Question:

We’re rather puzzled by what appears to be capped speeds on uploads,
despite no cap being set. Testing uploads, we’re seeing about 350
KB/s via the Ck library to our (local network) FTP server. A
FileZilla transfer of the same file to the same server can happily hit
up to 7MB/s.

I realize Ck supports bandwidth throttling, but those values are at
their default value of 0.

I’ve attached the relevant test code. There is one test file that
gets uploaded first, then we loop over an array of files. The first
file is tiny, then there’s a larger file (usually 20mb+), and on that
I see the ~350KB/s speeds.

Is this a familiar problem? Any known solutions, workarounds or
diagnostics you can suggest?

Answer:

Try setting the SendBufferSize property to a larger value. Perhaps
1MB instead of the default 64K.

Customer Response:

Thanks – that was the problem. Even with 512k buffers, I can happily max
out our local bandwidth.

Note: The default value for the SendBufferSize property will be change to 512K. This change will be documented in the release notes when the new version is available, as well as in the online documentation.