Catálogo de publicaciones - libros

Recent work on self-stabilizing routing in publish/subscribe systems showed that it is feasible to automate reconfigurations in case of faults by enabling the system to recover from arbitrary transient faults. In this paper, we discuss how to incorporate planned reconfigurations of the broker topology into self-stabilizing publish/subscribe systems without service interruption. We present an algorithm that uses a coloring mechanism to enable the system to be automatically switched from one system configuration to another. The colors thereby synchronize the broker overlay and the publish/subscribe routing layer.

The standard definition of autonomics is that of self-governance, including such properties as self-configuring, self-healing and self-optimizing. To really enable self-anything, however, we must first deliver another ‘self-’ property – self-knowledge. We define self-knowledge as information about a system enabling it to reason on its own capabilities and actions. This knowledge can come in many forms but we propose that there are essentially two key elements: knowledge of the individual parts of the system, and knowledge about the rules that determine the interaction of these system components. This paper presents a model describing self-knowledge, with policy for defining rules and profiles to express the individual entities knowledge.

As Structured Peer-to-Peer (P2P) Networks become popular, there is an emerging need to monitor continuously the huge number of participants in a robust and scalable manner. To this end, aggregation has emerged as a basis for the self-management of these networks. However, the structured P2P networks lack today of efficient mechanisms for the decentralized computation of these aggregates. In this paper, we propose a hierarchical theoretic model based on Cayley Graphs, which overcomes the requisite to accommodate growth without impacting the efficiency of distributed applications. Also, the paper presents an aggregation protocol that fuses the fault-resilience of gossip algorithms with the scalability of trees. In particular, simulation results show that this algorithm is capable to cope with the distributed and unreliable nature of P2P networks.

When different wireless networks come in close proximity there is often a need for them to logically combine, or . We focus on a known research problem particularly in Ambient Networks (ANs), where hetero-geneous Distributed Hash Tables (DHTs) contained in these wireless networks need to merge or divide as a result of these dynamic (de)composition processes, respectively. We present two novel DHT (de)composition models for ANs, known as and , that are designed to handle (de)composition of DHTs in different AN network environments, with minimal disturbance to existing member nodes.

According to ITIL, a CMDB (Configuration Management Database), containing a logical model of the IT infrastructure, forms the basis for effective and efficient IT Service Management. However, a common understanding of what constitutes a CMDB has not yet been established. By contrast, concepts for building and using MIBs (Management Information Base) – also aimed at providing logical models of the IT infrastructure – have long since been established in the area of systems management.

This paper presents an overview of the CMDB and MIB concepts, discusses how they relate to each other and compares them based on the main purposes of a CMDB. It discusses whether modeling approaches used for MIBs can be reused for CMDBs. To this end, a criteria catalog based on core CMDB concepts and basic information requirements of ITIL’s Service Management processes are derived, and the challenges of implementing a CMDB reusing concepts of common management models are discussed. Concluding, basic approaches towards integrating CMDBs and MIBs are presented.