Monitoring and Management of Peer-to-Peer Systems
Supervisor(s) and Committee member(s): Prof. Dr.-Ing. Ralf Steinmetz (Supervisor), Prof. Carmen Guerrero Lopez, Ph.D. (Referee)
The peer-to-peer paradigm has had large success in content distribution and multimedia communication applications on the Internet. In a peer-to-peer network, the participating nodes create an infrastructure to provide a desired functionality and offer their resources to host an application in a distributed manner.
Besides the functional requirements of an application, the non-functional requirements to achieve a high service quality are also an important part of successful peer-to-peer networks and a major challenge is to meet these requirements in networks with unreliable nodes. In contrast to traditional centralized approaches where the quality can be measured and controlled, in a distributed environment it is challenging both to capture the status and performance of the whole distributed system in one point of time and to control its general behavior. In this dissertation, we focus on the monitoring and management of peer-to-peer systems.
We systematically engineer SkyEye.KOM, a fully decentralized monitoring mechanism that provides both a precise status snapshot of the peer-to-peer system and enables queries for peer capacities, such as bandwidth or storage capacities, in a large-scale peer-to-peer system. It considers individual load limits of the peers and ensures that no peer is overloaded. The core tree topology of SkyEye.KOM is established and maintained solely with protocol-relevant messages. It is based on local peer identifier calculations and using the underlying peer-to-peer overlay. As a second step, we focus on the management of peer-to-peer systems and introduce P3R3O.KOM and SkyNet.KOM, two solutions to manage both the reservation of available capacities in the peer-to-peer system and the system behavior in a fully decentralized and efficient manner. P3R3O.KOM is a peer-to-peer protocol for reliable long-term resource reservation that overcomes the limitations of traditional peer-to-peer services, which typically are host only by single peers and cease once the service providing peer fails. Resource reservations are fulfilled with adjustable guarantees (even 100%) in the presence of strong churn through the automated and fully decentralized management of the resource provision redundancy. With SkyNet.KOM, we present a fully decentralized approach for automated management of peer-to-peer systems following the principles of autonomic computing. It allows the user or system provider to set service quality goals for the peer-to-peer system, which are automatically verified by the monitoring solution SkyEye.KOM and analyzed, aligned and enforced by the other components of SkyNet.KOM. Preset quality goals for the peer-to-peer system are reached and held through automated systematic re-configuration of the individual components of the peer-to-peer system. At the end, we present LifeSocial.KOM, a peer-to-peer-based platform for online social networks that incorporates the proposed monitoring mechanism to show the feasibility and application scope of the monitoring and management solutions.
The impact of the thesis is to be seen in extending the applicability of the peer-to-peer paradigm to quality critical applications and scenarios. Through the monitoring approach, a system provider is able to observe and judge the quality of the peer-to-peer system. Regarding the function of capacity-based peer search, the capacities in a peer-to-peer system may be addressed and used to a full extent, allowing for the creation of applications with rich functionality using a wide set of capacities. Through the proposed management mechanisms, these capacities can also be used reliably in the presence of churn to host services and to establish the peer-to-peer paradigm as a serious and reliable alternative to traditional IT architectures. Additionally, through the automated quality control proposed with SkyNet.KOM, quality-controlled peer-to-peer applications may be created and operated, despite being hosted on a large-scale network of unreliable nodes. Lastly, peer-to-peer-based online social networks show the potential to become the next large application area for the peer-to-peer paradigm. LifeSocial.KOM is one of the first in this category and presents a viable approach for quality-aware peer-to-peer applications that satisfies the needs of both users and system providers.
Multimedia Communications Lab (KOM), TU Darmstadt, Germany
The Multimedia Communications Lab (KOM) is led by Prof. Dr.-Ing. Ralf Steinmetz and strives to work towards the vision of seamless communications, whereby people worldwide independent of their location as well as the used end-systems and devices are able to communicate and work with each other efficiently and effectively.
To reach this goal KOM works on mechanisms for the realization of QoS, security, adaptivity and context-awareness in systems and networks. We address in particular networks (e.g. p2p and mobile networks), communication services (e.g. IP based communication services), IT architectures (e.g. service oriented architectures), and media contents (media for information and knowledge sources, and community applications).
Application areas for the research at KOM are, for example, E-Business, E-Finance, and E-Learning.