Hi
(Great program, by the way - very easy to set up... thanks !)

Out here in the wilds of South-West Ireland, our internet access is via a microwave link. Generally it's fine - but on FTP activity (uploading website files via FireFTP or the FTP prog in NetObjects Fusion) things go badly wrong - and the upload fails.

I contacted the people that run my servers - they suggested pinging a known location while running an FTP upload. The known location they suggested was their FTP server.

Taking it one step further <g> - I set up PP to do the pinging for me - and ended up with the attached image.

Watching it in realtime - when the FTP's playing up, starting an upload will cause the FTP program to complain that the link to the server has been lost - and the graph shows 'ERR' - as in the image...

FireFTP seems more resilient when 'passive FTP' is NOT checked - PP still shows slow hops and loss but the upload seems to get through. With Passive FTP selected the upload will fail on an error..

Any idea what I'm looking at here ?? I think that the hops in the '10.' series are the microwave link.....??

Thanks
Adrian

Your PingPlotter graph looks like classic bandwidth saturation. Upload bandwidth is usually a lot more limited than download bandwidth, and the symptoms I see in the graph are consistent with saturation.

The final destination, though, doesn't seem to be exhibiting the same problems - you turned off the time graph for the final destination, so it's hard to comment on that with too much authority, but it looks like maybe the packet loss and latency at the intermediate hops is a lot less than at the final destination. This indicates that an early hop is doing some prioritization of packets and TTL expired packets (intermediate hops in PingPlotter) might be getting a lower priority than FTP packets.

It's hard to know about the disconnect. If your FTP software is very latency sensitive, then I can imagine an uploading causing problems. FTP software, though, should not be very latency sensitive - just because the FTP protocol is so often used in situations where the bandwidth is saturated (since uploading and downloading at a maximum rate is so important for most users).

If you can easily reproduce the dropped sessions, I'd try to show your ISP how to do that - they may be able to do interesting things in solving the problem if it's easy for them to reproduce.