The BCL provides support for building on the COM+ services such as distributed transactions, JIT activation, object pooling, queuing, and events. The BCL also includes types that provide access to reliable, asynchronous, one-way messaging via an existing Message Queue infrastructure (MSMQ). The BCL also includes classes that provide access to existing directory services (Active Directory).

For more information, see the following namespaces:

Microsoft.ComServices
System.DirectoryServices 
System.Messaging
System.Messaging.Design