Tweaking a non-capped connection

[Aciliv]

This is more than just an addendum to my previous post, as I will show in the following. Due to more than one issue with SP3, I decided to do a clean format and re-install of Win2kPro, and thus here I am, wanting to tweak, but TCP/IP Optimizer doesn't work on my box (When I tweak to the max, it cuts my MaxMTU down to 1420, MSS to 1380, and my TCP Receive window somehow becomes 1376). So anyway, I downloaded Cablenut, and managed to get it to reset all my settings to the default. However, I want/need more. Here are the settings of the network I'm on, and I would appreciate it if optimal TCP/IP registry settings were provided. I'm on campus, and the entire campus is wired with 100mb/s switches. The backbone is a dedicated OC-3 fiber line. I have, in the past, gotten 35000kbps up and down, but not consistently. I would appreciate it if someone could help me figure out optimal settings to best take advantage of the bandwidth available to me. Thanks.

[MadDoctor]

Why do you want so much speed? I can understand running a porno site or bragging rights (my favorite) but you're on campus.

[Aciliv]

Simply because I'm like most computer geeks, I want the best performance out of my box that is possible. I'm not planning on running anything large except for a small ftp for some friends, but still, once somebody here helps me through the tweaking of my TCP/IP stuff, I can help others.

[MadDoctor]

You're probably behind a proxy if you're on campus.

[Ka|ibur]

Originally posted by MadDoctor
Why do you want so much speed? I can understand running a porno site or bragging rights (my favorite) but you're on campus.

LOL
Mad Doctah and his porno...

[Mohan-san]

Originally posted by Ka|ibur
LOL
Mad Doctah and his porno...

:shudder:

[MadDoctor]

That's right. I'm a guy... and I look at porn. Animal porn that is.

[Mohan-san]

Originally posted by MadDoctor
That's right. I'm a guy... and I look at porn. Animal porn that is.

Phew, and I thought you were looking at normal porn for a second there.

[Aciliv]

I'm not behind a proxy, and besides, what would that have to do with anything about my ReceiveWindow sizes? I suppose I should've approached you as a supplicant, passing myself off as a newbie, rather than a knowledgeable, but inexperienced with TCP/IP registry, tech person. I haven't gotten a single piece of advice that I could use yet. I'm trying to get some information, and you people are like, "Check your MTU, but you're behind a proxy".

[Lobo]

In IE, go to Tools, internet options, connection tab at top, LAN settings at bottom, nothing should be checked in this box, NOTHING, No auto detect, no proxy, no automatic configuration script, NOTHING, REBOOT

[mnosteele52]

Could you please post a TCP/IP Analyzer test result, also please read the Help & Tips link in my signature and try the fixes for your MTU. Also do a few speed tests from Speakeasy (in my signature) and post your average speeds so I can get an idea where things are so I can recommend some settings for you.

[Aciliv]

TCP options string = 0204056401010402

MTU = 1420
MTU is not fully optimized for broadband. Consider increasing your MTU to 1500 for better throughput.

MSS = 1380
Maximum useful data in each packet = 1380, 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) = 1380
RWIN Scaling (RFC1323) = 0 bits
Unscaled Receive Window = 1380
RWIN is a multiple of MSS
Other values for RWIN that might work well with your current MTU/MSS:
507840 (MSS x 46 * scale factor of 8)
253920 (MSS x 46 * scale factor of 4)
126960 (MSS x 46 * scale factor of 2)
63480 (MSS x 46)

bandwidth * delay product:
Your RcvWindow limits you to: 55.2 kbps (6.9 KBytes/s) @ 200ms
Your RcvWindow limits you to: 22.08 kbps (2.76 KBytes/s) @ 500ms
Consider increasing your RWIN value to optimize TCP/IP for broadband.

MTU Discovery (RFC1191) = ON

Time to live left = 36 hops
TTL value is ok.

Timestamps (RFC1323) = OFF

Selective Acknowledgements (RFC2018) = ON

IP type of service field (RFC1349)= 00000000


5 from wdc.speakeasy.net:
2002-09-03 19:37:58 EST: 3688 / 15957
2002-09-03 19:38:19 EST: 4090 / 4569
2002-09-03 19:38:38 EST: 4991 / 3048
2002-09-03 19:38:59 EST: 4339 / 2976
2002-09-03 19:39:26 EST: 2540 / 4464

5 from nyc.speakeasy.net
2002-09-03 19:40:15 EST: 4248 / 2232
2002-09-03 19:40:46 EST: 3737 / 3338
2002-09-03 19:41:10 EST: 1946 / 3621
2002-09-03 19:41:33 EST: 3670 / -4129 [apparently my upstream went negative]
2002-09-03 19:42:25 EST: 2444 / 897

The only speedtest that I recorded on dslreports is 27988/29702, but both my upstream and downstream I've seen @ 35000. Last year, with an older comp, on 10mb/s hubs, my speedtests were reliably 8000/8000

Referring to MTU fixes, I open up regedit, look at my registry, and I'm not seeing any of the \Classes\Net folders, nor \ICSharing. Therefore, I'm not sure how I could edit my MTU.

[Lobo]

Click on change MTU in sig

[Aciliv]

Hm, according to the registry, my MTU is already 1500.

[mnosteele52]

Tell you what try a DSLReports Tweak test and see what it says your settings are, sometimes the TCP/IP Analyzer shows the wrong values. Also look in your registry under:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters

and see what it says TcpReceiveWindow is.

[Lobo]

Whose speed program you have installed

If Cablenut:

TcpRecvSegmentSize = 1460
TcpSendSegmentSize = 1460


Save to registry at bottom and reboot

[Aciliv]

Receive Window (RWIN): 64240
Window Scaling: off
Path MTU Discovery: ON
RFC1323 Window Scaling: OFF
RFC1323 Time Stamping: OFF
Selective Acks: ON
MSS requested: 1380
TTL: (less any hops behind firewall) 53
TTL remaining: 37

And I don't have TCPReceiveWindow, but I do have TCPWindowSize, which is 64240

[Aciliv]

I have both the Optimizer and Cablenut installed, I tried tweaking my Optimizer, setting it to Extreme Optimal (which worked last year), and that flipped out the Analyzer, as it reported back a TCPReceiveWindow size of 1376. Then I used Cablenut, and I think I reset everything to default, so it awaits any and all tweaks.

[Aciliv]

More updates, according to Cablenut:

These are my current installed settings.

LargeBufferSize=8192
MediumBufferSize=3008
SmallBufferSize=256
EnablePMTUDiscovery=1
SackOpts=1
TCP1323Opts=0
TCPMaxDupAcks=2
TCPUseRFC1122UrgentPointer=0
TCPWindowSize=64240
MaxConnectionsPer1_0Server=4
MaxConnectionsPerServer=6
DefaultTTL=48

[Aciliv]

Did the 1460 Rcv/Send Windows, rebooted

wdc
2002-09-03 20:13:44 EST: 7634 / 2630
nyc
2002-09-03 20:14:40 EST: 2328 / -3521

Apparently it likes giving me negative numbers.