctl. Not until somebody figures out what Leopard is up to.
    iMac 20" Intel Duo 2.33GHz, Mac OS X (10.5)
  • mkbilbo Level 1 Level 1 (0 points)
    Currently Being Moderated
    Nov 16, 2007 9:22 AM (in response to Elliot Roth)
    zaxcom wrote:
    Just wanted to update folks and say that 10.5.1 did NOT fix this problem. I still must set my sockets to 0, or my receive window still gets way to large.


    I gotta jump in here to dissent. Apple is doing something dynamic with those windows and I caused a Very Bad Thing to happen doing my usual sysctl tweaks. I also have to say you probably should not trust the numbers coming back from "speed test" sites for your receive windows and such. Nor what sysctl reports. I haven't put the effort into pinning down what Apple is doing but they have some kind of "self-tuning" in Leopard.

    http://www.apple.com/macosx/technology/unix.html

    See: "Self-Tuning TCP".

    I made at least one change Leopard did not handle well (no, I don't know which but it all worked fine on Tiger) and ended up having to re-install. It was not pretty.
    iMac 20" Intel Duo 2.33GHz, Mac OS X (10.5)
  • Rod Ernouf Level 1 Level 1 (115 points)
    Currently Being Moderated
    Nov 17, 2007 1:19 PM (in response to Elliot Roth)
    The 10.5.1 update fixed the wireless connectivity problem for me. I renamed my sysctl.conf to sysctl.conf.bak.
    PowerBook G4, Mac OS X (10.5), 867mhz 1gb SDRAM
  • laurynsausage Level 1 Level 1 (0 points)
    Currently Being Moderated
    Jan 20, 2008 6:46 AM (in response to Rod Ernouf)
    Hi
    I just found this thread and wondered if anyone can help me tweak my internet settings?? I live right next to my exxchange and my ISP stats I should be getting about 7500.00Kbps, but the highest I have ever had is 6049.58 Kbps 343.45 Kbps.

    Usually is it pretty constant between 3000.00 - 5000.00Kbps


    Does anyone have any ideas on the setting I can change? Here are my current settings from speedguide.net

    « SpeedGuide.net TCP Analyzer Results »
    Tested on: 01.20.2008 09:45
    IP address: 81.158.xxx.xx

    TCP options string: 020405b4010303030101080a380f48ae0000000004020000
    MSS: 1460
    MTU: 1500
    TCP Window: 454672 (NOT multiple of MSS)
    RWIN Scaling: 3
    Unscaled RWIN : 56834
    Reccomended RWINs: 64240, 128480, 256960, 513920
    BDP limit (200ms): 18187kbps (2273KBytes/s)
    BDP limit (500ms): 7275kbps (909KBytes/s)
    MTU Discovery: ON
    TTL: 43
    Timestamps: ON
    SACKs: ON
    IP ToS: 00000000 (0)



    Many thanks in advance.
    mini mac using Airport, Mac OS X (10.5.1), 1.66GHz Intel Core Duo - 2 GB
  • DVEous Calculating status...
    Currently Being Moderated
    Jan 31, 2008 11:16 PM (in response to Scott Micciche)
    This is the result I got on speedguide.net TCP Analyzer. I'm new to the Mac world and have no idea if this is the right or wrong settings. I need someone to tell me exactly how to change these settings. I'm on Comcast with a paid speed of 6mbps down and 384kbps up. I'm only getting 4.1mbps down on average and about 356kbps up. Does this look like it's a fixable issue? Thanks for any help you can provide.

    « SpeedGuide.net TCP Analyzer Results »
    Tested on: 02.01.2008 02:07
    IP address: 71.227.xxx.xxx

    TCP options string: 020405b4010303030101080a3652c5970000000004020000
    MSS: 1460
    MTU: 1500
    TCP Window: 524280 (NOT multiple of MSS)
    RWIN Scaling: 3
    Unscaled RWIN : 65535
    Reccomended RWINs: 64240, 128480, 256960, 513920
    BDP limit (200ms): 20971kbps (2621KBytes/s)
    BDP limit (500ms): 8388kbps (1049KBytes/s)
    MTU Discovery: ON
    TTL: 43
    Timestamps: ON
    SACKs: ON
    IP ToS: 00100000 (32)
    Precedence: 001 (priority)
    Delay: 0 (normal delay)
    Throughput: 0 (normal throughput)
    Reliability: 0 (normal reliability)
    Cost: 0 (normal cost)
    Check bit: 0 (correct)
    DiffServ: CS1 001000 (8) - class 1 (RFC 2474). Similar forwarding behavior to the ToS Precedence field.
    iMac 20" 2.4G Intel Core 2 Duo, 4GB RAM, Mac OS X (10.5.1)
  • s_w_i_t_t_e_r_s Calculating status...
    Currently Being Moderated
    Apr 11, 2008 8:08 AM (in response to DVEous)
    I made these changes and they seemed to help with speed. However, I'm having a very strange problem now with web browsing and wonder if it may not be connected?

    I frequently get a blank white screen when I type in a URL that I know is active and working. Or, for example, last night I was working on my WordPress blog and anytime I'd make a change to the configuration and it tried to redirect me to the control panel (which has always worked in the past) I would get a blank white screen instead.

    This only happens with some websites, and even some URLs within a certain website. It happens with both Safari and Camino. I cannot for the life of me figure it out, but I never had this problem before making the changes suggested in this thread.

    What do you think?
    Mac Pro 2.8 (Early '08), Mac OS X (10.5.2), 10 GB RAM, 74GB 10k Raptor, 2x 750GB RAID, 23" ACD
  • Bill Walsh Calculating status...
    Currently Being Moderated
    Apr 14, 2008 5:08 PM (in response to Scott Micciche)
    Ahhh. *Thank you!* You have just saved my sanity.
    MacBook Pro, Mac OS X (10.5.2)
  • mbpjunkie Calculating status...
    Currently Being Moderated
    Apr 17, 2008 2:22 PM (in response to Bill Walsh)
    How do you guys keep the settings after a reboot? I have created a /etc/sysctl.conf & a /etc/sysctl file with my input, but even with these files created and in place... after a reboot the settings always go back to default. It's like the OS doesn't seem to care about the changed files.

    BTW- I'm using Tiger 10.4.11 - I have manually entered all my settings after each reboot, since they don't stay. How did you guys get your settings to stay?

    « SpeedGuide.net TCP Analyzer Results »
    TCP options string: 020405b4010303000101080a44ffdc2f0000000004020000
    MSS: 1460
    MTU: 1500
    TCP Window: 65535 (NOT multiple of MSS)
    RWIN Scaling: 0
    Unscaled RWIN : 65535
    Reccomended RWINs: 64240, 128480, 256960, 513920
    *BDP limit (200ms): 2621kbps (328KBytes/s)*
    *BDP limit (500ms): 1049kbps (131KBytes/s)* --- RWIN: 65535
    MTU Discovery: ON
    TTL: 51
    Timestamps: ON
    SACKs: ON
    IP ToS: 00000000 (0)

    « SpeedGuide.net TCP Analyzer Results »
    TCP options string: 020405b4010303020101080a13c9a1df0000000004020000
    MSS: 1460
    MTU: 1500
    TCP Window: 201272 (NOT multiple of MSS)
    RWIN Scaling: 2
    Unscaled RWIN : 50318
    Reccomended RWINs: 64240, 128480, 256960, 513920
    *BDP limit (200ms): 8051kbps (1006KBytes/s)*
    *BDP limit (500ms): 3220kbps (403KBytes/s)* -- RWIN: 200200
    MTU Discovery: ON
    TTL: 51
    Timestamps: ON
    SACKs: ON
    IP ToS: 00000000 (0)
    MacBook Pro 15" 2.2ghz C2D, Mac OS X (10.4.11), 60GB OSX/60GB WinXP partition
  • mbpjunkie Level 1 Level 1 (35 points)
    Currently Being Moderated
    Apr 17, 2008 2:51 PM (in response to mbpjunkie)
    I might just have to create a script. How do I make a script that can accomplish this task for me when OSX starts?
    MacBook Pro 15" 2.2ghz C2D, Mac OS X (10.4.11), 60GB OSX/60GB WinXP partition
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