PDF of this tutorialThe TMN architecture is a reference model for a hierarchical telecommunications management approach. Its purpose is to partition the functional areas of management into layers. The ITU–T defined the TMN architecture in 1988 and it is described in Recommendation M.3010 and other documents.
The key benefit of this architecture is to identify five functional levels of telecommunications management: business management layer (BML), service management layer (SML), network management layer (NML), element management layer (EML), and the (increasingly intelligent) NEs in the network element layer (NEL). TMN segregates the management responsibilities based on these layers. This makes it possible to distribute these functions or applications over the multiple disciplines of a service provider and use different operating systems, different databases, and different programming languages.
TMN calls for each layer to interface with adjacent layers through an appropriate interface to provide communications between applications, and as such more standard computing technologies can be used. The TMN M.3010 document allows for the use of multiple protocols. This means that open standards such as SNMP and CORBA are consistent with the TMN framework.
Figure 2. The Five-Layer TMN Network Management Architecture
As seen in Figure 2, the TMN model is simple but elegant and has been effectively used to represent the complex relationships within network-management architectures graphically. Originally based on common management information service element (CMISE), the object-oriented technology available at the time of inception in 1988, the model now demonstrates its flexibility with the recent adoption of technologies such as common object request broker architecture (CORBA), as we drive toward a more generic data-processing type of computing. This evolution of CORBA progressed in much the same way as SNMP led its generation of protocol adoption.
EMSs should, by strict adherence with the TMN model, communicate with their NEs by using the common management information protocol (CMIP). This, however, takes no recognition of the fact that most devices deployed in the marketplace use other protocols such as TL1, SNMP, and a variety of proprietary mechanisms. An efficient EMS communicates with its NE using whatever protocol is native to the NE. The effective EMS will also communicate with other higher-level management systems using protocols that are the most cost-effective to implement. Therefore, the TMN layering is achieved by using whatever protocols are appropriate.
