1,721,122 research outputs found
A Novel Approach to Marshalling
No full text{Assembling a collection of typed data into a form suitable for being sent across a network (marshalling) is one of the basic functionalities of any distributed system. This job is typically done by means of pieces of code (stubs) tailored to each type and linked to every process that needs them. This paper presents a novel approach where it is a single module, called the Marshalling Machine (MM), that performs marshalling by using a description of the data structure to be transferred. Such a description is in fact a program written in a simple assembly-like language specialized for marshalling, and MM is an interpreter for this language. The design and implementation of both MM and its language are discussed in detail. The performance of a prototype is analysed, and it is shown that the potential performance loss intrinsic to this interpreted approach is unlikely to be a practical issue. The reason is because, essentially, the cost of decoding instructions of the MM language is negligible compared to the fixed costs of the entire message-passing machinery. Motivations for this work are the potential advantages of an MM-based run-time system over a traditional approach based on compiled stubs. These advantages are discussed extensively, and include greater flexibility, simpler generation of distributed programs, a smaller number of memory-to-memory copies in the message-passing machinery, and elegant accommodation of services whose interface is discovered at run-time. {\copyright} 1997 by John Wiley \& Sons, Ltd.
Group-based multicast and dynamic membership in wireless networks with incomplete spatial coverage
No full text{In this paper we examine the problem of group-based multicast communication in the context of mobile computing with wireless communication technology. We propose a protocol in which group members may be mobile computers and such that the group membership may change dynamically. Multicasts are delivered in the same order at all group members (totally-ordered multicast). Mobile computers are resource-poor devices that communicate with a wired network through a number of spatially limited cells defining wireless links. The spatial coverage provided by wireless links may be either complete or incomplete, which makes the overall system model both general and realistic. The proposed protocol is simple and does not require any hand-off in the wired network upon movements of group members. Moreover, there is no part of the protocol requiring that group members do not move during its execution. This feature leads to mobility assumptions that are practical because they involve only the global movement of group members, e.g., assumptions of the form ” a group member does not move very fast all the time”.
Robustness analysis of DNS paths and web access paths in public administration websites
Full text linkAttacks at the naming or the routing infrastructure of the Internet have long become a reality and one single such attack has the potential of affecting access to Internet-facing services in many organizations. An important question to address is assessing the potential impact of attacks of this sort on the web infrastructure of an entire nation. In this work we examine the dependence of a large set of public administration websites on DNS entities and autonomous systems of four different countries: Italy, Germany, UK and US. We collected the dependencies of those websites from DNS zones, nameservers, networks, autonomous systems, and assessed the potential global impact of localized attacks on those entities. We also analyzed the prevalence of such defensive technologies as BGP Route Origin Authorization, DNSSEC and HTTPS Strict Transport Security. Our analysis highlights the structural interdependencies within the web infrastructures of public interest and illustrates the corresponding open problems, issues whose relevance can only grow
Understanding Server Authentication in WPA3 Enterprise
Full text linkIn December 2019, the Wi-Fi Alliance published version 2 of WPA3, the new certification program for Wi-Fi devices that updates WPA2. This new version of WPA3 addresses, amongst other things, one of the crucial weaknesses of WPA2: in many practical deployments of enterprise Wi-Fi networks—i.e., networks in which users have personalized credentials—a device may easily be attacked by fraudulent access points claiming to have the name of the targeted network (evil twins). In this work, we present the mechanisms that WPA3 version 2 has introduced for mitigating these risks, which have become more and more relevant in recent years. We discuss the defensive power and potential impact of the various options available. Understanding the resulting scenario is important because WPA3 will determine the behavior of such a fundamental and widespread technology as enterprise Wi-Fi for many years, yet WPA3 enterprise networks may still be configured in a way that could not provide much better defensive power than WPA2
Bibliometric Evaluation of Researchers in the Internet Age
No full textResearch evaluation, which is an increasingly pressing issue, invariably relies on citation counts. In this contribution we highlight two concerns that the research community needs to pay attention to. One, in the world of search engine facilitated research, factors such as ease of web discovery, ease of access, and content relevance rather than quality influence what gets read and cited. Two, research evaluation based on citation counts works against many types of high-quality works. We will also elaborate on the implications of these points by examining a recent nation-wide evaluation of researchers performed in Italy. We focus on our discipline (computer science), but we believe that our observations have relevance for a broad audience
Citation Counts and Evaluation of Researchers in the Internet Age
No full textBibliometric measures derived from citation counts are increasingly being used as a research evaluation tool. Their strengths and weaknesses have been widely analyzed in the literature and are often subject of vigorous debate. We believe there are a few fundamental issues related to the impact of the web that are not taken into account with the importance they deserve. We focus on evaluation of researchers, but several of our arguments may be applied also to evaluation of research institutions as well as of journals and conferences
- …
