1 Apr 09 18:42
Work = 10Mbps QMOE (Qwest Metropolitan Optical Ethernet)
Home = 1.5Mpbs/896Kbps Qwest DSL
VPN connected, can ping IP's both ways
File = Windows2003SvrR2Sp2x32Disk2.iso (123,852KB)
First check was run with Ixia's QCheck monitor, it reported that work to home is 1.2Mbps and home to work is 708Kpbs. That fits with what my home DSL circuit should be showing.
Given those speeds, I should be able to download something from work theoretically at 192KBps (1536Kbps or 1.5Mbps), so a file that is 123,852KB should take 645 seconds or ~10.75 minutes. I verified that by transferring a file via FTP from work to home and it took around 15 minutes to transfer.
Please double check my math and make sure I did those conversions properly.
Now for the weirdness...
I set up a Windows based iSCSI target on a VM running at home. I used the Windows iSCSI initiator on a VM at work to connect to the iSCSI target at home over the VPN.
I then copied and pasted the same 120MB file from the VM here to the iSCSI connected drive that lives at home. It took 20 seconds for it to transfer. I verified this by connecting to my home VM and looking at the drive. Sure enough, there sat the file, I opened it and was able to view/access everything in the file.
How was this possible? Does iSCSI use some sort of voo-doo quantum mechanics magic to get the file there? It would seem to me that my file transfer speed is what it is and it should not matter if I'm transferring a file via HTTP, FTP, SCP, or across a windows share to an iSCSI target. It should only be able to move the file at it's max limit of 1.5MBps. Moving that 123,892KBps file in 20 seconds translates to 6,194KBps or 49,556Kbps (49Mbps). So how does a 1.5Mbps connection move a file at 49Mbps?