Thanks for the insight., i was just testing it. Anyway guys I think i have found the solution of my problem let me share it for others as well.. if the traffic is tagged with priority on VLAN A then it will automatically be prioritized over the traffic of VLAN B. So flow control should be enabled on the frames that are being received on any ports. the frames should have the information so that the switch/VLAN recongnizes what to do with it.