Verifiable Network-Performance Measurements

In the current Internet, there is no clean way for affected parties to react to poor forwarding performance: when a domain violates its Service Level Agreement (SLA) with a contractual partner, the partner must resort to ad-hoc probing-based monitoring to determine the existence and extent of the violation. Instead, we propose a new, systematic approach to the problem of forwarding-performance verification. Our mechanism relies on voluntary reporting, allowing each domain to disclose its loss and delay performance to its neighbors; it does not disclose any information regarding the participating domains' topology or routing policies beyond what is already publicly available. Most importantly, it enables verifiable performance measurements, i.e., domains cannot abuse it to significantly exaggerate their performance. Finally, our mechanism is tunable, allowing each participating domain to determine how many resources to devote to it independently (i.e., without any inter-domain coordination), exposing a controllable trade-off between performance-verification quality and resource consumption. Our mechanism comes at the cost of deploying modest functionality at the participating domains' border routers; we show that it requires reasonable processing and memory resources within modern network capabilities.Comment: 14 page

Dealing with the need of Greek ports expansion: a public-private partnership opportunity?

Greece, located at the eastern portion of the Mediterranean Sea (Med) and a country with an enormous number of islands, is a shipping superpower. The Med is amongst the world’s busiest waterways. It provides access to the Black Sea and quite often it is characterized as the most important element of the transport chain between Asia and Europe. The Greek Prime-Minister himself has openly declared his strategic vision to transform the country into a major hub for Europe\u27s commerce; numbers of port-visits in the country under discussion are extremely high and expectations are that with the upcoming recovery of the Greek economy they will further increase. However, the current infrastructures -especially those of Piraeus and Thessaloniki (the largest and busiest ports of the Hellenic Republic)- are clearly in need of expansion. This paper briefly examines the framework of Public-Private Partnerships (PPP) and suggests that the specific methodology can provide a solution to overcome the need of financing for the various urgently needed projects that will allow the introduction of new and improved services towards various types of ships. The obvious conclusion is that with the Greek economy still in recession, the necessary framework that will allow the commencing of the technical works, such as the expansion of berths and storage facilities and the interconnections with highways and rail-lines, can be found only through partnerships of the government controlled port-authorities and large in size constructing companies of the private sector. These partnerships should be considered as a win-win situation for all parties involved. They provide an ideal opportunity for expanding infrastructures and/or services towards shipping without adding more to the already enormous government-guaranteed debt

2 P2P or Not 2 P2P?

In the hope of stimulating discussion, we present a heuristic decision tree that designers can use to judge the likely suitability of a P2P architecture for their applications. It is based on the characteristics of a wide range of P2P systems from the literature, both proposed and deployed.Comment: 6 pages, 1 figur