so. It does not have enough functionality to support advanced network management, Fundamentals of EMS, NMS and OSS/BSS 6.9 Overview of IIOP (Internet Inter-ORB Protocol) The definitions for IIOP were developed by OMG (object management group). IIOP specification consists of a set of formatting rules and message formats for communication in a distributed environment. In the distributed environment the client is isolated from the server by a well-defined interface. IIOP is an underly- ing mechanism of CORBA (common object request broker architecture) where CORBA specifications detail creation and use of distributed objects. CORBA and IIOP are inseparable and together form a solid framework for distributed comput- ing. The heart of this framework is the ORB (object request broker) that permits communication between applications in heterogeneous environments. The IIOP is an implementation of abstract protocol GIOP (general inter-ORB protocol) over connection oriented (see Figure 6.2) TCP/IP for use on the internet. GIOP definition has three parts: Common data representation (CDR): This defines a set of data formatting rules based on data types supported by CORBA IDL (interface definition language). Interoperable object reference (IOR): This defines a common format for objects to publish their identities while transfer of data using IIOP. The IOR usually contains the protocol version, server address, and an object key to identify the remote object. Message formats: This defines the messages exchanged between the agents and the manager using this application layer for management. Some of the messages are: Message Explanation Request Used to invoke a remote method Reply This is the response to a "Request" message LocateRequest Used to check if a particular address is supported or request on the address of the remote object Application objects TCP/IP Figure 6.2 Layered view showing where IIOP fits in. Management Protocols LocateReply This is a response to the "LocateRequest" and contains the address of the object, in cas