1.4 Relationship to Other Protocols
The COM+ Event System Protocol uses DCOM [MS-DCOM] to communicate over the wire and authenticate all requests issued against the infrastructure. Along with DCOM, this protocol also uses the OLE Automation Protocol [MS-OAUT] by using datatypes BSTR and VARIANT from the IDispatch interface.
The protocol described in [MS-COMA] can be used to perform the registration of type libraries for event classes and subscriber DCOM components used by the COM+ Event System Protocol. It can also be used to discover subscriber DCOM components registered on the server to create subscriptions.