We have a VPN tunnel to another company and use it to move large files (20-100M). We are only able to achieve ~250kByte transfer speeds. The ping-time is ~250ms. We are using a 9M partial DS3 with a PIX 525 and the receive site has 100M burst capability (unsure as to the equipment on the rx end).
Yes, I have tried adjusting the RWIN during testing. No, the application is not able to create multiple send threads/streams. Is there a calculation to verify the transfer speed and factor the latency? What else could we look into to try and improve the tunnel speed?