Optical Multicast Routing Under Light Splitter Constraints

During the past few years, we have observed the emergence of new applications that use multicast transmission. For a multicast routing algorithm to be applicable in optical networks, it must route data only to group members, optimize and maintain loop-free routes, and concentrate the routes on a subset of network links. For an all-optical switch to play the role of a branching router, it must be equipped with a light splitter. Light splitters are expensive equipments and therefore it will be very expensive to implement splitters on all optical switches. Optical light splitters are only implemented on some optical switches. That limited availability of light splitters raises a new problem when we want to implement multicast protocols in optical network (because usual multicast protocols make the assumption that all nodes have branching capabilities). Another issue is the knowledge of the locations of light splitters in the optical network. Nodes in the network should be able to identify the locations of light splitters scattered in the optical network so it can construct multicast trees. These problems must be resolved by implementing a multicast routing protocol that must take into consideration that not all nodes can be branching node. As a result, a new signaling process must be implemented so that light paths can be created, spanning from source to the group members

Internet Protocol (IP) Multicast: Final Report

Report presents the results of the Institute for Simulation and Training\u27s implementation and integration of new protocols into the Testbed for Research in Distributed Interactive Simulation (TRDIS) testbed, especially the Internet Protocol (IP) Multicast (IPmc) and Internet Group Management Protocol network protocols, into a simulation application

Hastily Formed Networks (HFN) As an Enabler for the Emergency Response Community

The effects of natural or manmade disasters in communications infrastructures are so severe that immediately after the disaster the emergency responders are unable to use them. In addition, some areas do not have any useful infrastructure at all. To bridge this gap in communications, a need exists for a reliable technology not dependent on the existing infrastructure. This thesis focuses on first identifying the problem of communications gaps during natural or manmade disasters and reviewing the impact and potential benefit of implementing a solution based on the Hastily Formed Networks (HFN) model. The research explores the different technological solutions to solve this problem by evaluating documentation for commercial off-the-shelf technologies (COTS). Additionally, the thesis reviews the results of field experimentation conducted to evaluate the performance of these technologies in the field. The ultimate goal is to introduce the HFN concept as an enabler for the Emergency Response Community (ERC). Throughout this research, the focus revolves around testing COTS technologies. The research provides emergency responders with the background knowledge to make decisions on how to best bridge the gap of lack of communications under austere environments, and therefore enable them to provide better response.http://archive.org/details/hastilyformednet109456762Lieutenant Commander, United States Nav

Multicast Services for Multimedia Collaborative Applications

This work aims at providing multicast services for multimedia collaborative applications over large inter-networks such as the Internet. Multimedia collaborative applications are typically of small group size, slow group membership dynamics, and awareness of participants\u27 identities and locations. Moreover, they usually consist of several components such as audio, video, shared whiteboard, and single user application sharing engines that collectively help make the collaboration session successful. Each of these components has its demands from the communication layer that may differ from one component to another. This dissertation identifies the overall characteristics of multimedia collaborative applications and their individual components. It also determines the service requirements of the various components from the communication layer. Based on the analysis done in the thesis, new techniques of multicast services that are more suitable for multimedia collaborative applications are introduced. In particular, the focus will be on multicast address management and connection control, routing, congestion and flow control, and error control. First, we investigate multicast address management and connection control and provide a new technique for address management based on address space partitioning. Second, we study the problem of multicast routing and introduce a new approach that fits the real time nature of multimedia applications. Third, we explore the problem of congestion and flow control and introduce a new mechanism that takes into consideration the heterogeneity within the network and within the processing capabilities of the end systems. Last, we exploit the problem of error control and present a solution that supports various levels of error control to the different components within the collaboration session. We present analytic as well as simulation studies to evaluate our work, which show that our techniques outperform previous ones

Congestion Control Mechanisms for Internet Multicast Transport Protocols.

Internet Multicasting has emerged in the last few years as the inevitable method for efficiently delivering replicated data to multiple recipients in large scale internets. More specifically, Reliable Multicast Transport Protocols have been the subject of intensive research in recent years. The goal of such research was mainly to develop reliable and scalable protocols to efficiently and reliably deliver data to receivers, and at the same time reduce congestion on the network. In this research, we propose a new generic family of protocols, called the K family of protocols, that focus on congestion control by reducing the processing requirements on receivers to O (1), while being able to tune the processing requirements on the sender to the sender\u27s processing capability. The concept of Local Recovery is then applied to the K protocol family, achieving even further improvement in processing requirements, especially at the sender. In all cases, processing requirements at the sender and at the receivers are analytically studied. We also introduce a new concept that attempts to detect packet loss and repair it before control packets cause implosions at the sender or at the receivers. Finally, some numerical results are presented to show the relative reduction in processing requirements in comparison with other prominent generic classes of protocols

A scalable decentralized group membership service for an asynchronous environment

This thesis presents a globally scalable, decentralized group membership service to manage client process groups operating in a distributed, asynchronous environment. This group membership service is totally scalable, handling process groups spanning a single LAN to groups spanning the entire global Internet equally well. It provides for nested and overlapping groups, as well as multiple groups residing on a single LAN. It also provides various Quality of Service selections which permit individual groups to be configured for an optimal balance between high quality with strong consistency semantics for group membership, and weaker consistency semantics with reduced complexity and latency. This thesis describes the complete design of the protocol used to implement the group membership service. It presents the design requirements and goals, and underlying assumptions about the network. The various Quality of Service selections provided by the group membership service are described in detail, as well as the interface between the process groups, the membership service, and the underlying network. The use of a hierarchical architecture to obtain the desired scalability, flexibility, and robustness is explained. A proof of correctness for the protocol is presented, and a partial implementation of the group membership service is describedhttp://archive.org/details/scalabledecentra00neelLieutenant, United States NavyApproved for public release; distribution is unlimited

Optimum hybrid error correction scheme under strict delay constraints

In packet-based wireless networks, media-based services often require a multicast-enabled transport that guarantees quasi error free transmission under strict delay constraints. Furthermore, both multicast and delay constraints deeply influence the architecture of erasure error recovery (EER). Therefore, we propose a general architecture of EER and study its optimization in this thesis. The architecture integrates overall existing important EER techniques: Automatic Repeat Request, Forward Error Correction and Hybrid ARQ techniques. Each of these EER techniques can be viewed as a special case of Hybrid Error Correction (HEC) schemes. Since the Gilbert-Elliott (GE) erasure error model has been proven to be valid for a wide range of packet based wireless networks, in this thesis, we present the general architecture and its optimization based on the GE channel model. The optimization target is to satisfy a certain target packet loss level under strict delay constraints efficiently. Through the optimization for a given real-time multicast scenario, the total needed redundancy information can be minimized by choosing the best HEC scheme automatically among the entire schemes included in the architecture. As a result, the performance of the optimum HEC scheme can approach the Shannon limit as closely as possible dynamically according to current channel state information.In Paket-basierten drahtlosen Netzwerken benötigen Medien-basierte Dienste oft Multicast-fähigen Transport, der quasi-fehlerfreie Übertragung unter strikten Zeitgrenzen garantiert. Außerdem beeinflussen sowohl Multicast als auch Zeitbegrenzungen stark die Architektur von Auslöschungs-Fehlerschutz (Erasure Error Recovery, EER). Daher stellen wir eine allgemeine Architektur der EER vor und untersuchen ihre Optimierung in dieser Arbeit. Die Architektur integriert alle wichtigen EER-Techniken: Automatic Repeat Request, Forward Error Correction und Hybrid ARQ. Jede dieser EER-Techniken kann als Spezialfall der Hybrid Error Correction (HEC) angesehen werden. Da das Gilbert-Elliot (GE) Auslöschungs-Fehler-Modell für einen weiten Bereich von Paket-basierten drahtlosen Netzwerken als gültig erwiesen wurde, präsentieren wir in dieser Arbeit die allgemeine Architektur und deren Optimierung basierend auf dem GE Kanalmodell. Zweck der Optimierung ist es, eine gewisse Ziel-Paketfehlerrate unter strikten Zeitgrenzen effizient zu erreichen. Durch die Optimierung für ein gegebenes Echtzeit-Mutlicast-Szenario kann die insgesamt benötigte Redundanz-Information minimiert werden. Dies erfolgt durch automatische Auswahl des optimalen HEC Schemas unter all den Schemata, die in die Architektur integriert sind. Das optimale HEC-Schema kann die Shannon Grenze so nahe wie möglich, dynamisch, entsprechend dem derzeitigen Kanalzustand, erreichen