Upload stays at 4 Mbps with 15Mbps service

[sootsnoot]

Running XP Home, SP3

I previously had Verizon Fios with 10-down/5-up, and speed tests confirmed that's about what I was getting - well I seldom actually got quite 5 up, generally less than 4.

I just upgraded to Fios with 25-down/15-up. After the upgrade, tests still only got 10-down/4-up. Called Verizon support, and they suggested running the SG optimizer. I did that, and it got me to 26-down/4-up. Another call to support, checked a bunch of stuff, and they decided to send a tech out for on-site diagnosis. We unplugged the Cat-5e ethernet cable from my XP SP3 system, and plugged it into to his XP SP3 laptop, and he got 26-down/19-up. Moved the cable to my Vista SP2 laptop and also to another of my XP SP3 systems where I ran the SG optimizer; both of these measured 26-down/4-up
(Vista got a little more than 5 up).

We then ran the SG optimizer on his XP SP3 laptop and also on my XP SP3 laptop again. On both systems we slid the connection speed all the way to 20000, selected the "Optimal settings" button, applied changes, and compared the new settings shown for the two laptops - all settings shown on the page following the press of "Apply changes" were identical on the two laptops. Then we rebooted both laptops and re-ran speed tests (using both myspeed.visualware.com and speedtest.net). The tech's Panasonic laptop got 26-down/19-up, while my HP laptop still got 26-down/4-up. I have Eset Smart Security installed, but I disabled the firewall for the speed tests (it made no appreciable difference). My other XP SP3 system showed similar performance - the SG optimizer boosted the download speed from around 10 to around 26, but the upload speed remained unchanged at around 4. The Vista 32-bit Home Premium SP2 system gave 26/5 before any tweaking. I applied the "SG Vista TCP/IP Patch" version 1.3, and that made no significant change - maybe the upload went from 4.5 to 5.5.

This totally stumped both the Verizon tech and me. All three of my computers (two running XP and one running Vista) measure 26-down/4-up. But his XP SP3 laptop with the same SG Optimizer settings as my two XP SP3 systems measures 26-down/19-up, using the exact same physical ethernet connection. Does anybody have any ideas? My only thought was the Eset Firewall, but I disabled it. Here's the Analyzer output from my laptop (didn't run the analyzer as such on the tech's laptop, just compared the new settings in the optimizer screen, and yes, we scrolled them down to the end comparing line-by-line).

? SpeedGuide.net TCP Analyzer Results ?
Tested on: 11.23.2009 13:23
IP address: 173.76.xxx.xxx
Client OS: Windows XP

TCP options string: 020405b40103030401010402
MSS: 1460
MTU: 1500
TCP Window: 1027840 (multiple of MSS)
RWIN Scaling: 4 bits (2^4=16)
Unscaled RWIN : 64240
Recommended RWINs: 64240, 128480, 256960, 513920, 1027840
BDP limit (200ms): 41114kbps (5139KBytes/s)
BDP limit (500ms): 16445kbps (2056KBytes/s)
MTU Discovery: ON
TTL: 43
Timestamps: OFF
SACKs: ON
IP ToS: 00000000 (0)

[trogers]

Download Cablenut and set only this field:

DefaultSendWindow - 256000

Reboot and test speed.

[sootsnoot]

Wow, you're definitely onto something - this boosted upload from 4 to 19.8!! Only problem is that it dropped download from 26.0 to 18.4 (the 26.0 down has been 100% reproducible on all the computers, and still is on the ones I didn't change). Any ideas on that one? Alternatively, I guess I could call Verizon again, and see if I could get the same tech to install cablenut, have it get his registry values, and send them to me, since his laptop got 26.0-down and something over 19-up every time.

Thanks a million!

-Rich

[sootsnoot]

I played around a little with cablenut, and saw that if you ask it to get registry values, it only seems to get values you adjusted, so perhaps getting the Verizon tech to report his values might not reveal anything. But I also searched for DefaultSendWindow, and came across http://forums.speedguide.net/showthread.php?t=185104 :

DefaultReceiveWindow - The number of receive bytes that AFD buffers on a connection before imposing flow control. For some applications, a larger value here gives slightly better performance at the expense of increased resource utilization.

Value Type: REG_DWORD

Default: 4096/8192/8192

To find your optimum value: caps / 8 x 1024 i.e. caps of 5000 (5000 / 8 x 1024 = 640000. This value is based on bytes of memory, this is why you multiply by 1024, 1024 = 1mb or memory.

DefaultSendWindow - This is similar to DefaultReceiveWindow, but for the send side of connections.

Value Type: REG_DWORD

Default: 4096/8192/8192

This is calculated the same as DefaultReceiveWindow.

So I went back to cablenut and set:
DefaultReceiveWindow=(25*1024)/8 * 1024 = 3276800
DefaultSendWindow=(15*1024)/8 * 1024 = 1966080

After reboot, I'm getting 26.0 down and 19.8 up!

Thanks very much for your help!

-Rich

[sootsnoot]

Two more questions:

1. The calculation for Default(Send|Receive)Window in the referenced thread uses the term "caps" apparently to mean line capacity in kbps. Since I'm supposed to be getting 25 Mbps down, I used (25 * 1024) for caps. But do throughput numbers normally use binary k (1024) or decimal k (1000)? My systems programming experience made me assume that it's binary k, but some other things I've seen make me think that decimal k is what's meant in this context... I guess I'll try plain 1000 and see what happens, since making the numbers bigger than necessary apparently wastes memory.

2. On my Vista Home Premium SP2 system I got the 26.0 down without any tweaking, but it only gets 5 or 6 up. Neither SG Optimizer nor Cablenut seem to support Vista. I did run the SG Vista TCP/IP Patch version 1.3, but as I said in the first post that didn't make any noticeable difference. Does it make sense to try manually adding a REG_DWORD DefaultSendWindow parameter to HKLM\SYSTEM\CurrentControlSet\Services\AFD\Parameters to the Vista registry - or is Vista TCP sufficiently different from XP that it would be a bad idea?

Thanks,

-Rich

[sootsnoot]

I changed the calculation above to use decimal k:

DefaultReceiveWindow=(25*1000)/8 * 1024 = 3200000
DefaultSendWindow=(15*1000)/8 * 1024 = 1920000

I put these two values on two of the XP SP3 systems using cablenut, rebooted, and then both consistently measured 26.0-down/20.5-up. I then undid the changes made by the SG optimizer, leaving only these two changes in place on both systems, and still got exactly the same speed. The "detailed analysis" from myspeed.visualware.com showed a fairly steady graph for transfer speed, and fairly regular pattern in the pause graph, suggesting the speed was being throttled. The quality of service for download was 99%, and for upload varied between 88% and 99%. Probably can't do much better than this!

So at least in my situation, it seems that the changes made by the SG optimizer were not significant. Here's what the analyzer now says:

« SpeedGuide.net TCP Analyzer Results »
Tested on: 11.25.2009 02:20
IP address: 173.76.xxx.xxx
Client OS: Windows XP

TCP options string: 020405b40103030601010402
MSS: 1460
MTU: 1500
TCP Window: 3200000 (NOT multiple of MSS)
RWIN Scaling: 6 bits (2^6=64)
Unscaled RWIN : 50000
Recommended RWINs: 64240, 128480, 256960, 513920, 1027840
BDP limit (200ms): 128000kbps (16000KBytes/s)
BDP limit (500ms): 51200kbps (6400KBytes/s)
MTU Discovery: ON
TTL: 107
Timestamps: OFF
SACKs: ON
IP ToS: 00000000 (0)

With such seemingly ideal performance, is there anything to be gained by further tweaking, e.g. making RWIN a multiple of MSS?

Thanks,

-Rich

[sootsnoot]

Seem to be on a roll, so I tried regedit on the Vista SP2 system, which had been getting 26.0-down/5.5-up.

I added just the one value:
HKLM\SYSTEM\CurrentControlSet\Services\AFD\Parameters\DefaultSendWindow REG_DWORD 0x001d4c00 (1920000)

After reboot, I'm getting 26.0-down/20.5 up!

[100 010 00]

of course u did it right. default send window works fine on vista and optimizes the upload speed to full leave it as it is

[akbarri]

Originally Posted by sootsnoot

I changed the calculation above to use decimal k:

DefaultReceiveWindow=(25*1000)/8 * 1024 = 3200000
DefaultSendWindow=(15*1000)/8 * 1024 = 1920000

I put these two values on two of the XP SP3 systems using cablenut, rebooted, and then both consistently measured 26.0-down/20.5-up. I then undid the changes made by the SG optimizer, leaving only these two changes in place on both systems, and still got exactly the same speed. The "detailed analysis" from myspeed.visualware.com showed a fairly steady graph for transfer speed, and fairly regular pattern in the pause graph, suggesting the speed was being throttled. The quality of service for download was 99%, and for upload varied between 88% and 99%. Probably can't do much better than this!

So at least in my situation, it seems that the changes made by the SG optimizer were not significant. Here's what the analyzer now says:

« SpeedGuide.net TCP Analyzer Results »
Tested on: 11.25.2009 02:20
IP address: 173.76.xxx.xxx
Client OS: Windows XP

TCP options string: 020405b40103030601010402
MSS: 1460
MTU: 1500
TCP Window: 3200000 (NOT multiple of MSS)
RWIN Scaling: 6 bits (2^6=64)
Unscaled RWIN : 50000
Recommended RWINs: 64240, 128480, 256960, 513920, 1027840
BDP limit (200ms): 128000kbps (16000KBytes/s)
BDP limit (500ms): 51200kbps (6400KBytes/s)
MTU Discovery: ON
TTL: 107
Timestamps: OFF
SACKs: ON
IP ToS: 00000000 (0)

With such seemingly ideal performance, is there anything to be gained by further tweaking, e.g. making RWIN a multiple of MSS?

Thanks,

-Rich

good start > http://forums.speedguide.net/showthread.php?t=185104

if u set "DefaultReceiveWindow", it will override "TCP Window" value on TCP Analyzer so "RWIN cannot multiple of MSS" cause calculated differently

see what u get with this setting

CABLENUT :
DefaultReceiveWindow = BLANK
DefaultSendWindow = 1920000

TCPO :
General Settings tab:
Custom settings - check
Modify All Network Adapters - check
network adapter selection - your NIC
MTU - 1500
TTL - 64
TCP Receive Window - 1027840
MTU Discovery - Yes
Black Hole Detect - No
Selective Acks - Yes
Max Duplicate ACKs - 2
TCP 1323 Options:
Windows Scaling - check
Timestamps - uncheck

Advanced Settings tab:
Max Connections per Server - 10
Max Connections per 1.0 Server - 10
LocalPriority - 5
Host Priority - 6
DNSPriority - 7
NetbtPriority - 8
Lan Browsing speedup - optimized
QoS: NonBestEffortLimit - 0
ToS: DisableUserTOSSetting - blank
ToS: DefaultTOSValue - blank
MaxNegativeCacheTtl - 0
NetFailureCacheTime - 0
NegativeSOACache Time - 0
LAN Request Buffer Size - 32768

[trogers]

Putting a value in the field DefaultReceiveWindow of Cablenut will override TCP Window when using XP, but not earlier OS like Windows 2000.

So your TCP Window should follow TCP Optmizer's recommended settings, and when using Cablenut, leave a blank for DefaultReceiveWindow.

The AFD sending buffer in XP (and maybe in Vista/WIN7) is default at 8192 bytes.

Thus in your case of limited upload speed, we try increasing this buffer size by putting a value to DefaultSendWindow.

[sootsnoot]

Thanks for the really helpful replies! I followed the advice from akbarri, and the analyzer now shows:

« SpeedGuide.net TCP Analyzer Results »
Tested on: 11.25.2009 10:31
IP address: 173.76.xxx.xxx
Client OS: Windows XP

TCP options string: 020405b40103030401010402
MSS: 1460
MTU: 1500
TCP Window: 1027840 (multiple of MSS)
RWIN Scaling: 4 bits (2^4=16)
Unscaled RWIN : 64240
Recommended RWINs: 64240, 128480, 256960, 513920, 1027840
BDP limit (200ms): 41114kbps (5139KBytes/s)
BDP limit (500ms): 16445kbps (2056KBytes/s)
MTU Discovery: ON
TTL: 43
Timestamps: OFF
SACKs: ON
IP ToS: 00000000 (0)

That gets TCP window a multiple of MSS. But in running speed tests several more times, I'm getting upload speeds of 20.2 and 20.3, never reaching the 20.5 I was getting consistently before making this change. OTOH, the other XP machine where I didn't make akbarri's change is also showing 20.3, so I guess that's just a variation in the network. Might as well get TCP window a multiple of MSS on all the machines, and then relax.

Thanks again to all!

-Rich