ement entity or man- ager (TM system). They can be routers, access servers, switches, cross-connects, computer hosts, etc. Each managed device has an agent. The agents are software modules residing in a managed device that handle local management information within the device. Managed devices can contain several managed objects. Hardware, configuration param- eters and statistics can be managed objects, if referring to the IETF definition. Managed objects are directly related to the operation of the device. They are arranged in a virtual information database called a management information base (MIB). See Figure 16.6. The manager or management entity executes applications monitoring and controlling managed devices. Management entities provide most of the processing and memory resources required for network management. C++ is used for 'agents' and 'managers' programming. CORBA is a standard for 'managed object' definition and all-to-all manager-agent communication. It is well suited Telecom Management - Operations Management entity TM-MIB Agent Agent Agent Management Management Management database database database Managed devices Figure 16.6 TM basic structure for distributed systems running on different platforms (even written in different languages). This feature opens the possibility to integrate different vendor equipment and management systems in a managed network. CORBA has a drawback, though: the managed object definition is not fully compatible with TMN and IETF definitions. CORBA can be seen as a 'software bus' used by clients and servers. All CORBA objects are described in an interface specification enabling other objects to communicate with them. It is used in OSS components handling traffic measurements, charging etc. SNMP is a very simple protocol. It has a short list of commands, which basically are only read or write. It is used just for communication or data interchange between the managed objects in the management information base and the management entity (or manager). The job to translate the i