Efficient algorithm for mobile multicast using anycast group

The authors present a novel and efficient multicast algorithm that aims to reduce delay and communication cost for the registration between mobile nodes and mobility agents and solicitation for foreign agent services based on the mobile IP. The protocol applies anycast group technology to support multicast transmissions for both mobile nodes and home/foreign agents. Mobile hosts use anycast tunnelling to connect to the nearest available home/foreign agent where an agent is able to forward the multicast messages by selecting an anycast route to a multicast router so as to reduce the end-to-end delay. The performance analysis and experiments demonstrated that the proposed algorithm is able to enhance the performance over existing remote subscription and bidirectional tunnelling approaches regardless of the locations of mobile nodes/hosts<br /

Mobile object location discovery in unpredictable environments

Emerging mobile and ubiquitous computing environments present hard challenges to software engineering. The use of mobile code has been suggested as a natural fit for simplifing software development for these environments. However, the task of discovering mobile code location becomes a problem in unpredictable environments when using existing strategies, designed with fixed and relatively stable networks in mind. This paper introduces AMOS, a mobile code platform augmented with a structured overlay network. We demonstrate how the location discovery strategy of AMOS has better reliability and scalability properties than existing approaches, with minimal communication overhead. Finally, we demonstrate how AMOS can provide autonomous distribution of effort fairly throughout a network using probabilistic methods that requires no global knowledge of host capabilities

An adaptive communication model for mobile agents in highly dynamic networks based on forming flexible regions via swarming behabiour

Im letzten Jahrzehnt gilt die mobile Agententechnologie als eines der wichtigsten Forschungsgebiete der Informatik. Mobile Agenten sind Software, die Aufträge im Namen ihrer Besitzer erfüllen können (ZK02). Mobile Agenten können selbstbestimmend von Server zu Server migrieren, sie können ihren Arbeitsstand speichern und dann ihre Arbeit am neuen Aufenthaltsort fortsetzen. Ihre wichtigsten Merkmale sind: autonom, reaktiv, opportunistisch und zielgerichtet. Diese genannten Merkmale sind für verteilte Anwendungen geeignet, z. B: Ressourcenverteilung (TYI99), Netzwerkmanagement (MT99), E-Commerce (BGP05), Fernüberwachung CMCV02), Gesundheitssysteme (Mor06), um nur einige zu nennen. Es ist die Mobilität der Agenten, die mobile Agenten zu einer guten Computing Technologie macht (Pau02). Kommunikation ist wesentlich in verteilten Systemen, und dies gilt auch für mobile Agentensysteme (LHL02). Neben den eher technischen Aspekten mobiler Agententechnologien, wie Migration (Bra03) und Kontrollmechanismen (Bau00), wurde die Kommunikation zwischen den Agenten als eine der wichtigsten Komponenten in der mobilen Agententechnologie identifiziert (FLP98). Es ist diskutiert worden, ob Agentenkommunikation ausschließlich lokal sein sollte, angesichts der Tatsache, dass mobile Agenten erfunden wurden, weil man die Verarbeitung zu den Daten tragen möchte, anstatt umgekehrt (SS97). Allerdings hat es sich gezeigt, dass es in vielen Fällen lohnt, wenn die mobilen Agenten kommunizieren anstatt migrieren (BHR+97),(FLP98),(ea02). Kommunikation hilft mobilen Agenten, eine bessere Leistung zu erreichen (Erf04). Kommunikation ist daher aus unserer Sicht die Basis mobiler Agentensysteme. An der Friedrich-Schiller-Universität Jena ist das interdisziplinäre Projekt SpeedUp seit April 2009 durchgeführt worden (FSU11). Das Projekt entwickelt ein Unterstützungssystem für Rettungs- und Einsatzkräfte bei einem Massenanfall von Verletzten (MANV). Im Projekt ist das Konzept mobiler Agenten als eine der Basistechnologien ausgesucht worden. Die hohe Netzwerkdynamik stellt neue Herausforderungen für mobile Agentensysteme dar, die in MANV Rettungsszenarien arbeiten. Es wird erwartet, dass die Kommunikation sich an die dynamische Umgebung zur Ausführungszeit anpassen kann. Dazu fehlen heute tragfähige Konzepte. In dieser Arbeit wird daher ein Ansatz zur adaptiven Kommunikation mobiler Agenten in hochdynamischen Netzwerken des SpeedUp-Typs vorgestellt. Nach unserer Beurteilung sollte die Kommunikation zwischen den mobilen Agenten nicht nur Interoperabilität und Standortunabhängigkeit, sondern auch Anpassungsfähigkeit aufweisen. Wir schlagen ein Kommunikationsmodell vor, das sich auf den koordinierenden Aspekt und das Zusammenspiel der Agenten konzentriert, sowie die Zuverlässigkeit und die Fehlertoleranz unterstützt. Um die Netzwerkdynamik zu managen, planen wir einen selbstorganisierten Mechanismus zu verwenden, der sich ”honey bee” inspiriertes Verfahren nennt. Wir werden dazu eine Software für ein adaptives Kommunikationsmodell mobiler Agenten, basierend auf das mobile Agentensystem Ellipsis gestalten, implementieren, und evaluieren.In the last decade, mobile agent technology has been considered as one of the most active research fields in computer science. Mobile agents are software agents which run on behalf of their owner to fulfil jobs that have been ordered (ZK02). They have the ability to migrate from location to location in the network, they can temporarily save their work state at the time of migrating and then restore their tasks when arriving at the new location. Their outstanding characteristics are to be autonomous, reactive, opportunistic, and goal-oriented. Those characteristics are suitable for distributed applications, such as resource allocation (TYI99), network management (MT99), remote supervision (CMCV02), e-commerce (BGP05), health care systems (Mor06), to name but a few. It is the mobility of mobile agents that makes them to be a powerful computing technique, especially for pervasive computing (Pau02). Communication is an essential component of distributed systems and this is no exception for multiagent systems (LHL02). Besides technical aspects of mobile agent technology, such as migrations (Bra03) and control mechanisms (Bau00), communication between mobile agents has been identified as an important issue in mobile agent technology (FLP98). It has been argued whether agent communication should be remote or restricted to local, considering that the main reason for the birth of mobile agents was to move computation to the data instead of moving the data to the computation. Therefore, remote communication could be avoided completely (SS97). However, it has been shown that in many cases mobile agent systems can benefit from performing communication instead of sending agents to remote platforms (BHR+97),(FLP98),(ea02). The communication between agents helps to increase the chance that an agent attains its objectives (Erf04). Communication is one of the bases of multi-agent systems; it is difficult, if not impossible for a group of agents to solve tasks without communication (Hel03). At Friedrich Schiller University Jena, an interdisciplinary project, named SpeedUp, for the support of handling mass casualty incidents (MCI) has been in development since April 2009 (FSU11). In the project the mobile agent concept has been selected as one of the main technologies on the communication infrastructure level. The dynamic nature of MCI networks poses new challenges to mobile systems working in a rescue scenario. For mobile agent systems working in highly dynamic networks, communication between mobile agents is expected to adapt easily to environmental stimuli which occur at execution time. Much research has been done into the design of an appropriate, highly flexible model for mobile agent communication in dynamic networks. However, to the best of our knowledge none of the suggested solutions has been able to achieve the necessary performance and quality attributes to count as a practical solution. In most cases, these existing approaches seem to neglect the inherent dynamics of modern networks. In this dissertation, we present our approach for an adaptive communication model for mobile agent systems in highly dynamic networks of the SpeedUp type. In our opinion, communication in mobile agent systems should deal not only with interoperability and location-transparency, but also with adaptability. To achieve industrial strength, we propose a model for agent communication that focuses on the cooperation aspect of agent interaction and supports reliability and fault tolerance as the key qualities, while keeping up an acceptable overall performance at the same time. For the management of highly dynamic communication domains we use a self-organizing mechanism, a so-called honey bee inspired algorithm. In order to ensure message delivery, we propose a resilient mechanism for the management of a mobile agent’s location. Based on this thesis, we will design, implement and evaluate a software prototype for an adaptive model for mobile agent communication based on the Ellipsis mobile agent system

Elastic Highly Available Cloud Computing

High availability and elasticity are two the cloud computing services technical features. Elasticity is a key feature of cloud computing where provisioning of resources is closely tied to the runtime demand. High availability assure that cloud applications are resilient to failures. Existing cloud solutions focus on providing both features at the level of the virtual resource through virtual machines by managing their restart, addition, and removal as needed. These existing solutions map applications to a specific design, which is not suitable for many applications especially virtualized telecommunication applications that are required to meet carrier grade standards. Carrier grade applications typically rely on the underlying platform to manage their availability by monitoring heartbeats, executing recoveries, and attempting repairs to bring the system back to normal. Migrating such applications to the cloud can be particularly challenging, especially if the elasticity policies target the application only, without considering the underlying platform contributing to its high availability (HA). In this thesis, a Network Function Virtualization (NFV) framework is introduced; the challenges and requirements of its use in mobile networks are discussed. In particular, an architecture for NFV framework entities in the virtual environment is proposed. In order to reduce signaling traffic congestion and achieve better performance, a criterion to bundle multiple functions of virtualized evolved packet-core in a single physical device or a group of adjacent devices is proposed. The analysis shows that the proposed grouping can reduce the network control traffic by 70 percent. Moreover, a comprehensive framework for the elasticity of highly available applications that considers the elastic deployment of the platform and the HA placement of the application’s components is proposed. The approach is applied to an internet protocol multimedia subsystem (IMS) application and demonstrate how, within a matter of seconds, the IMS application can be scaled up while maintaining its HA status

Using mobility and exception handling to achieve mobile agents that survive server crash failures

Mobile agent technology, when designed and used effectively, can minimize bandwidth consumption and autonomously provide a snapshot of the current context of a distributed system. Protecting mobile agents from server crashes is a challenging issue, since developers normally have no control over remote servers. Server crash failures can leave replicas, instable storage, unavailable for an unknown time period. Furthermore, few systems have considered the need for using a fault tolerant protocol among a group of collaborating mobile agents. This thesis uses exception handling to protect mobile agents from server crash failures. An exception model is proposed for mobile agents and two exception handler designs are investigated. The first exists at the server that created the mobile agent and uses a timeout mechanism. The second, the mobile shadow scheme, migrates with the mobile agent and operates at the previous server visited by the mobile agent. A case study application has been developed to compare the performance of the two exception handler designs. Performance results demonstrate that although the second design is slower it offers the smaller trip time when handling a server crash. Furthermore, no modification of the server environment is necessary. This thesis shows that the mobile shadow exception handling scheme reduces complexity for a group of mobile agents to survive server crashes. The scheme deploys a replica that monitors the server occupied by the master, at each stage of the itinerary. The replica exists at the previous server visited in the itinerary. Consequently, each group member is a single fault tolerant entity with respect to server crash failures. Other schemes introduce greater complexity and performance overheads since, for each stage of the itinerary, a group of replicas is sent to servers that offer an equivalent service. In addition, future research is established for fault tolerance in groups of collaborating mobile agents