Transmitted Pause Frames

Hi all, can anyone give me a little insight on "Transmitted Pause Frames"?  I am seeing this counter increment on my two 5448's on the two ports that take iSCSI traffic to one of my MD3000i SANs.  The weird part is that it is only happening when I do a hot backup of an Oracle database using Backup Exec's Oracle Agent.  All other backups and normal traffic to the same SAN do not cause this to increment.  I am getting lousy throughput on the backup, and also seeing a large percentage of dropped frames on the MD3000i during the same Oracle Backups. 

I put another post in the PowerVault forum, but noticed the Transmitted Pause Frames doing this, so I thought I would seek council here as well.  To the very best of my understanding, the MD3000i, the server NICs, and the PowerConnect switches are all set up in accordance w/ Dell's best practice docs.  Jumbo MTU on all devices, flow control on, pre-made CAT6 cabling, 1000 full, etc.

I haven't been able to find much on this particular counter.  I understand its meaning in principal I think...  Something somewhere is getting overwhelmed and slowing down traffic...  but haven't quite determined if it means that the switch is the origination point for the TPF's, or if the counter simply means that a TPF was passed through.

Many thanks!