a) Describe and critically appraise how Network Management Systems have evolved to incorporate standards-based features such as the Telecommunications Management Network (TMN) and de facto SNMP elements. Include practical examples of management systems used at various TMN levels. EV 10 Marks b) How can various versions of SNMP and non-SNMP devices be managed by an SNMP Management system? Include how an NMS based on SNMP can communicate successfully with a relational database. CR 5 Marks c) Discuss the concept of Flow Management used in data networks. Define the unique keys used in this technology. Describe how flow management can assist network managers in identifying security problems encountered in the network.