guration, for example loading a predetermined configuration down to the elements depending on the time of day. This level helps in maintaining an inventory of the network resources and for updat- ing the trouble tickets database, which contains information on the date and time of a fault, what action was taken to correct it and who took the action. This database is used by the next level manager, at the network level. The prime function of the network level manger is to maintain a network level view of the system being managed and to carry out Figure 16.5 Traffic volume trends on a network network wide tasks, such as setting up a service path between two elements on the network. Whereas the element level manager deals with problems associated with faulty equipment, the network level shows a trend curve of traffic demand, from which the operator manager is concerned with items such as traffic congestion and would deduce that capacity will need to be expanded after 1993 and throughput on the network. that a major re-design would be required by 1995, assuming that The service level manager manages the services which are carried occasional overloads before then are acceptable. over the network, for example an X.25 service, and it deals with faults which result in end customer complaints. A fourth level of management is also sometimes included, the business level man- 16.5 Trends in network management ager. It is here that the plans for the overall network are formulated, bearing in mind the present and predicted aims of the organisation. Figure 16.6 illustrates some of the trends in network management It takes a longer term view in considering items such as capacity and systems. The network management process, which currently has to growth, and costs in terms of inventory, operations and damage to be known and closely controlled by the user, will in future be the company and its reputation caused by downtime or congestion. transparent, so that the overall job is greatly simplified. The re- IN THE FUTURE KNOWN BY USER