Telecommunication Management Network

Definition : The Telecommunications network (TMN) provides a framework for achieving interconnectivity and communication across heterogeneous operating systems and telecommunication networks.

TMN was developed by the International Telecommunication Union (ITU) as an infrastructure to support management and deployment of dynamic telecommunications services.


TMN Architecture

The interface points between the TMN and the telecommunication network are formed by Exchanges and Transmission systems . For the purpose of management, these Exchanges and Transmission systems are connected via a Data Communication Network to one or more Operations Systems . The Operations Systems perform most of the management functions. These functions may be carried out by human operators but also automatically. It is possible that a single management function will be performed by multiple Operations Systems. In this case, the Data Communication Network is used to exchange management information between the Operation Systems.


Basic Logical layers

At the border between Layer 1 and 2 the management view of Layer 2 is presented to Layer 1; this view is presented in the form of management information that is contained within the agent at Layer 2. Note that the management view that is presented to layer 1 need not unveil all details of layer 2; the agent at layer 2 will only provide those pieces of management information that are necessary at layer 1. The principle of layering can be applied in a recursive fashion; the management view of Layer 3 can be presented to Layer 2 etc.


Layers of Abstraction

Element Management Layer

The functions of individual Network Elements are managed by Operations Systems Functions (OSF) in the Element Management layer. This layer deals with vendor specific management functions and hides these functions from the layer above, the Network Management layer. Examples of functions performed at the Element Management layer are:
            –Detection of equipment errors,
            –Measuring power consumption,
            –Measuring the temperature of equipment,
            –Measuring the resources that are being used, like CPU-time, buffer space, queue length etc.,
            –Logging of statistical data,
            –Updating firmware.

Network Management Layer

Whereas the responsibility of the Element Management layer is to manage NEFs implemented within single pieces of equipment, the responsibility of the Network Management layer is to manage the functions related to the interaction between multiple pieces of equipment. At network management level the internal structure of the network elements is not visible; this implies that buffer space within routers, the temperature of switches etc. can not be directly managed at this level. Examples of functions performed at this layer are:

            –Creation of the complete network view,
            –Creation of dedicated paths through the network to support the QoS demands of end users,
            –Modification of routing tables,
            –Monitoring of link utilization,
            –Optimizing network performance, and
            –Detection of faults.


FCAPS

FCAPS (fault-management, configuration, accounting, performance, and security) is an acronym for a categorical model of the working objectives of network management. There are five levels, called the fault-management level (F), the configuration level (C), the accounting level (A), the performance level (P), and the security level (S).

At the F level, network problems are found and corrected. Potential future problems are identified, and steps are taken to prevent them from occurring or recurring. In this way, the network is kept operational, and downtime is minimized.

At the C level, network operation is monitored and controlled. Hardware and programming changes, including the addition of new equipment and programs, modification of existing systems, and removal of obsolete systems and programs, are coordinated. An inventory of equipment and programs is kept and updated regularly.

The A level, which might also be called the allocation level, is devoted to distributing resources optimally and fairly among network subscribers. This makes the most effective use of the systems available, minimizing the cost of operation. This level is also responsible for ensuring that users are billed appropriately.

The P level is involved with managing the overall performance of the network. Throughput is maximized, bottlenecks are avoided, and potential problems are identified. A major part of the effort is to identify which improvements will yield the greatest overall performance enhancement.

At the S level, the network is protected against hackers, unauthorized users, and physical or electronic sabotage. Confidentiality of user information is maintained where necessary or warranted. The security systems also allow network administrators to control what each individual authorized user can (and cannot) do with the system.


Service Management Layer

The Service Management layer is concerned with management of those aspects that may directly be observed by the users of the telecommunication network. These users may be end users (customers) but also other service providers (administrations). Service Management builds upon the management information that is provided by the Network Management layer, but does not `see' the internal structure of the network. Routers, switches, links etc. can therefore not directly be managed at Service Management level.


Business Management Layer

The Business Management layer is responsible for the management of the whole enterprise. This layer has a broad scope; communications management is just a part of it. Business management can be seen as goal setting, rather than goal achieving. For this reason business Management can better be related to strategical and tactical management, instead of operational management, like the other management layers of TMN.

References

http://etutorials.org/Networking/network+management/ 
http://www.simpleweb.org/tutorials/tmn/