How to identify what interface the client want to invoke by DCOM‘s request packet

I learn about the theory about communication of DCOM what is built on DCERPC. i am eagerto getting help from you. I would like to konw how to analysis of a request PDU of DCOM'S to get what the interface of the ORPC want to invoke （I find wireshark can do it）, by object UUID（IPID） or Context ID?