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New Member

Point to Point Link Data Transfer

We have offices in two locations and they are connected through a 2Mbps IPLC link. We have ftp server in location A. When we are trying to upload a file to Location A from Location B we are getting an upload speed of 30Kbps. But we try to download a file from Location B to Location A we get a speed of 200Kbps. The end points in both the location is cisco 3640 Router. Can anyone advice me what could be the problem and how can i get the upload speed from location A to Location B more.

Thanks in Advance

New Member

Re: Point to Point Link Data Transfer

When downloading/using FTP, youre upp for TCP Window handling/handshake. Its TCP session that are limitation for youre FTP sessions. Try experimenting with diffrent size of TCP Window on your PC/Servers.

Re: Point to Point Link Data Transfer


I remember very stupid mistake in the past which behaved the same way. The cause was a forgotten "port storm-control unicast" command on a switch port.




Re: Point to Point Link Data Transfer

The receiver in the slow connection is probably not offering a big tcp window. I never have found a way to configure the window. It seems like some os'calc it based on available memory and others are fixed. Win98 uses 8k and later wins use 64k.

Now that I think about it I think there is a regedit that changes it in Win98. Don't know what your hosts are.


Re: Point to Point Link Data Transfer

30Kbps (bits) is down in modem territory. Did you mean 30KBps (bytes)?

Even 30KBps, though, is too low of a number to attribute to TCP windows unless the link's round-trip latency is on the order of 250ms (if an 8KB window is being used) or 2 seconds (with a 64KB window). So if you're not experiencing this level of latency (which seems high for a point-to-point circuit), your problem is elsewhere.

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