Auto Tuning - TCP/IP receive level

ByLine
How to Enable or Disable the Receive Window Auto Tuning Level in Vista
Synopsis
This will show you how to see your current TCP/IP Auto Tunning settings and how to test it to see if you have a problem with it. You will see a list of possible problems associated with this.
How to Enable or Disable the Receive Window Auto Tuning Level in Vista

information   Information
The TCP receive window size (RWIN) is the amount of data that a TCP receiver (your computer) allows a TCP sender (other internet or local network computer) to send before having to wait for an acknowledgement. After the connection is established, the receive window size is advertised in each TCP segment. Advertising that maximum amount of data that the sender can send is a receiver-side flow control mechanism that prevents the sender from sending data that the receiver cannot handle. A sending host can only send at a maximum the amount of data advertised by the receiver before waiting for an acknowledgment and a receive window size update. Auto Tuning adjusts the receive windows size continually based upon the changing network conditions. This usually happens if you have a network device (EX: Router, modem, etc.) that doesn’t support RFC 1323 “TCP Extensions for High Performance”.
Note   Note
The TCP window size field controls the flow of data and is limited to between 2 and 65,535 bytes, and cannot be expanded anymore. Thus, a scaling factor is used to get a larger TCP receive window size to achieve more efficient use of high bandwidth networks. The TCP window scale option is used to increase the maximum window size from 65,535 bytes to 1 Gigabyte. Scaling up to larger TCP congestion window sizes is a part of what is necessary for TCP Tuning.

When dealing with slow network performance in Vista, the problem may be due to the above mentioned TCP Window Scaling option, where many older routers and and packet firewalls do not properly implement TCP Window Scaling (doesn’t support RFC 1323), and rewrite the window scaling factor during a transmission, and causing sending and receiving sides to assume different TCP window sizes. The situation causes malfunction Internet connection, non-stable traffic that is very slow, or network connection that is only available intermittently.

Beside, Windows Vista enhances further TCP window scaling with auto tuning feature, where TCP stack in Vista system will auto tune and adjust the RWIN size to increase the percentage of full-sized TCP segments that are used during bulk data transmission based on the network scenario it encountered. And thus it’s no longer possible to specify a custom size for the TCP/IP Receive Window (RWIN) size with the inclusion of new auto tuning feature, unless the application it self uses SO_RCVBUF. However, Vista TCP auto tuning feature may get things wrong sometimes. Instead of optimal true receive window size, incompatible and out of range RWIN size may be used.

By default, Vista in normal auto tuning level will use RWIN size of 256 bytes with a scale factor of 8. This value is not suitable for all routers and servers which does not support TCP scale factor, and continue to communicate with 65536 bytes.

UPDATE: An Update on Windows TCP AutoTuningLevel - Windows 10 Forums

Tip   Tip
Possible TCP/IP Auto Tuning Related Problems:
  • Indefinite delay (hang) when opening the Certificate Services snap-in.
  • Slow (sometimes no) group policy application.
  • Trying to select a domain user in order to add that principal to a local security group (the object picker) would hang indefinitely.
  • Instant Messaging is not working well. Sometimes not at all by not being able to sign in.
  • Access to local file servers (EX: networked drives, etc.) are extremely slow and sometimes did not succeed at all (appears to hang).
  • Internet connection problems.
  • Extremely slow file transfers.
  • Other strange unexplained network connecting issues.
  • Wireless network connection problems
  • Website browsing and downloads are extremely slow.





FIRST
How To See Current Auto Tuning Settings

2. Click on Continue in the UAC prompt.​
3. In the command prompt, type in bold belowand press Enter. (See screenshot below)​
netsh interface tcp show global
Current setting.jpg

4. Close the command prompt when done.​
5. Run through the steps below to see if you have a TCP/IP Auto Tuning issue​





STEP ONE
How to Restrict Auto Tuning

2. Click on Continue in the UAC prompt.​
3. To Restrict Auto Tuning
NOTE: Allows for the receive window to grow beyond the default value of 65,535 bytes, but limits such growth in some scenarios.​
A) In command prompt, type in bold below and press Enter. (See screenshot below)​
netsh interface tcp set global autotuninglevel=restricted

B) You will get a OK response if successful. If not, repeat step 3A.​
Restricted.jpg

C) Go to step 5.​

4. To Highly Restrict Auto Tuning
NOTE: Allows for the receive window to grow beyond the default value of 65,535 bytes, but doing so very conservatively. In this mode, Vista will by default use a RWIN of 16,384 bytes with a scale factor of 2.​
A) In the command prompt, type in bold below and press Enter. (See screenshot below)​
netsh interface tcp set global autotuninglevel=high

B) You will get a OK response if successful. If not, repeat step 4A.​
Highly restricted.jpg


5. Close the command prompt window and restart the computer to apply the changes.​
6. If it fixed your problem stop here. If not, continue to Step Two below.​






STEP TWO
How to Disable Auto Tuning

NOTE: Disables the autotunning feature in Vista completely, and sets and locks the RWIN receive window to the default value as 65536 bytes.
2. Click on Continue in the UAC prompt.​
3. In the command prompt, type in bold belowand press Enter. (See screenshot below)​
netsh interface tcp set global autotuninglevel=disabled

Note   Note
You can also type in bold below and press enter after each command:
Note   Note

  • netsh
  • interface
  • tcp
  • set heuristics disabled
  • set global autotuninglevel=disabled
  • exit
4. You will get a OK response. If not, repeat step 3.​
Disable.jpg

5. Close the command prompt and restart the computer to apply the changes.​
6. If it fixed your problem stop here. If not, you may not have a issue with Auto Tuning and will need to turn it back on. Continue to Step 3 below.​






STEP THREE
How to Enable Auto Tuning Back to Normal Default

NOTE: This turns Auto Tuning back to the default on (Normal) setting in Vista. Allows for the receive window to grow to accommodate almost all scenarios. See NOTE at the top of the tutorial for more on this.
2. Click on Continue in the UAC prompt.​
3. In the command prompt, type in bold below and press Enter. (See screenshot below)​
netsh interface tcp set global autotuninglevel=normal

Note   Note
You can also type in bold below and press enter after each command:
Note   Note

  • netsh
  • interface
  • tcp
  • set heuristics enabled
  • set global autotuninglevel=normal
  • exit
4. You will get a OK response if successful. If not, repeat step 3.​
Enable.jpg

5. Close the command prompt and restart the computer to apply the changes.​
That's it,
Shawn


 

Attachments

  • thumb_14710223270Network.png
    thumb_14710223270Network.png
    10.4 KB · Views: 113
Last edited by a moderator:

Brink

Staff member
mvp
That's great news. The Step Two sections restricts it the highest since it disables Auto Tuning. :)
 

My Computers

System One System Two

  • Operating System
    Windows 10 Pro 64-bit
    Manufacturer/Model
    Custom
    CPU
    Intel i7-8700K 5 GHz
    Motherboard
    ASUS ROG Maximus XI Formula Z390
    Memory
    16 GB (8GBx2) G.SKILL TridentZ DDR4 3200 MHz
    Graphics Card(s)
    ASUS ROG-STRIX-GTX1080TI-O11G-GAMING
    Sound Card
    Integrated Digital Audio (S/PDIF)
    Monitor(s) Displays
    2 x Samsung Odyssey G7 27"
    Screen Resolution
    2560x1440
    Hard Drives
    1TB Samsung 970 EVO Plus M.2,
    250GB Samsung 960 EVO M.2,
    6TB WD Black WD6001FZWX
    8TB WD MyCloudEX2Ultra NAS
    PSU
    Seasonic Prime Titanium 850W
    Case
    Thermaltake Core P3
    Cooling
    Corsair Hydro H115i
    Mouse
    Logitech MX Master 3
    Keyboard
    Logitech wireless K800
    Internet Speed
    1 Gb/s Download and 35 Mb/s Upload
    Other Info
    Logitech Z625 speaker system,
    Logitech BRIO 4K Pro webcam,
    HP Color LaserJet Pro MFP M477fdn,
    Linksys EA9500 router,
    Arris SB8200 cable modem,
    APC SMART-UPS RT 1000 XL - SURT1000XLI,
    Lumia 1520 phone
  • Operating System
    Windows 10 Pro
    Manufacturer/Model
    HP Envy Y0F94AV
    CPU
    i7-7500U @ 2.70 GHz
    Memory
    16 GB DDR4-2133
    Graphics card(s)
    NVIDIA GeForce 940MX
    Sound Card
    Conexant ISST Audio
    Monitor(s) Displays
    17.3" UHD IPS touch
    Screen Resolution
    3480 x 2160
    Hard Drives
    512 GB M.2 SSD
K Im running alot faster now, I will try downloading larger files to be sure... Thank you for your help...
Call me a friend any time.
 

My Computer

System One

  • Manufacturer/Model
    Acer Aspire 5315
    Memory
    2 gb
    Hard Drives
    C drive
    D Drive
    Case
    Standard Acer Aspire Case
    Cooling
    Cooling Pad and USB Desklamp/fan combo
    Mouse
    Logitech
    Keyboard
    Logitech
    Internet Speed
    DSL 20mb/s
    Other Info
    I run a 60watt speakers from my headphone jack, and I got 10port USB HUB USB Wireless adapter foer the internet

Brink

Staff member
mvp
You're most welcome. Please let us know your results. :)
 

My Computers

System One System Two

  • Operating System
    Windows 10 Pro 64-bit
    Manufacturer/Model
    Custom
    CPU
    Intel i7-8700K 5 GHz
    Motherboard
    ASUS ROG Maximus XI Formula Z390
    Memory
    16 GB (8GBx2) G.SKILL TridentZ DDR4 3200 MHz
    Graphics Card(s)
    ASUS ROG-STRIX-GTX1080TI-O11G-GAMING
    Sound Card
    Integrated Digital Audio (S/PDIF)
    Monitor(s) Displays
    2 x Samsung Odyssey G7 27"
    Screen Resolution
    2560x1440
    Hard Drives
    1TB Samsung 970 EVO Plus M.2,
    250GB Samsung 960 EVO M.2,
    6TB WD Black WD6001FZWX
    8TB WD MyCloudEX2Ultra NAS
    PSU
    Seasonic Prime Titanium 850W
    Case
    Thermaltake Core P3
    Cooling
    Corsair Hydro H115i
    Mouse
    Logitech MX Master 3
    Keyboard
    Logitech wireless K800
    Internet Speed
    1 Gb/s Download and 35 Mb/s Upload
    Other Info
    Logitech Z625 speaker system,
    Logitech BRIO 4K Pro webcam,
    HP Color LaserJet Pro MFP M477fdn,
    Linksys EA9500 router,
    Arris SB8200 cable modem,
    APC SMART-UPS RT 1000 XL - SURT1000XLI,
    Lumia 1520 phone
  • Operating System
    Windows 10 Pro
    Manufacturer/Model
    HP Envy Y0F94AV
    CPU
    i7-7500U @ 2.70 GHz
    Memory
    16 GB DDR4-2133
    Graphics card(s)
    NVIDIA GeForce 940MX
    Sound Card
    Conexant ISST Audio
    Monitor(s) Displays
    17.3" UHD IPS touch
    Screen Resolution
    3480 x 2160
    Hard Drives
    512 GB M.2 SSD
how do I test the results??? Do I go to a speed test site like the one posted in the forum or what????

OK I doubled my speed to around 20 mb/s, I hope I can get faster than that, but I think my internet only goes up to 20mb/s
 

My Computer

System One

  • Manufacturer/Model
    Acer Aspire 5315
    Memory
    2 gb
    Hard Drives
    C drive
    D Drive
    Case
    Standard Acer Aspire Case
    Cooling
    Cooling Pad and USB Desklamp/fan combo
    Mouse
    Logitech
    Keyboard
    Logitech
    Internet Speed
    DSL 20mb/s
    Other Info
    I run a 60watt speakers from my headphone jack, and I got 10port USB HUB USB Wireless adapter foer the internet

Brink

Staff member
mvp
That's great news. Yeah, it depends on what plan you have with your ISP for what your download and upload bandwidth limits are.
 

My Computers

System One System Two

  • Operating System
    Windows 10 Pro 64-bit
    Manufacturer/Model
    Custom
    CPU
    Intel i7-8700K 5 GHz
    Motherboard
    ASUS ROG Maximus XI Formula Z390
    Memory
    16 GB (8GBx2) G.SKILL TridentZ DDR4 3200 MHz
    Graphics Card(s)
    ASUS ROG-STRIX-GTX1080TI-O11G-GAMING
    Sound Card
    Integrated Digital Audio (S/PDIF)
    Monitor(s) Displays
    2 x Samsung Odyssey G7 27"
    Screen Resolution
    2560x1440
    Hard Drives
    1TB Samsung 970 EVO Plus M.2,
    250GB Samsung 960 EVO M.2,
    6TB WD Black WD6001FZWX
    8TB WD MyCloudEX2Ultra NAS
    PSU
    Seasonic Prime Titanium 850W
    Case
    Thermaltake Core P3
    Cooling
    Corsair Hydro H115i
    Mouse
    Logitech MX Master 3
    Keyboard
    Logitech wireless K800
    Internet Speed
    1 Gb/s Download and 35 Mb/s Upload
    Other Info
    Logitech Z625 speaker system,
    Logitech BRIO 4K Pro webcam,
    HP Color LaserJet Pro MFP M477fdn,
    Linksys EA9500 router,
    Arris SB8200 cable modem,
    APC SMART-UPS RT 1000 XL - SURT1000XLI,
    Lumia 1520 phone
  • Operating System
    Windows 10 Pro
    Manufacturer/Model
    HP Envy Y0F94AV
    CPU
    i7-7500U @ 2.70 GHz
    Memory
    16 GB DDR4-2133
    Graphics card(s)
    NVIDIA GeForce 940MX
    Sound Card
    Conexant ISST Audio
    Monitor(s) Displays
    17.3" UHD IPS touch
    Screen Resolution
    3480 x 2160
    Hard Drives
    512 GB M.2 SSD
Yeah my internet is running better now thank you very much my friend.. Later Im going to upload pics of MY RIG....Simple Laptop with 60watt speakers ...10port USB HUB...MOUSE/Keyboard and webcam with a printer/Scanner/copier

I printed out the list of services from Black Viper, so today im going to tweak my services...hoping to start quicker.

Now Im not getting net at all, I just went into msconfig and saw that my os was not ticked and so was some of my other microsoft features... I just rebooted my computer like 2 min ago, just waiting for it to load up.....
 

My Computer

System One

  • Manufacturer/Model
    Acer Aspire 5315
    Memory
    2 gb
    Hard Drives
    C drive
    D Drive
    Case
    Standard Acer Aspire Case
    Cooling
    Cooling Pad and USB Desklamp/fan combo
    Mouse
    Logitech
    Keyboard
    Logitech
    Internet Speed
    DSL 20mb/s
    Other Info
    I run a 60watt speakers from my headphone jack, and I got 10port USB HUB USB Wireless adapter foer the internet
Top