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The focus of this thesis is continuous real-time monitoring, which is essential for the realization of adaptive management systems in large-scale dynamic environments. Real-time monitoring provides the necessary input to the decision-making process of network management. We have developed, implemented, and evaluated a design for real-time continuous monitoring of global metrics with performance objectives,...
Efficient Web services (WS) based network monitoring of managed devices is a difficult task due to the relatively big overhead WS impose. In the past we proposed mechanisms to perform distributed monitoring efficiently, minimizing the relevant overhead. Standardization of WS operations is also important in order to achieve interoperability. The WS Resource Framework (WSRF) tries to standardize the...
Today's backbone communication networks serve a wide range of services with different availability requirements. Each customer has a contract, denoted a Service Level Agreement (SLA) which specifies the availability requirement over the contract period. In the literature, different provisioning strategies to establish connection arrangements capable of meeting a statistical asymptotic availability...
In recent years, IT service management (ITSM) has become one of the most researched areas of IT. Incident and problem management are two of the service operation processes in the IT infrastructure library (ITIL). These two processes aim to recognize, log, isolate and correct errors which occur in the environment and disrupt the delivery of services. Incident management and problem management form...
During the last decade several network management solutions have been proposed or extended to cope with the growing complexity of networks, systems and services. Architectures, protocols, and information models have been proposed as a way to better respond to the new and different demands of global networks. However this offer also leads to a growing complexity of management solutions and to an increase...
Cryptographic techniques are at the center of security solutions for wireless ad hoc networks. Public key infrastructures (PKIs) are essential for their efficient operation. However, the fully distributed organization of these networks makes a challenge to design PKIs. Moreover, changes in network paradigms and the increasing dependency on technology require more dependable, survivable and scalable...
Network security administrators cannot always accurately tell which end-to-end accesses are permitted within their network, and which ones are not. The problem is that every access is determined by the configurations of multiple, separately administered, components. As configurations evolve, a small change in one configuration file can have widespread impact on the end-to-end accesses. Short of exhaustive...
In this paper we propose an IP traceback mechanism based on deterministic packet marking and logging, using protected nodes set to reduce logged data amount. The proposed scheme exploits the fact that the number of nodes that may be under attack is usually limited to a small fraction of total nodes in the Internet, greatly reducing storage requirements by logging only the traffic destined to this...
Network measurement provides vital information on the health of managed networks. The collection of network information can be used for several reasons (e.g., accounting or security) depending on the purpose the collected data will be used for. At the University of Twente (UT), an automatic decision process for hybrid networks that relies on collected network information has been investigated. This...
Industrial process control IP networks support communications between process control applications and devices. Communication faults in any stage of these control networks can cause delays or even shutdown of the entire manufacturing process. The current process of detecting and diagnosing communication faults is mostly manual, cumbersome, and inefficient. Detecting early symptoms of potential problems...
Component level performance thresholds are widely used as a basic means for performance management. As the complexity of managed systems increases, manual threshold maintenance becomes a difficult task. This may result from a) a large number of system components and their operational metrics, b) dynamically changing workloads, and c) complex dependencies between system components. To alleviate this...
In spite of the large effort behind the development of the WBEM and CIM standards for the management of distributed systems, there has been very little work addressing security in those standards. In this paper we present a role-based access control (RBAC) policy language to render fine-grained access control policies for WBEM and CIM. The language is an extension of CIM-SPL, a preliminary DMTF policy...
The motivation of the presented thesis emanated from the need for unrestricted wireless communication in a scalable and predictable manner. This need is accentuated by the increasing users' demand for spontaneous communication. The objective is to propose a management framework able to leverage the potential of wireless ad hoc networks as an alternative communication method allowing them to coexist...
We present a policy conflict analysis process that makes use of pre-defined semantic models of an application to perform effective and efficient conflict analysis. The process is effective as it can be used to analyse for policy conflicts that may occur in different applications due to the separation of application specific information and constraints from the algorithms to semantic models, such as...
With the emergence of new applications and requirements it became necessary to create new monitoring and reactive configuration mechanisms to try to meet the SLAs (service level agreements). In WDM (wavelength division multiplexing) optical networks, one way of trying to fulfill these agreements is by using pre-established protection paths. However, despite guaranteeing that traffic will be rapidly...
PhoneFactortrade is a token-less two-factor authentication service for user remote logons. This allows users of an organization to be authenticated through an automated phone call to the user's phone before access is allowed. In this paper, we present the service management architecture of PhoneFactor that depends on both the Internet and the public switched telephone network (PSTN), and we identify...
The decentralization of corporate policy administration aiming to maintain the unified management of user permissions is a hard task. The heterogeneity and complexity of corporate environments burdens the security administrator with writing equally complex policies. This paper proposes an architecture based on Web Services, policy provisioning, and authorization certificates, to build up a loosely...
Massively online virtual environments (MOVEs) have been gaining popularity for several years. Today, these complex networked applications are serving thousands of clients simultaneously. However, these MOVEs are typically hosted on specialized server clusters and rely on internal knowledge of the services to optimize the load balancing. This makes running MOVEs an expensive undertaking as it cannot...
The configuration and runtime management of distributed systems is often complex due to the presence of a large number of configuration options and dependencies between interacting sub-systems. Inexperienced users usually choose default configurations because they are not aware of the possible configurations and/or their effect on the systems' operation. In doing so, they are unable to take advantage...
The main goal of change management is to ensure that standardized methods and procedures are used for the efficient and prompt handling of changes in IT systems, in order to minimize change-related incidents and service-delivery disruption. To meet this goal, it is of paramount importance reusing the experience acquired from previous changes in the design of subsequent ones. Two distinct approaches...
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