This is answer my own question.
By the simple test, I got to know that iperf server application do not take the one of serperated interface until the interface linked by the link partner, that means when running iperf client from peer device, iperf client will assign IP as same as one of IPs n the server(gateway IP or the client IP against Joined AP),
at this moment seperate iperf port also be assigned for each interface running on the iperf server device.
In the wiced(iperf server side) to take the serperate interface, two iperf server instance should be run for each interface
coummunication and the port should be seperated as same as client ports.