Обновив железо (MB ASUS P7P55D, сетевая Realtek PCe GBE Family Controller PCI\VEN_10EC&DEV_8168&SUBSYS_83A31043&REV_03) и операционку до Windows 7 x64, столкнулся с проблемой: при копировании больших (от 1ГБ) файлов по сети (вторая машина Windows 7 x32) происходят непредсказуемые зависания программы, которая производит этот процесс (FAR, Total Commander, Windows Explorer etc.). При это любое другое приложение имеет доступ к этим же ресурсам и пинги проходят нормально.

Приложение висело до такой степени, что ни taskman, ни procexp не могли его снять. При попытке закрыть хэндл открытого на сетевом ресурсе файла, эти менеджеры сами зависали навсегда. Не помогали никакие манипуляции с сетевым адаптером - devmgmr.msc тоже намертво висло.

Первой попыткой было пойти по стопам malyshev, но это помогло только на время - после получения виндой обновлений, в которые входили новые дрова на сетевуху, всё опять раскорячилось и назад уже никак не возвращалось, даже после реинсталляции "старых" дров.

В итоге выяснилось, что на втором компе (Intel DG45ID, Intel(R) 82567LF-2 Gigabit Network Connection,
PCI\VEN_10EC&DEV_8168&REV_03) желательно тоже провести те же настройки.

Но этого оказалось мало, всё это работало, пока процессор не загружался на 100%, тогда всё снова повторялось, в итоге использовал еще одно средство от Katarzyna (кратко тут). После этого всё встало на свои места.

Начал копировать кучу больших файлов с десктопа на ноут по сети и началось… Сетевая карточка просто отрубается, при этом в Event Log такое сообщение:

Проблема решена. Может быть кому-то пригодится.

Hi, my name is Katarzyna and I am the Program Manager within the Internet Protocols team. I have been asked a few times about the Receive Window Auto-Tuning feature on Vista and some associated issues people are having.

One of the many cool new features on Windows Vista, Receive Window Auto-Tuning enables the networking stack to receive data more efficiently than on XP. Auto-Tuning allows the operating system to continually monitor the routing conditions (bandwidth, network delay, application delay) and configure connections (scale the TCP Receiving Window) so as to maximize the network performance.In some high bandwidth, high latency links, we have seen SMB performance improvement up to 20 times!

In every TCP packet there is a "window" field, which informs the receiver how much data the sender can accept back. This window controls the flow by setting a threshold on data kept "in flight" and prevents overwhelming the receiver with data that it cannot accept.

The TCP window field is 16 bits wide, allowing for a maximum window size of 64KB, which used to meet requirements of many older networks. Nowadays, however, network interfaces can handle larger packets and keep more of them in flight at any given time. Thus, a larger TCP window has become necessary; especially on high-speed, high latency networks. To fill such a long, fat pipe and make use of the available bandwidth, the sending system can often require very large windows for good performance.

The solution to this demand is called "window scaling”, described back in 1992 in RFC 1323. It introduces an eight-bit scale factor, which serves as a multiplication factor for the window width. After the factor has been negotiated, window values used by that system on a given connection will be shifted to the left by that scale factor; a window scale of zero, thus, implies no scaling at all, while a scale factor of six implies that window sizes should be shifted six bits, thus multiplied by 2^6 = 64. Now a window greater than 64KB can be easily expressed (e.g., 128KB) by setting the scale factor (e.g., 6) and keeping the window field under the original 16 bits (here, 2048).

The window size included in all packets is modified by the scale factor, which is negotiated once at the very beginning of a TCP connection. The connection requestor suggests window scaling factor in its original SYN packet and if the SYN+ACK packet sent in response contains the option, then this particular value will be used on this connection. The scale factor cannot be changed after the initial setup handshake; remaining data transfers on this connection will implicitly use the negotiated value.

Older routers and firewalls however do not handle window scaling correctly leaving the option in the original SYN packet but setting the connection’s scale factor to zero. Seeing the option on, the receiver responds with its own window scale factor. Believing that its scale factor has been accepted, the initiator scales the window appropriately while the receiver thinks that a scale factor of zero is applied and thus a small window of data should follow. As a result, the communication is slow at best. Sometimes, small window packets are dropped by the routers, essentially breaking the connection.

The resulting slow data transfers or loss of connectivity, users may experience as slow or hung networking applications. Remote Desktop Connection and network file copy are two scenarios particularly hurt by misbehaving routers.

If your connection from a Vista machine appears slow or hung, here are some steps to isolate the cause:

• First, make sure that your firewall and router can support window scaling. Some devices from Linksys, Cisco, NetApp, SonicWall, Netgear, Checkpoint, D-Link were reported as having problems with window scaling. (Some of the incompatible devices are given here. You can check with the manufacturer or run the connectivity diagnostic suite (especially, TCP High Performance Test) provided by Microsoft to determine your gateway device’s compliance.
• Second, check with the manufacturer if a firmware update has been issued for your device that can fix the problem. Replace the problematic device or update the firmware as suggested by the manufacturer. If the router cannot be replaced or if it the device is remote (e.g., a firewall of your ISP or corporation)
• Third, If the problem still persists, you can restrict autotuning by running “netsh interface tcp set global autotuninglevel=restricted” from the command prompt. We have found that restricted mode will often allow some of the benefits of autotuning with a number of problematic devices.
• Lastly, if all else fails, in order to disable this feature, run "netsh interface tcp set global autotuninglevel=disabled".
• (In order to reenable autotuning, run “netsh interface tcp set global autotuninglevel=normal”.)

Please refer to the following KB articles for more information:

• KB 932170: When you copy large files to or from earlier operating systems, the copy operation may be slower than expected on some Windows Vista-based computers
• KB 929868: A Web site sends data very slowly or drops the data completely when you use Windows Vista Enterprise
• KB 935400: It takes a very long time to download an e-mail message from a POP3 server in Outlook 2007

-- Katarzyna

If you’ve been having problems copying large files over mapped drives, network disconnects, or having to reboot your router a lot more often than normal, then you can try out this fix to solve the problem.

The problem stems from the new auto-tuning network, which changes the receive window on the fly. Thankfully we can easily turn it off from an administrative mode command prompt.

Open Administrative Mode Command Prompt

Either type cmd into the start menu and use Ctrl+Shift+Enter or right-click the Command Prompt shortcut and choose Run as Administrator.

Turn Off Auto-Tuning

netsh int tcp set global autotuninglevel=disabled

You’ll have to reboot your system, but once you do, the problems should be resolved. If they are not you can always turn auto-tuning back on.

Turn On Auto-Tuning

netsh int tcp set global autotuninglevel=normal

For more information on this topic, you can read this article from MSDN blogs.