Today's enterprise information systems are modeled on the client/server paradigm over LANs interconnected by WANs, but it involves problems of network management costs and complicated management jobs. So efficient network management is strongly required for LANs interconnected by WANs. In this paper, we describe a hierarchical enterprise network management system for LANs interconnected by WANs, based upon analysis of LAN management operations. This network management system has a hierarchical model with three levels, i.e., center level, area level, and user-site level. We also describe how this system was implemented as a nation-wide corporate network with many LAN sites, emphasizing on its functional structure. This network's success has confirmed usefulness of the management system.

In the future PCS (personal communication system), it is needed to use wireless and wired resources most efficiently, because of the increase of users and various multimedia traffics. Therefore, there have been much researches on CDMA (code division multiple access) whose frequency reuse is most efficient. Here, if one of PCS subsystems is broken down because of system, power, or network failure, it is impossible to serve PCS user terminals anymore. To solve this problem, the integrated network management function is required to examine each subsystem periodically or non-periodically, and handle each error properly, and inform network manager or PCS service management center of error occurrence. In this paper, we consider standard SNMP (simple network management protocol) and CMIP (common management information protocol) as the management protocol of PCS land mobile network. Also, we present the overall structure of management information taking CDMA PCS characteristics into consideration. Since there were little considerations for characteristics specific to cellular environment in the conventional network management systems, we add the CDMA PCS-specific management informations to each agent systems. Thereafter, we present the optimum network management protocol stack for PCS environment which provides TMN (telecommunications management network) interfaces among each subsystems as well as including wired networks.

As enterprises use ATM networks for their private networks and as these private networks use public ATM networks for wide area communication, the need for the customers to be able to manage both private and public networks is increasing. Currently, some standardization work is being done towards providing this capability to customers. In this paper, we propose a new customer network management (CNM) system architecture for the management of both private and public ATM networks in a uniform way. The particular features of the proposed architecture lies in the efficient support of the complex hierarchical TMN manager-agent relationships at M3 and M4 interfaces, and the support of SNMP and CMIP integration. The TMN hierarchical many-to-many manager-agent relationships are realized by the utilization of a CORBA-based Shared Management Knowledge (SMK) system. We have implemented a prototype of ATM CNM system, and measured the performance for the demonstration of the suitability of the proposed architecture.

This paper reviews the business reasons why telecommunications service providers and network operators are moving to standardise key aspects of the management of their networks and services, and how the international definition of the Telecommunications Management NetworkTMNfits within current business strategies. It discusses the potential benefits of TMN implementation as well as some pitfalls that must be addressed in order to gain its full potential, including the technical evolution of the TMN framework to take advantage of advances in distributed object-oriented computing. TMN had its beginnings prior to the commercial and regulatory upheaval that now rocks the telecommunications industry world-wide. The focus of investment-toward a lean, competitive positionrepresents a significant change from the days when TMN was first beginning to be defined. This shift in emphasis, from a network-centric view to one that recognises the value of fast, accurate customer response and operational efficiency, has heightened the need for a standard way of managing within companies and across company boundaries. TMN is the best model the industry has for achieving standardisation. But the TMN model, in order to really meet the needs of industry going forward, must be interpreted more broadly than it has been in standards. We do not argue that TMN is in any way wrong, indeed we applaud the progress made to date.

This study clarifies the effects of network complexity and network map transformation on the ability of network managers to use graphic network displays. Maps of Japan and the United States with outlines of their respective prefectures or states were displayed on a CRT. Each map displayed a fictitious network of nodes and their interconnections. These networks were two-level hierarchical and non-meshed, meaning that each low-level node was connected to a single high-level node, but not all high-level nodes were linked together. The subjects, task was to identify a path between two low-level nodes. In each trial, two low-level nodes were highlighted, and the subject attempted to find the shortest path between these nodes. This was done by using a mouse to select intermediate nodes. Completing a path required a minimum of 4 node traversals. Three variables were manipulated. First, the number of nodes was defined as the total number of low-level nodes in a network (70, 150, or 200). The second variable was the level of transformation. Very densely populated areas of the maps were systematically transformed to reduce congestion. There were three levels of transformation. The final variable was the country map used, that is, the map of Japan and the map of the United States. Several behavioral measures were used. The most informativ. appeared to be the time required to complete a path (the response time), and how often subjects returned to previous portions of a path (back-ups). For both of these measures, the data pattern was essentially the same. Increasing the number of nodes hurts performance. This was particularly pronounced when the map of Japan was tested. However, as the level of transformation increased, this effect was substantially reduced or completely eliminated. The results are discussed in terms of engineering rules and guidelines for designing graphical network representations.

The up and coming multimedia services are based on real-time high-speed networks. For efficient operation of such services, real-time and precise network management is essential. In this paper, we show that presently available MIB designs are severely inadequate to support real-time network management. We point out and analyze the management constraints and bottlenecks. The concept of quality of management of management information is introduced and its importance in practical network management is discussed. We have proposed a new MIB architecture that will raise the quality of management information to meet the requirements of managing high-speed networks and multimedia services. Experimental results from a prototype implementation of the new MIB architecture are presented.

Intelligent Network (IN) is a distributed architecture allowing telecom companies to create and to customize services. Network and services have to be integrated in the management process provided by the IN. The integration of the Intelligent Network and the TMN (Telecommunications Management Networks) can be useful to achieve the management process. Our proposal is an evolution towards a more intelligent management structure provided through the Distributed Artificial Intelligence concepts.

We propose a new concept of network dimensioning, which is based not only on the grade of service but also on profit. In traditional network dimensioning methodology, the number of circuits on links is designed under a cost-minimization concept with grade of service constraints. Recently, telecommunication markets have become very large and competitive; therefore, we believe that a profit viewpoint is now essential. However, it is difficult to calculate profit in almost all the dimensioning methods currently used, because they mainly employ peak-hour traffic data, while profit depends on all the hourly traffic data which contain both peak and off-peak data. In this paper, we propose using all the hourly traffic data in network dimensioning. From these data and telephone charges for each hour, revenues will be estimated. On the other hand, facility costs will be estimated from the number of circuits. Finally, we can estimate profit from the difference between revenues and facility costs. Focusing on both quality and profits in network dimensioning leads to more advanced quality management and quality control in telecommunications networks than with traditional methodology. This paper outlines a dimensioning method based on profit, and describes its properties, some applications of it, and summarizes further studies.

The availability of new technologies in the computer and network industry has allowed us to benefit from a wider choice when building new information systems. This paper presents Japan Airlines' challenge to develop a new information network and management infrastructure based on the new technology. Compared with the existing main-frame environment, the new infrastructure will give us a more comfortable and economic network computing environment. Once we think about network management, there are so many issues to be solved. All existing network elements have their own management consoles with different interfaces and commands. Net managers are swimming in the pool of system consoles looking for the one that exactly tells them what is going on at the user site. The industry standard SNMP offers us a much better environment. However, there is still a long way to go before reaching a world where net managers find a single management console with a single object to manage that is composed of all network elements.

Trouble management is a key function in solving the problems and maintaining the high communications capability of a network when communication service network users encounter problems in the quality of services [1]. This paper proposes technologies and architecture for an intelligent management system to achieve advanced service/network trouble management. The system generates operation scenarios to find a cause to solve a reported trouble, executes them, and modifies them according to operation circumstance changes. In the scenario execution process, fault propagation simulation is used to isolate a fault in necessary cases. The evaluation of the system applied to the ISDN services shows that the proposed system can achieve high-speed, precise trouble management by the integrated cooperative work of a human (operator) and a machine (operation system).

This paper proposes a new approach to the management of large-scale communication networks. To manage large-scale communication networks effectively, it is essential to get a bird's-eye view of them when they are in their normal conditions. When an indication of faulty state is detected, the focus of the management is narrowed down to the faulty network elements until the appropriate granularity is reached. This management scheme is called multilevel network management in this paper, and it first explains the significance of this scheme for large-scale communication networks and presents some ideas on implementing this management scheme. It then proposes that system identification be used in multilevel network management. The system identification is used to measure transmission delays between two arbitrarily selected nodes in the networks, and multilevel network management is achieved by selecting those two nodes appropriately in accordance with the levels to be managed. Finally, it is demonstrated by computation simulation results that the proposed method is suitable for multilevel network management.

This paper proposes a suitable distributed computing model as the basis for building a network management system. Author has been studying a distributed reactive model, called Meta for this purpose at Cornell University. Effectiveness using Meta is to provide high level program interface for developing network management system, and programmers can achieve network management system with coding small amount of programs. It also realizes easy additions and modifications for network management application programs. To confirm the effectiveness of the proposal, the author has utilized Meta to implement an experimental network management system. The experimental system provides high level interfaces for monitoring and controlling network components. It also supports reliable communication over distributed nodes. Preliminary evaluation of the system shows that critical network management applications are provided within an appropriate response time for all applications provided by SNMP, with small development cost and easy system modification.

This paper discusses a way of identifying the network configuration of ATM-LANs, which are composed of a number of ATM hubs. In general, a Network Management System (NMS) sets and gets the necessary data to and from the network elements. In managing an ATM-LAN, the ATM connection between the NMS and each network element, namely the ATM hub, must be established in order to get and set the necessary data. This forms a remarkable contrast with conventional LANs such as the IEEE802.3 LAN, which is a shared media network and enables broadcast communication without setting up any connection. This paper proposes a new protocol and a procedure that establishes the ATM connection between the NMS and each ATM hub, while identifying the overall network configuration. First, this paper makes clear the peculiarity of the ATM-LAN in terms of automatically identifying the network configuration. Next, the identification protocol that achieves the required properties is precisely explained. Then, the proposed identification protocol is evaluated in terms of required bandwidth and identification time.

Asynchronous Transfer Mode (ATM) is an information transport technique that well supports Broadband ISDN (B-ISDN). One unsolved problem to the perfection of ATM networks is to provide a testing environment that conforms to some standardized network management scheme. From this point of view, remotely controlled virtual path testing is considered in this paper. Remotely controlled virtual path testing should be executed through the standardized Telecommunications Management Network (TMN) model, which employs the OSI systems management concept as the basis of information exchange. Thus, this paper addresses the two issues that arise when OSI systems management standards are applied to virtual path testing. One issue is to define relevant information models. The other issue is to provide test resources with a concurrency control mechanism that guarantees a consistent test environment without causing deadlocks. To resolve these issues, technical requirements are clarified for the remote control of test resources. Next, alternatives to the concurrency control mechanism are shown and compared through computer simulations. A method of defining information models is then proposed. The proposed method ensures the easy storage and retrieval of intermediate test results as well as permitting the effective provision of concurrency control for test resources. An application scenario is also derived. The scenario shows that tests can be executed by using standardized communication services. These results confirm that virtual path testing can be successfully achieved in conformance with the OSI systems management standards.

As the size and complexity of network increases, the distributed systems management (DSM) will be vital in order to improve the availability of network management, to reduce the complexity of network operations, and to provide the high reliability. In this paper, we (1) describe general requirements required for systems management in distributed environment, (2) introduce the basic structure of distributed network management system (DNMS) for efficient network management, and also especially illustrate the concrete design of system management application process which is an important element among them, (3) propose the connectionless CMIP to accomplish for effectively managing the distributed management system, and indicate its efficiency; this protocol is available to manage dynamically changing DSM environment, to negotiate among the managing systems, to handle the dynamic informations etc. Finally, (4) the behavior and software structure of a suggested management system during negotiation to execute the received request for implementation are presented.

In this paper we examine the architectural and operational design issues of a practical network management system using the Simple Network Management Protocol (SNMP) in the context of a large-scale OSI-based campus-network TAINS. Various design aspects are examined and the importance of time-management is elicited. In the proposed design, intelligent, time-synchronised agents are deployed to collect information about the network segments to which they are attached. The manager talks to the agents and gathers relevant network information. This information is used by the expert network manager, in conjunction with a network knowledge base (NKB) and a management information knowledge base (MIKB) , to reconstruct the overall network-traffic characteristic, to evaluate the status of the network and to take/suggest some action. This model is particularly useful in networks where some global control, monitoring and management is desired and installing agents on all elements, connected to the network, is impossible. The use of time labels and narrow time windows enables the manager to obtain a reasonably accurate picture of the network status. The introduction of time-labelled composite objects in the Management Information Base (MIB) provides a means of reducing the load of management-related traffic on the network. The MIKB containing a logical description of the behaviour of the managed objects defined in the MIB, drives the expert system and provides the knowledge of general nature that a human expert has about networks. The proposed MIKB concept provides a very convenient schema for building the knowledge base in an expert network management system. Further since the MIKB is MIB-specific, it can be used in network management systems for managing similar MIB's.