Why do I see different TCP behaviour between IIS and FTP server applications on Windows 2003?
Posted
by
rupello
on Server Fault
See other posts from Server Fault
or by rupello
Published on 2011-06-27T19:41:59Z
Indexed on
2011/06/30
8:24 UTC
Read the original article
Hit count: 156
I am comparing Wireshark traces of a 10MB file download file from:
- the FileZilla FTP server and
- IIS (using HTTP) on the same Windows 2003 server.
The FTP download performs faster and the trace shows the server behaving as expected, sending more data to the client with every ACK received:
The HTTP server trace shows a more bursty pattern. The timing of the send bursts are sometimes unrelated to any ACKs received from the client (circled in red):
Anyone have a suggestion as to why IIS traffic is having like this?
Update: We have tried modifying the http.sys registry settings (setting MaxBytesPerSend to 256k and MaxBufferedSendBytes to 64k as recommended). Changing MaxBytesPerSend does seem to improve performance by increasing the amount of in-flight data , but we still see the same bursty pattern.
© Server Fault or respective owner
