Efficient memory management in VOD disk array servers usingPer-Storage-Device buffering

We present a buffering technique that reduces video-on-demand server memory requirements in more than one order of magnitude. This technique, Per-Storage-Device Buffering (PSDB), is based on the allocation of a fixed number of buffers per storage device, as opposed to existing solutions based on per-stream buffering allocation. The combination of this technique with disk array servers is studied in detail, as well as the influence of Variable Bit Streams. We also present an interleaved data placement strategy, Constant Time Length Declustering, that results in optimal performance in the service of VBR streams. PSDB is evaluated by extensive simulation of a disk array server model that incorporates a simulation based admission test.This research was supported in part by the National R&D Program of Spain, Project Number TIC97-0438.Publicad

Ethernet - a survey on its fields of application

During the last decades, Ethernet progressively became the most widely used local area networking (LAN) technology. Apart from LAN installations, Ethernet became also attractive for many other fields of application, ranging from industry to avionics, telecommunication, and multimedia. The expanded application of this technology is mainly due to its significant assets like reduced cost, backward-compatibility, flexibility, and expandability. However, this new trend raises some problems concerning the services of the protocol and the requirements for each application. Therefore, specific adaptations prove essential to integrate this communication technology in each field of application. Our primary objective is to show how Ethernet has been enhanced to comply with the specific requirements of several application fields, particularly in transport, embedded and multimedia contexts. The paper first describes the common Ethernet LAN technology and highlights its main features. It reviews the most important specific Ethernet versions with respect to each application field’s requirements. Finally, we compare these different fields of application and we particularly focus on the fundamental concepts and the quality of service capabilities of each proposal

A Practical Approach to Protect IoT Devices against Attacks and Compile Security Incident Datasets

open access articleThe Internet of Things (IoT) introduced the opportunity of remotely manipulating home appliances (such as heating systems, ovens, blinds, etc.) using computers and mobile devices. This idea fascinated people and originated a boom of IoT devices together with an increasing demand that was difficult to support. Many manufacturers quickly created hundreds of devices implementing functionalities but neglected some critical issues pertaining to device security. This oversight gave rise to the current situation where thousands of devices remain unpatched having many security issues that manufacturers cannot address after the devices have been produced and deployed. This article presents our novel research protecting IOT devices using Berkeley Packet Filters (BPFs) and evaluates our findings with the aid of our Filter.tlk tool, which is able to facilitate the development of BPF expressions that can be executed by GNU/Linux systems with a low impact on network packet throughput

Study, Analysis and Modeling of IP Multimedia systems on next generation networks providing mobile and fixed multimedia services

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UOGÓLNIONY MODEL PROCESU OCHRONY INFORMACJI W SIECIACH DYSTRYBUCJI TREŚCI AUDIOWIZUALNYCH

The most important indicators of the effectiveness of content protection systems are indicators of the achieved security level, i.e. functional properties of security. These indicators are: confidentiality, integrity, availability. Each of the indicators of the functional properties of content security is distributed according to the methods of ensuring and the degree of its achievement. A significant drawback of such indicators is that they are qualitative. This significantly narrows the scope of their use and makes it impossible to use them in mathematical expressions for optimizing the parameters of protection means, obtaining quantitative estimates of the performance quality of the protection system or its components, etc. The work offers a number of quantitative indicators, which, depending on the purpose, can be probabilistic and temporal. Calculation of such indicators makes it possible to assess the degree of ensuring the functional properties of information security or the possible degree of ensuring the functional properties of protected information.Najważniejszymi wskaźnikami skuteczności systemów ochrony treści są wskaźniki osiągniętego poziomu bezpieczeństwa – właściwości funkcjonalne zabezpieczeń. Takimi wskaźnikami są: poufność, integralność, dostępność. Każdy ze wskaźników właściwości funkcjonalnych bezpieczeństwa treści jest podzielony ze względu na metody zapewnienia i stopień ich osiągnięcia. Istotną wadą takich wskaźników jest to, że są one jakościowe. Zawęża to znacznie zakres ich stosowania i uniemożliwia wykorzystanie ich w wyrażeniach matematycznych do optymalizacji parametrów środków ochrony, uzyskania ilościowych ocen jakości działania systemu ochrony lub jego elementów itp. W pracy zaproponowano szereg wskaźników ilościowych, które w zależności od celu mogą mieć charakter probabilistyczny i czasowy. Obliczenie takich wskaźników pozwala ocenić stopień zapewnienia właściwości funkcjonalnych bezpieczeństwa informacji lub możliwy stopień zapewnienia właściwości użytkowych chronionych informacji

A Comprehensive Survey of Voice over IP Security Research

We present a comprehensive survey of Voice over IP security academic research, using a set of 245 publications forming a closed cross-citation set. We classify these papers according to an extended version of the VoIP Security Alliance (VoIPSA) Threat Taxonomy. Our goal is to provide a roadmap for researchers seeking to understand existing capabilities and to identify gaps in addressing the numerous threats and vulnerabilities present in VoIP systems. We discuss the implications of our findings with respect to vulnerabilities reported in a variety of VoIP products. We identify two specific problem areas (denial of service, and service abuse) as requiring significant more attention from the research community. We also find that the overwhelming majority of the surveyed work takes a black box view of VoIP systems that avoids examining their internal structure and implementation. Such an approach may miss the mark in terms of addressing the main sources of vulnerabilities, i.e., implementation bugs and misconfigurations. Finally, we argue for further work on understanding cross-protocol and cross-mechanism vulnerabilities (emergent properties), which are the byproduct of a highly complex system-of-systems and an indication of the issues in future large-scale systems