bringing back the faulty NE back into working condition. The generation of the performance behavioural reports of the network and its elements is done by the performance management function of the network. And finally, prevention and detection of misuse of the network from breaches of security is taken care of by the security management function of the NMS. Network management functionality is based on master-slave protocols, and planning of the network management system starts with the choosing of the master. The NMS can act as the master and the NEs as the slave. Sometimes, network elements such as the base station controller or the base stations can also be the master. Once the master is defined, the management bus and its transfer method is decided. Then the next step is to decide the parameters for each of the network elements that the master will control. Each master that is chosen has its own capability of managing a number of network elements. The capacity may vary from managing just a few NEs to hundreds of NEs. Apart TRANSMISSION NETWORK OPTIMISATION from that, each master has its own speed of managing the elements; i.e. the speed of the management buses may vary in the network. These management buses may have a speed of 1200 bps, 9600 bps or even higher. Definition of the management bus includes deciding the NEs that will be engaged by a particular network element. Also, the topology of the management bus and the protection scheme that is associated with it are decided. One thing to remember is that the higher the number of elements associated with the management bus, the slower will be the speed of the bus. Network elements can be managed by attaching the slave to masters through a cable. Other techniques involve sending the managements bits through the PCM signal from TSO to TS31 and through the auxiliary data channels of frame overhead (of for example radio frames). Engineers need to define parameters such as the addresses of the NEs along with their identifications, and the speed to the management b