Two types of data structures are specified in this document: data structures that are specified in terms of the wire format and data structures that are RPC-marshaled as specified in [MS-RPCE]. The latter are specified by using the Interface Definition Language (IDL) that is defined in [MS-RPCE] section 2.2.4.
For some types of data, both formats are shown. For example, both formats are shown if some protocols use the raw wire format but other protocols use the RPC-marshaled format. Any protocol that uses a data structure name in its IDL necessarily implies the use of the IDL version of the data structure. Any other use implies the use of the wire format version unless otherwise specified by the protocol that uses the data structure.