Measuring DRP-RTT in Cisco Distributed Director

[최창국]

In Cisco Distributed Director, measuring DRP-RTT is occurs between distributed servers and the client¡¯s local DNS. The reason of this is that there¡¯s no client¡¯s information(IP addr) field in DNS query to the local DNS. 
    I think the measuring way will work well. But latency between distributed server and the client¡¯s local DNS is different from it between distributed server and the client. I guess this difference can be big sometimes so that the client will be connected to worth server then the best server. 
    What I like to know is how I can measure the RTT between server and the client. (even though current measuring way doesn¡¯t be a serious problem in global point of view).
Do exist any solutions or hits for my purpose?

Thank you for your replying.