Marshaling by value is analogous to having a copy of the server object at the client. Objects that are marshaled by value are created on the remote server, serialized into a stream, and transmitted to the client where an exact copy is reconstructed. Once copied to the caller's application domain (by the marshaling process), all method calls and property accesses are executed entirely within that domain.
Marshall by value has several implications; first, the entire remote object is transmitted on the network. Second, some or the entire remote object may have no relevance outside of its local context. For example, the remote object may have a connection to a database, or a handle to a window, or a file handle etc. Third, parts of the remote object may not be serialiazable. In addition, when the client invokes a method on an MBV object, the local machine does the execution, which means that the compiled code (remote class) has to be available to the client. Because the object exists entirely in the caller's application domain, no state changes to the object are communicated to the originating application domain, or from the originator back to the caller.
MBV objects are, however, very efficient if they are small, and provide a repeated function that does not consume bandwidth. The entire object exists in the caller's domain, so there is no need to marshal accesses across domain boundaries. Using marshal-by-value objects can increase performance and reduce network traffic, when used for small objects or objects to which you will be making many accesses.
Marshal by value classes must either be marked with the [Serilaizable] attribute in order to use the default serialization, or must implement the ISerializable interface.
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