A RTT-based Partitioning Algorithm for a Multi-rate Reliable Multicast Protocol

Various Internet applications involve multiple parties and usually adopt a one-to-many communication paradigm (multicast). The presence of multiple re ceivers in a multicast session rises the problem of inte¡ r-receiver fairness. Transmitting with a rate which matches the slowest receiver will limit the throughput of other receivers and thus their satisfaction. A multi-rate mechanism where the receivers are distributed into subgroups with similar capacities, can improve the inter-receiver fairness for multicast sessions. In this paper, we deal with the problem of receivers partitioning and propose a simple algorithm based on the receivers RTT variations where an explicit estimation of the receivers capacities is avoided. Our partitioning algorithm, although simple, performs an on-the-fly partitioning depending on the receivers' feedback. We show that our partitioning algorithm approximates and in many cases, achieves the optimal solution with a minimum computation effort

A RTT-based Partitioning Algorithm for a Multi-rate Reliable Multicast Protocol

Various Internet applications involve multiple parties and usually adopt a one-to-many communication paradigm (multicast). The presence of multiple receivers in a multicast session rises the problem of inter-receiver fairness. Transmitting with a rate which matches the slowest receiver will limit the throughput of other receivers and thus their satisfaction. A multi-rate mechanism where the receivers are distributed into subgroups with similar capacities, can improve the inter-receiver fairness for multicast sessions. In this report, we deal with the problem of receivers partitioning and propose a simple algorithm based on the receivers RTT variations where an explicit estimation of the receivers capacities is avoided. Our partitionin- g algorithm, although simple, performs an on-the-fly partitioning depending on the receivers' feedback. We show that our partitioning algorithm approximates and in many cases, achieves the optimal solution with a minimum computation effort.Une grande variété d'applications impliquent la participation de plusieurs entités, ainsi un paradigme de communication one-to-many (multicast) y est le plus adapté. La présence de plusieurs récepteurs dans une session de multicast soulève le problème de l'équité inter-récepteurs. L'émission avec le débit du récepteur le plus lent limita sans doute la satisfaction des autres récepteurs; Un mécanisme multi-débit où les récepteurs sont partitionnés sur des sous-groupes de capacités similaires, pourrait améliorer considérablement l'équité inter-récepteur. dans ce rapport, nous traitons le problème du partitionnement des récepteurs et proposons un algorithme simple basé sur les variations du RTT des différents récepteurs. une estimation explicite des capacités des récepteurs est ainsi évitée. Notre algorithme de partitionnement fait un partitionnement à-la-volée en fonction des messages de contrôle provenant des récepteurs. on montre que l'algorithme proposé approche e dans plusieurs cas atteint la solution optimale avec une complexité minimal

Dealing with Heterogeneity in a Fully Reliable Multicast Protocol

Many of the proposed multicast congestion avoidance algorithms are single-rate where heterogeneity is accommodated by adjusting the transmission rate as a response to the worst receiver in the group. Due to the Internet heterogeneity, a single-rate congestion co ntrol affects the overall satisfaction of the receivers in a multicast session. In this paper, we propose a multi-rate replicated scheme where some receivers (instead of the source) are designated to perform data replication for other receivers with lower capacity. To be more scalable and to minimize the bandwidth consumption due to data replication, the partitioning algorithm is per- formed on-the-fly by the routers depending on the feedback they receive. Neither a prior estimation of the receivers capacity is necessary nor a complex computation is required to execute our partitioning algorithm

Secure Routing in Wireless Mesh Networks

Wireless mesh networks (WMNs) have emerged as a promising concept to meet the challenges in next-generation networks such as providing flexible, adaptive, and reconfigurable architecture while offering cost-effective solutions to the service providers. Unlike traditional Wi-Fi networks, with each access point (AP) connected to the wired network, in WMNs only a subset of the APs are required to be connected to the wired network. The APs that are connected to the wired network are called the Internet gateways (IGWs), while the APs that do not have wired connections are called the mesh routers (MRs). The MRs are connected to the IGWs using multi-hop communication. The IGWs provide access to conventional clients and interconnect ad hoc, sensor, cellular, and other networks to the Internet. However, most of the existing routing protocols for WMNs are extensions of protocols originally designed for mobile ad hoc networks (MANETs) and thus they perform sub-optimally. Moreover, most routing protocols for WMNs are designed without security issues in mind, where the nodes are all assumed to be honest. In practical deployment scenarios, this assumption does not hold. This chapter provides a comprehensive overview of security issues in WMNs and then particularly focuses on secure routing in these networks. First, it identifies security vulnerabilities in the medium access control (MAC) and the network layers. Various possibilities of compromising data confidentiality, data integrity, replay attacks and offline cryptanalysis are also discussed. Then various types of attacks in the MAC and the network layers are discussed. After enumerating the various types of attacks on the MAC and the network layer, the chapter briefly discusses on some of the preventive mechanisms for these attacks.Comment: 44 pages, 17 figures, 5 table

Smart network caches : localized content and application negotiated recovery mechanisms for multicast media distribution

Thesis (Ph. D.)--Massachusetts Institute of Technology, Program in Media Arts & Sciences, 1998.Includes bibliographical references (p. 133-138).by Roger George Kermode.Ph.D

Enhanced transport protocols

The book presents mechanisms, protocols, and system architectures to achieve end-to-end Quality-of-Service (QoS) over heterogeneous wired/wireless networks in the Internet. Particular focus is on measurement techniques, traffic engineering mechanisms and protocols, signalling protocols as well as transport protocol extensions to support fairness and QoS. It shows how those mechanisms and protocols can be combined into a comprehensive end-to-end QoS architecture to support QoS in the Internet over heterogeneous wired/wireless access networks. Finally, techniques for evaluation of QoS mechanisms such as simulation and emulation are presented. The book is aimed at graduate and post-graduate students in Computer Science or Electrical Engineering with focus in data communications and networking as well as for professionals working in this area

DIVE on the internet

This dissertation reports research and development of a platform for Collaborative Virtual Environments (CVEs). It has particularly focused on two major challenges: supporting the rapid development of scalable applications and easing their deployment on the Internet. This work employs a research method based on prototyping and refinement and promotes the use of this method for application development. A number of the solutions herein are in line with other CVE systems. One of the strengths of this work consists in a global approach to the issues raised by CVEs and the recognition that such complex problems are best tackled using a multi-disciplinary approach that understands both user and system requirements. CVE application deployment is aided by an overlay network that is able to complement any IP multicast infrastructure in place. Apart from complementing a weakly deployed worldwide multicast, this infrastructure provides for a certain degree of introspection, remote controlling and visualisation. As such, it forms an important aid in assessing the scalability of running applications. This scalability is further facilitated by specialised object distribution algorithms and an open framework for the implementation of novel partitioning techniques. CVE application development is eased by a scripting language, which enables rapid development and favours experimentation. This scripting language interfaces many aspects of the system and enables the prototyping of distribution-related components as well as user interfaces. It is the key construct of a distributed environment to which components, written in different languages, connect and onto which they operate in a network abstracted manner. The solutions proposed are exemplified and strengthened by three collaborative applications. The Dive room system is a virtual environment modelled after the room metaphor and supporting asynchronous and synchronous cooperative work. WebPath is a companion application to a Web browser that seeks to make the current history of page visits more visible and usable. Finally, the London travel demonstrator supports travellers by providing an environment where they can explore the city, utilise group collaboration facilities, rehearse particular journeys and access tourist information data