An ObjRef is a serializable representation of an object,used to transfer an object reference across an AppDomain boundary.ObjRef contains information that describes the class and type of the Object being marshaled,its exact location and communication-related information.
All Marshal() methods return ObjRef object.The ObjRef is serializable because it implements the interface ISerializable, and can be marshaled by value. The ObjRef knows about :-
ObjRef is a searializable object returned by Marshal() that knows about location of the remote object, host name, port number, and object name.