Quality of Service (QoS) mechanisms provide the necessary level of services (bandwidth and delay) to any application in order to maintain an expected quality level. This paper studies the effect of adopting QoS on the performance of (real time) system like video conferencing. A simulation model of the real time network is built using OPNET package. The various parameters affecting the system performance are determined and different solutions to enhance the system performance are suggested .A modified switch architecture is proposed to enhance the real time performance of the system and to modify its quality of service capability .The modification includes adding Etherchannel unit which can classify data into real time or non-real time data and direct each data packet to the appropriate channel .The architecture of the Etherchannel unit is described by VHDL programming and built on FPGA chip .Accordingly , the modified switch is found to need only extra seven clock pulses to classify each data packet .
Keywords: Quality of Service (QoS), Switched Ethernet, UDP, TCP, FPGA,VHDL