11.7 Telecommunications Management Network

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As companies seek to merge their networks and systems, they must consider how to manage heterogeneous environments of differing protocols, technologies, and legacy systems. Telecommunications management network (TMN) provides for more capable and efficient networks by defining standard ways of performing network management tasks and communicating across networks. As defined by the ITU, TMN is a set of international standards that enables telecom companies to save existing investments by integrating legacy systems and newer equipment from different vendors into the same network management infrastructure. When implementing theTMNdefinitions, telecommunications networks become interoperable, even when interacting with the networks and equipment of other telecommunications service providers. Ultimately, interoperability can be achieved across all managed networks.

TMN uses an object model to describe each network element (such as a frame relay switch or a fixed wireless base station) that is being managed. The object model facilitates the development of management applications that are independent of the implementation details of the network elements, making it possible to manage equipment from many suppliers with a single application.

An intelligent agent provides the means through which a TMN manager communicates and controls the network elements. The agent acts as an interpreter and filter for sending object-specific commands to the network elements it controls to get the data it requires. The agents send the collected information back to the manager. In turn, the manager may also act as an agent, collecting and filtering information for another higher-level manager.

11.7.1 Benefits of TMN

Telecommunications carriers today are faced with the task of rapidly introducing and managing new competitive services. To do this successfully, they must quickly integrate and be able to manage communications equipment from multiple vendors. Focusing on the communication of management information, the TMN framework fulfills this need and offers telecommunications carriers the following added benefits:

  • Cuts time to market for new services by separating the management model from the physical detail of the networked devices, allowing new services to be released without affecting the switching network.

  • Makes the network more robust by allowing network management to be distributed, while decreasing the amount of management traffic over the network. Protects existing investments in network equipment by allowing legacy systems and new systems to be integrated into the same network management infrastructure. Empowers telecommunications companies to be more competitive by allowing service, management, and accounting systems to be integrated, thus streamlining business processes and improving quality of service.

TMN is also applicable in wireless communications, cable television networks, private overlay networks, and other large-scale, high-bandwidth communications networks.

11.7.2 Standards

TMN consists of a series of interrelated national and international standards and agreements. The International Telecommunication Union-Telecommunications (ITU-T) began work on TMN in 1988. The ITU [formerly known as Consultative Committee for International Telegraphy and Telephony (CCITT)] extended the ISO/OSI standards for systems management by adding its own recommendations for architecture (M.3000 series), modeling (G series), and interfaces (Q series). The resulting standard M.3010 is the high-level specification of the framework, which provides for the observation, control, coordination, and maintenance of telecommunications networks. Since theTMNmodel is based on open interfaces, it is attractive to telecommunications operators and service providers as a way to solve common management problems without being limited by proprietary vendor solutions.

By making all internal network management functions available through standardized interfaces, service providers can achieve more rapid deployment of new services through maximum use of automated functions. Vendors of network elements can offer specialized management systems known as element managers, which can integrate readily into a service provider’s larger management hierarchy. Groups of service providers can enter into business-level agreements and deploy resource-sharing arrangements that can be administered automatically through interoperable interfaces.

Under TMN, management tasks are arranged into network element, element management, network management, service management, and business management layers. OSI’s Common Management Information Protocol (CMIP) is used to communicate between the adjacent layers.

Object-oriented techniques are used for creating data structures and their access methods for the MIB. Traditional manager/agent concepts are used for the hierarchical exchange of management information between systems. A MIB is located at an agent and provides an abstraction of network resources for the purpose of facilitating management. The agent provides service elements, which are a standard set of access methods into the MIB.

11.7.3 Functional Architecture

TMN breaks the tasks performed in a management network into the following functional blocks:

  • Network element function (NEF): Contains the telecommunications functions, which are the actual subject of management.

  • Operations systems function (OSF): Processes information related to management.

  • Workstation function (WSF): Provides the means to interpret TMN information for the management system operator.

  • Q adaptor function (QAF): Reconciles a non-TMN NEF or OSF to TMN via protocol conversion to a standard TMN interface.

  • Mediation function (MF): Mediates between a non-OSF and a NEF or a QAF and presents the information in a different form for the OSF.

  • Data communication function (DCF): Transfers telecommunication network management information.

11.7.4 Physical Architecture

TMN standards define two types of telecommunications resources: managed systems, generally known as network elements (NE); and managing systems, of which the operation system (OS) is the most prominent. TMNalso defines reference points (f, g, m, q, and x), which can exist between these functional blocks. Reference points become interfaces when they occur at locations that require data communications between network elements. The key interface in the TMN model is the OS-NE (or Q3) interface, which uses a CMIP manager/agent pair to provide access to a standardized MIB.

For each functional block, a physical block can be implemented, thus leading to a physical architecture. Reference points are a significant part of the TMN functional architecture and are realized within the physical architecture by physical interfaces within systems or equipment. The implementation of the reference points are represented by capital letters (Q, F, X) and form the common boundary between associated buildingTMNblocks. The F interface is found between workstations and the TMN; the Q (Q3) interface is found between TMN devices; and the X interface is found between the devices of one TMN and the devices of another TMN via the data communication network (DCN). Figure 11.5 describes the physical architecture, showing the implementation of reference points (i.e., interfaces) within TMN.

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Figure 11.5: Physical architecture of the TMN.

A telecommunications network provides voice and data services to customers; this function is outside of the TMN. However, the network consists of various network elements that can provide TMN functions and services. Central to the TMN is the DCN, which typically uses portions of the carrier’s telecommunication network to transmit management information. Telecommunications network NEs, which provide transmission to the DCN, are part of the TMN’s DCN.

Most NEs provide services such as environmental alarm notification or telecommunications transmission for a facility or a telecommunications network. NEs that provide a TMN management interface as well as non-TMN functions straddle the TMN boundary.

The operation system provides the mechanism for interaction, observation, and execution of many of the functions within the TMN. All higher level functionality, however, does not have to be physically located within the OS, NE, or any other single point in the TMN.

TMN elements use object-oriented techniques to represent resources under their control as managed objects. A common understanding of these objects is shared between the element that controls the resources—a mediation device (MD) or NE—and the manager of the resource, an OS or MD. As noted, TMN uses a manager/agent paradigm where the manager issues instructions and the agent carries out the instructions. In response to instructions to the agent, methods in the managed object are invoked, resulting in a variety of information storing, retrieving, and processing activities within the NE or MD. A NEF agent can be controlled either by an OSF or MD manager, but an MF agent is under the control of an OSF manager.

In sum, the ITU defined the TMN standards to facilitate the management of global telecom networks. The advantage of TMN is that it enables companies to integrate diverse network elements, including legacy systems and newer equipment, into the same network management infrastructure. TMN uses an object model to describe each network element being managed. The object model eases the development of management applications that are independent of the implementation details of network elements, such that a single application can manage equipment from many suppliers. Among the popular management platforms that support TMN are Hewlett Packard’s OpenView, IBM’s NetView, Sun’s Solstice Enterprise Manager, and Tivoli’s (an IBM company) Management Framework. The companies also offer TMN development tools that allow rapid integration of applications into TMN networks.



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LANs to WANs(c) The Complete Management Guide
LANs to WANs: The Complete Management Guide
ISBN: 1580535720
EAN: 2147483647
Year: 2003
Pages: 184

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