he same time possi- ble to add ports manually from the NE screen. That is, in creating a port hierarchy, one is not confined to using only port templates or only manually entered ports. Templates are built up from the lowest level of the parent-child hierarchy, so that if child ports exist then they must be set up in a port template before the parent ports. Specifying a port range is a fast method for creating port templates that contain many records. This involves entering a range of sequential entries for a port tem- plate, rather than entering all port numbers individually (see Figure 11.35). Finally, CCM allows the building of SDH rings so that path diversity can be built in the network. 11.4 Conclusion No attempt is made to weigh the relative merits of the products CSM and CCM. The most important lesson from the approach taken by CSM is that it is possible to cus- tomise and automate configuration management. APIs allow extension of a base prod- uct ad infinitum. We have sought to remove the mystery for extensibility via APIs by providing a whirlwind tour through some of the classes and methods of the CSM API. We have sought to show what is involved in configuration management without requiring an understanding of particular network technologies such as Code Division Multiple Access (CDMA) or GSM for wireless and GigE, SDH or ATM for optical. Discussing details of network technologies in the context of configuration management only makes sense if we are to talk about the particular SNMP or TL1 commands that are to be sent to NEs. Such commands differ between network tech- nologies and between network technology implementations. Configuration management goes to the heart of network management OSS for telecom networks because it is about the collection and manipulation of data on network state and it is about the modification of network state. As NEs become more intelligent, configuration management will become increasingly central to telecom operations. In a sense, configuration management is about the manage