Leopard is setting RWIN too large!!!

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.

The 10.5.1 update fixed the wireless connectivity problem for me. I renamed my sysctl.conf to sysctl.conf.bak.

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.

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.

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?

Ahhh. *Thank you!* You have just saved my sanity.

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)

I might just have to create a script. How do I make a script that can accomplish this task for me when OSX starts?