tionship between TMN interfaces and reference points is shown in Table 8.3. Legacy systems are not TMN compliant and mainly understand ASCII and are usually proprietary. A Q-Adaptar can be used to translate between CMIP and proprietary interfaces and can also be used to integrate enterprise network into the TMN infrastructure. 8.3.3.2 TMN Management Layers TMN also has a logical layered architecture that divides the management functions into logical layers and describes the relationship between these layers. A logical layer reflects particular aspects of management and implies the clustering of management information, supporting that aspect. A possible five TMN layer architecture defined in M.3010 is shown in Figure 8.18(a) [3,25]: Network Element Layer (NEL) performs basic management function for wireless equip- ment, such as detecting faults and counting errors. It provides the agent service functions in support of management request from the EML. Element Management Layer (EML) manages each network element on an individual or group basis and supports an abstraction of the functions provided by the network element layer. Its key functions are: Control and coordination of a subset of the network on an individual network function basis. Control and coordination of a subset of the network elements on a collective basis. Maintenance of statistical log and other data about network elements. Core Networks and Operations Support Systems Business Management Service Management Network Management Element Management Service Provider Figure 8.18 (a). TMN management layers. (b) TMN setup example Network Management Layer (NML) has the responsibility for end-to-end management of a network. It is also responsible for providing network functions such as network traffic monitoring, network protection routing and fault correlation and analysis from multiple network elements. Service Management Layer (SML) is responsible for the contractual aspects of services that are being provided to the customers. The key roles of SML are inter