Knowledge Base

Article 2558

How To change Transfer Buffer Sizes

Explanation

"File Buffer Size"
Size of the buffer in bytes to be used to read data from a local file. The value must be equal or larger than the value of the "Send Buffer Size".
Default: 32 KB

"Send Buffer Size"
Size of the buffer in bytes to be used to send data to a connected socket.
Important: The value must be smaller or equal than the "File Buffer Size" value.
Default: 4 KB

"Receive Buffer Size"
Size of the buffer in bytes to be used to receive data from a connected socket.
Default: 8 KB

Optimizations for High Speed Connections (100mbit/s+)
Set "File Buffer Size" to 64 KB
Set "Send Buffer Size" to 32 KB
Set "Receive Buffer Size" to 32 KB
Set the "GlobalMaxTcpWindowSize" in the windows registry to 256960. See "Windows 2000/XP Registry Tweaks" for details. 

How To

1. Select Favorites > Edit Favorites from the SmartFTP menu. The Favorites window appears.
2. From the SmartFTP Favorites window select the Favorite to be used. Right click on the Favorite and select Properties. The Properties dialog appears.
3. Select Transfer > Performance. From the Performance tab under Buffer Sizes you can change the transfer buffer sizes.

Important
Setting the values higher for low speed connections may slow down the transfers and the speed calculation becomes inaccurate.

References
- MSDN - getsockopt [Winsock]
- Design issues - Sending small data segments over TCP with Winsock
- Windows 2000/XP Registry Tweaks

Keywords
transfer, buffer, size, slow, upload

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