G
Guest
When I was using the MGET command to copy large amount of files from a folder
(directory) on a server using FTP, the file transfer paused frequently and
then ended with the message 'connection closed by remote host'. Sometimes it
worked and sometimes it failed. Apparently, SACK (selective acknowledgment)
is enabled by default, and it is not working correctly in some case. To fix
this problem, you can add a new setting in TCP/IP registry: SackOpts (DWORD,
value '0') to disable the SACK.
Microsoft will need to look at the code that implements the SACK feature. It
seemed to time out too quick and there was no way to tune it either.
The problem surfaced in other form as well. Some user applications having
lots of bulk data transfer frozen for no reason. It occurred intermitently
and it was hard to nail down. Eventually, the cause of this freeze problem
was identified --- the default SACK feature (enabled) in the TCP/IP stack.
(directory) on a server using FTP, the file transfer paused frequently and
then ended with the message 'connection closed by remote host'. Sometimes it
worked and sometimes it failed. Apparently, SACK (selective acknowledgment)
is enabled by default, and it is not working correctly in some case. To fix
this problem, you can add a new setting in TCP/IP registry: SackOpts (DWORD,
value '0') to disable the SACK.
Microsoft will need to look at the code that implements the SACK feature. It
seemed to time out too quick and there was no way to tune it either.
The problem surfaced in other form as well. Some user applications having
lots of bulk data transfer frozen for no reason. It occurred intermitently
and it was hard to nail down. Eventually, the cause of this freeze problem
was identified --- the default SACK feature (enabled) in the TCP/IP stack.