TCP Window Size

Tailgunner9 · Post by **Tailgunner9** » Sat Mar 27, 2004 8:48 am

Mr. Coffee, Installed the new SP2 RC1 and it has changed window size to 64240 from what I have it set at 63888. It still shows it as 63888 where I have always manualy set it in the registry. But the TCP/IP Analyzer shows it as 64240. Has the SP2 RC1 changed where this is set in the registry???? HKEY Local Machine/System/Current Control Set/Services/TCPIP/Parameters

mccoffee · Post by **mccoffee** » Sat Apr 03, 2004 4:44 pm

Take an a tcpip analyzer and cut and paste resaults??

Tailgunner9 · Post by **Tailgunner9** » Sat Apr 03, 2004 5:38 pm

Her it is just as I said, but is set at 63888 as always in registry where I have always set it until SP2 RC1 Thanks for any help Mr. Coffee

TCP options string = 020405ac01010402
MTU = 1492
MTU is optimized for PPoE DSL broadband. If not, consider raising MTU to 1500 for optimal throughput.
MSS = 1452
MSS is optimized for PPPoE DSL broadband. If not, consider raising MTU to 1500 for maximum throughput.

Default Receive Window (RWIN) = 64240
RWIN Scaling (RFC1323) = 0 bits
Unscaled Receive Window = 64240

For optimum performance, consider changing RWIN to a multiple of MSS.
Other values for RWIN that might work well with your current MTU/MSS:
511104 (MSS x 44 * scale factor of 8)
255552 (MSS x 44 * scale factor of 4)
127776 (MSS x 44 * scale factor of 2)
63888 (MSS x 44)

1. Your Tweakable Settings:
Receive Window (RWIN): 64240
Window Scaling: off
Path MTU Discovery: ON
RFC1323 Window Scaling: OFF
RFC1323 Time Stamping: OFF
Selective Acks: ON
MSS requested: 1452
TTL: unknown
TTL remaining: 53

2. Test 146000 byte download
Actual data bytes sent: 146000
Actual data packets: 101
Max packet sent (MTU): 1492
Max packet recd (MTU): 1492
Retransmitted data packets: 0
sacks you sent: 0
pushed data pkts: 5
data transmit time: 0.759 secs
our max idletime: 117.0 ms
transfer rate: 86001 bytes/sec
transfer rate: 688 kbits/sec
This is not a speed test!
transfer efficiency: 100%

mccoffee · Post by **mccoffee** » Sat Apr 03, 2004 6:15 pm

Try the following in cablenut see if you rwin changes after thease plus the othe vaules should help with interent performance

DefaultReceiveWindow =384000
DefaultSendWindow = 32768
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
IgnorePushBitOnReceives = 0
GlobalMaxTcpWindowSize = 63888
MaxFreeTcbs = 8000
MaxHashTableSize = 16384
MaxNormLookupMemory = 5000000
SackOpts = 1
SynAttackProtect = 1
Tcp1323Opts = 0
TcpLogLevel = 1
TcpMaxDupAcks = 3
TcpMaxHalfOpen = 100
TcpMaxHalfOpenRetried = 80
TcpRecvSegmentSize = 1452
TcpSendSegmentSize = 1452
TcpTimedWaitDelay = 30
TcpUseRFC1122UrgentPointer = 0
TcpWindowSize = 63888
MaxConnectionsPer1_0Server = 20
MaxConnectionsPerServer = 10
DefaultTTL = 64
DisableUserTOSSetting = 0
TcpMaxDataRetransmissions = 6
DefaultTOSValue = 92

Co/o manosteele52

. Under your LAN connection - properties - general tab, uninstall all the protocols there that you do not need.

2. Open IE and select tools - internet options - connections -
LAN settings, make sure NOTHING there is checked.

3. ALWAYS connect your modem via ethernet (NIC) and make sure you have the latest drivers for your NIC from the manufacturer. Set your NIC duplex mode to 10mb half duplex for Cable, for DSL it is ISP dependent unless you are using a router, if so then set it to 100mb full duplex for both Cable & DSL (the instructions are in my Help & Tips link). If you are using a router make sure you have the latest firmware.

4. Clear your temporary internet files.

5. Power cycle your modem, unplug it for atleast 15 seconds.

6. Download and update then do a scan with SpyBot 1.2 http://beam.to/spybotsd & Ad Aware 6.0 http://www.lavasoftusa.com/support/download to remove any spyware then install and update SpywareBlaster to stay spyware FREE. YOU MUST USE BOTH AD AWARE & SPYBOT TO ENSURE YOU ARE SPYWARE FREE SINCE ONE FINDS WHAT THE OTHER MISSES.

7. Make sure you do the faster web page tweak in Read1st link.

8. If you have Zone Alarm as a firewall uninstall it then visit Zonelabs.com for further instructions on removing it's left over junk.

9. Install Outpost Firewall [url]http://www.agnitum.com\[/url] or Sygate Firewall http://www.sygate.com/ , both have FREE and Pro versions and are heads above ZA.

10. Scan for viruses with your antivirus app, if you do not have one get one IMMEDIATELY, AVG 6.0 http://www.grisoft.com/us/us_dwnl_free.php is an excellent FREE AV app.

11. Make sure you have ALL of the latest Windows Updates.

Tailgunner9 · Post by **Tailgunner9** » Sat Apr 03, 2004 6:58 pm

Thanks Mr. Coffee. As you see below it increased my transfer rate. You have a nice weekend!!!!

Service: isdndslcablewirelesssatellite Speed (advertised) kbit/s: Operating System: win95win98win98SEwinMEwinNTwin2kwinXPMacLinuxFBSDSolaris Connection: normalwinpoetwinXPpppoerouterpppoeraspppoeenternetpppoA

1. Your Tweakable Settings:
Receive Window (RWIN): 384000
Window Scaling: 3
Path MTU Discovery: ON
RFC1323 Window Scaling: ON
RFC1323 Time Stamping: OFF
Selective Acks: ON
MSS requested: 1452
TTL:
(less any hops behind firewall)
64
TTL remaining: 53

2. Test 146000 byte download
Actual data bytes sent: 146000
Actual data packets: 101
Max packet sent (MTU): 1492
Max packet recd (MTU): 1492
Retransmitted data packets: 0
sacks you sent: 0
pushed data pkts: 1
data transmit time: 0.848 secs
our max idletime: 116.9 ms
transfer rate: 96982 bytes/sec
transfer rate: 775 kbits/sec
This is not a speed test!
transfer efficiency: 100%

3. ICMP (ping) check
Minimum ping: 62 ms
Maximum ping: 64 ms
Ping stability:
62 63 63 63 64 64 63 64 64 64

Notes and recommendations:
Input line speed for RWIN recommendation
Looking good

Notes and recommendations:
Good data stream (no/few rexmits)

Notes and recommendations:
Looking good

mccoffee · Post by **mccoffee** » Sat Apr 03, 2004 7:01 pm

Take a an analyzer the dslr tweak is showing the wrong i want to make sure on something

mnosteele52 · Post by **mnosteele52** » Sat Apr 03, 2004 7:25 pm

Tailgunner9 those are not the settings that mccoffee gave you.

Tailgunner9 · Post by **Tailgunner9** » Sat Apr 03, 2004 10:36 pm

Here are analyzer results you want Mr. Coffee

TCP options string = 020405ac0103030301010402
MTU = 1492
MTU is optimized for PPoE DSL broadband. If not, consider raising MTU to 1500 for optimal throughput.
MSS = 1452
MSS is optimized for PPPoE DSL broadband. If not, consider raising MTU to 1500 for maximum throughput.

Default Receive Window (RWIN) = 384000
RWIN Scaling (RFC1323) = 3 bits (scale factor of 6)
Unscaled Receive Window = 48000

For optimum performance, consider changing RWIN to a multiple of MSS.
Other values for RWIN that might work well with your current MTU/MSS:
511104 (MSS x 44 * scale factor of 8)
255552 (MSS x 44 * scale factor of 4)
127776 (MSS x 44 * scale factor of 2)
63888 (MSS x 44)

mccoffee · Post by **mccoffee** » Sat Apr 03, 2004 10:38 pm

As steele said double check your settings the analzyer should've shown 63888 where the 384000 is

Tailgunner9 · Post by **Tailgunner9** » Sat Apr 03, 2004 10:46 pm

Got it change to 63888. Here are results now. Thanks!!
TCP options string = 020405ac01010402
MTU = 1492
MTU is optimized for PPoE DSL broadband. If not, consider raising MTU to 1500 for optimal throughput.
MSS = 1452
MSS is optimized for PPPoE DSL broadband. If not, consider raising MTU to 1500 for maximum throughput.

Default Receive Window (RWIN) = 63888
RWIN Scaling (RFC1323) = 0 bits
Unscaled Receive Window = 63888

RWIN is a multiple of MSS
Other values for RWIN that might work well with your current MTU/MSS:
511104 (MSS x 44 * scale factor of 8)
255552 (MSS x 44 * scale factor of 4)
127776 (MSS x 44 * scale factor of 2)

1. Your Tweakable Settings:
Receive Window (RWIN): 63888
Window Scaling: off
Path MTU Discovery: ON
RFC1323 Window Scaling: OFF
RFC1323 Time Stamping: OFF
Selective Acks: ON
MSS requested: 1452
TTL:
(less any hops behind firewall)
64
TTL remaining: 53

2. Test 146000 byte download
Actual data bytes sent: 146000
Actual data packets: 101
Max packet sent (MTU): 1492
Max packet recd (MTU): 1492
Retransmitted data packets: 0
sacks you sent: 0
pushed data pkts: 5
data transmit time: 0.857 secs
our max idletime: 117.1 ms
transfer rate: 82694 bytes/sec
transfer rate: 661 kbits/sec
This is not a speed test!
transfer efficiency: 100%

3. ICMP (ping) check
Minimum ping: 63 ms
Maximum ping: 65 ms
Ping stability:
64 63 63 65 64 64 64 63 64 65

mccoffee · Post by **mccoffee** » Sat Apr 03, 2004 10:50 pm

What did you change if you changed the default recive window in cablenut ?? I think there might be a glinch in analyzer that's why i'm asking??

Tailgunner9 · Post by **Tailgunner9** » Sat Apr 03, 2004 10:54 pm

I changed the Default Receive Window from 384000 to 63888. Is this not what you said to change????

mccoffee · Post by **mccoffee** » Sat Apr 03, 2004 10:56 pm

Put it back to 38400 the analyzer is reading your info wrong that's what i thought.

Tailgunner9 · Post by **Tailgunner9** » Sat Apr 03, 2004 11:00 pm

Got it set on 38400, Here is analyzer results. Need other speed results??
TCP options string = 020405ac01010402
MTU = 1492
MTU is optimized for PPoE DSL broadband. If not, consider raising MTU to 1500 for optimal throughput.
MSS = 1452
MSS is optimized for PPPoE DSL broadband. If not, consider raising MTU to 1500 for maximum throughput.

Default Receive Window (RWIN) = 38400
RWIN Scaling (RFC1323) = 0 bits
Unscaled Receive Window = 38400

For optimum performance, consider changing RWIN to a multiple of MSS.
Other values for RWIN that might work well with your current MTU/MSS:
511104 (MSS x 44 * scale factor of 8)
255552 (MSS x 44 * scale factor of 4)
127776 (MSS x 44 * scale factor of 2)
63888 (MSS x 44)

mccoffee · Post by **mccoffee** » Sat Apr 03, 2004 11:07 pm

doh 384000 sorry last change busy night.

Post by **Philip** » Mon Apr 05, 2004 1:46 pm

There are 3 places in the Windows Registry where you can modify the RWIN value...

mccoffee · Post by **mccoffee** » Mon Apr 05, 2004 3:48 pm

I tought tcp window size was the default though or primary rwin unless i'm wrong??

Post by **Philip** » Mon Apr 05, 2004 5:06 pm

It has most probably been modified by something... In one of the other two locations.