ged object (MO). OSI Network Management Label Start State Location Gateway Reboot No of connections Input format Signaling gateway Output format Signal format conversion Figure 5.5 Example of derived object. A sample Managed Object Template is given below: <class-label MANAGED OBJECT CLASS [DERIVED FROM <class-label>i] [CHARACTERIZED BY * ; ] [ATTRIBUTES ; ] [BEHAVIOUR * ; ] [NOTIFICATIONS *;] REGISTERED AS <object-identifier>; The managed object (MO) has ATTRIBUTES to define its static and dynamic properties, BEHAVIOR to represent the methods/actions performed by the MO and NOTIFICATIONS are for events. The class-label uniquely identifies the class and every managed object is to be registered as a unique object in the management information tree (MIT). The "registered as" part reg- isters the MO definition on the ISO registration tree. The "derived from" section describes the base class whose definitions are inherited by the MO child class. A sample of the managed object template is given in Figure 5.5. The "characterized by" part includes the body of data attributes, operations, and event notifications encapsulated by the MO. The SMI was introduced in ISO-10165 and it was elaborated in the guidelines for the definitions of managed objects (GDMO). The GDMO provides syntax for MO definitions. The GDMO introduces substantial extensions of ASN.I (abstract syntax notification) to handle the syntax of managed objects. The ASN will be covered in detail in the chapter on SNMP. 5.3.2 Management Information Base (MIB) MIB is a virtual database that contains information about managed objects. The information is organized in a treelike structure by a grouping of related objects and relationship that exists between them (see Figure 5.6). A managed object instance in the tree includes attributes that serve as its relative distinguishing name (RDN). The RDN attributes are used to uniquely identify the instance among the derivatives or children of the managed object. By concatenating RDN with the MIT path from Fundamentals of 