Send / receive buffer of SmartFTP

Hi all,

Do you know what is the size of Send/Receive buffer SmartFTP uses?

Can we set it manually somewhere, or will SmartFTP use the default settings from Windows?

Many thanks in advance.

A lot of builds ago there was a setting for change that, but ATM you can't.

Then it uses the send/receive buffer settings of Windows, doesn't it?

Hello ..

SmartFTP uses a 1KB send buffer (The file IO buffer is bigger to avoid too many ReadFile calls). But it doesnt change the TCP window buffer sizes.

-Mat

Hi Mat,

We are using SmartFTP to upload big-size files from a host in Austin to a FTP server in Beijing. The available bandwidth is 512kbps. However, because of large round trip time(500ms latency), the transfer speed limits at 150kbps.

According to TCP, the receiver (here is the FTP server) advertises its maximum window size to give the sender (here is SmartFTP) an idea of how much buffer space the receiver has available. This puts a hard limit on size of the window, even if more bandwidth is available in the network.

Trying to improve the transfer speed, we increase the window size (or receive buffer) of FTP server. So I just wonder, whether SmartFTP will adjust its send buffer based on the windows size of FTP server?

Many thanks.

SmartFTP does not change the TCP recv/send window buffers. It uses the default values provided by the OS. As far as I know they are getting adjusted by the OS adaptively.

You can manually adjust the TCP window size in the registry.

Do you have faster transfer speed with any other FTP client out there?