Tsuneo Katsuyama

Policy Verification and Validation Framework Based on Model Checking Approach

Policy-based management is drawing attention as a solution to managing todays complex information systems. To be dependable, a policy-based system must be able to check the validity of a policy written by administrators. However, common test methods such as operations tests in a test scenario and simulations cannot check whether systems with given policies will work properly in every possible situation. To solve this problem, we propose a policy verification and validation framework based on model checking that exhaustively verifies a policys validity by considering the relations between system characteristics and policies. We first define the validity of policies and the information needed to verify them from the viewpoint of model checking. We then construct our policy verification framework based on the definition and, finally, present a case study applying this framework to an on-demand data center scenario and show the effectiveness of our approach.

NEPRI: available bandwidth measurement in IP networks

To provide a consistent quality of service in IP networks, it is necessary to know the current performance and available bandwidth of the network adequately. There are some ways to obtain the current available bandwidth such as management information base (MIB) analysis and RMON monitoring. The measurement methods using probing packets are studied, but they require a large number of packets to be transmitted in order to improve the measurement accuracy. They create heavy network traffic, so it is difficult to use such methods for actual networks in use. To solve the problem, we propose a new method called NEPRI. This method detects the macroscopic behaviour of the probing packets queued at the bottleneck and estimates the available bandwidth of the path. We show our method consumes less network resources and is sufficiently accurate.

Communication workstations for B-ISDN: MONSTER (multimedia oriented super terminal)

The authors describe the human interface for broadband multimedia communication services to be provided for use with the broadband integrated services digital network (B-ISDN). The basic architecture of a B-ISDN terminal called MONSTER (multimedia oriented super terminal) for realizing the human interface is also described. This terminal can transfer multimedia data at a rate of 150 Mb/s and process them in real time.<<ETX>>

Issues of Service Innovation and Its Model

This paper addresses service innovation. First, issues characteristic of services are studied from multiple perspectives. Then we present a model for service innovation, which is a plan-do-check-act cycle to improve services by making use of technologies. We take a close look at the model with a case study.

An Efficient Failure Recovery Scheme for Next Generation Network Services Based on Distributed Components

With advances of information and communication technologies, many network services can be provided by assortment of desired components running on some nodes in the network, like a distributed component based service. It is effective to reduce the cost of service development. In addition, when a failure occurs, a distributed component based service has multiple components of each function, which can be used to replace the failed component. There is another problem, however a component failure affects the application servers using it. Therefore, in this paper, we propose a novel failure recovery scheme that constructs overlay networks between components having the same function and that provides an efficient search method for the substitute component using these multiple overlay networks. Finally, simulation experiments demonstrate the excellent performance of the proposed scheme.

Multilayer failure detection method for network services based on distributed components

Network services based on distributed components, which provide advanced network services with lower cost by assigning and reusing useful components running on remote nodes, are attracting increasing attention. In this service, when a component fails, a component that has the same function running on another node can be substituted for it. On the other hand, there are three kinds of failures in network services; a software failure at a component, a hardware failure at a node, and a failure of the physical network. We propose a new method to identify a failure in network services, which determines not only a failure at the application level but also in the network layer by collecting a small number of messages via multiple overlay networks.

Constraint Verification for Concurrent System Management Workflows Sharing Resources

Workflow is an effective way to define and specify the behavior of autonomic systems which manage themselves. However, when a system is working following several workflows sharing resources, it is very difficult to analyze the behavior of the systems with mutual influences between workflows due to the shared resources, and to decide whether problems may be caused by such mutual influences, despite the need to do so in order to develop trustworthy autonomic systems. To solve this problem, we developed a verification framework to identify whether constraint violations could occur in a system working and following workflows sharing resources. In this paper, we initially define the system management workflows. Next, we show the procedure to translate these workflows into hybrid automata, with the mutual influences between workflows taken into consideration. Finally, we show how to detect possible constraint violations by adopting a model checking technique to the hybrid automata through a case study.

Integrated Digital Switching System with Queueing Storage Facility

This paper outlines the features of a new integrated switching system for voice and data. It is composed of integrated subscriber terminals, integrated subscriber lines, an integrated digital switching system, and integrated storage facilities. This paper shows that the introduction of the integrated storage facility can create various new service utilities and improve the traffic capacity of the system.

Dynamic reconstruction of multiple overlay network for next generation network services with distributed components

Because of rapid improvement in information and network technologies, many kinds of network services are created. In this paper, the concept of a new service platform is presented. Services are organized by components, and replications of components are distributed to many computers. Thanks to these replications, users can continue services by using another component as a substitute in case of failure. It is necessary to ask another component to fnd a substitute when a component fails. However, depending on which component to ask, the original version of the proposed method has a possibility to find only low-performance components. It is caused by constructing overlay network only once and keeping it as it is. We propose a new dynamic reconstruction method for overlay networks. Simulation experiments show how proposed method improves performance of our framework.

Applying Autonomic Computing with Open Standardized Resource Interface WSDM to Managing Multi-vendor IT Systems

As IT systems grow bigger and complex, they are comprised of many resources supplied by various vendors. Also, the Internet accelerates inter-enterprise business transactions and IT systems are connected each other. Consequently enterprise application systems are becoming a kind of large business process across multiple vendors. This transformation will also bring new type of complexity and difficulties to enterprise IT system management. Having awareness of these issues, IBM and Fujitsu have been collaborating on standardization effort for various areas of autonomic computing technologies. Autonomic computing and open standard interface are an effective approach to deal with these challenges. The initial areas of collaboration are common event format and interface for action to manage IT resources. hi this presentation, we show how an autonomic manager can solve these issues with using an open standard, WSDM (Web Service Distributed Management). We demonstrate the autonomic manager that behaves based on defined policy, continuously monitors systems, handles events and takes actions through WSDM interface in Multi-vendor IT Systems.