The internet: A global telecommunications solution?

The provision and support of new distributed multimedia services are of prime concern for telecommunications operators and suppliers. Clearly, the potential of the latest Internet protocols to contribute communications components is of considerable interest to them. In this article we first review some of the new types of application and their requirements, and identify the need to support applications that have strict QoS requirements, the so-called critical applications. We review two proposals for enhancing the Internet service architecture. In addition to the integrated services work of the IETF, we look at the more recent proposals for differentiated services in the Internet. We then individually review recent protocol developments proposed to improve the Internet, and to support real-time and multimedia communications. These are IPv6 (the new version of the Internet Protocol), Resource reSerVation Protocol, and Multiprotocol Label Switching, respectively. In each case, we attempt to provide critical reviews in order to assess their suitability for this purpose. Finally, we indicate what the basis of the future infrastructure might be in order to support the full variety of application requirements

BGRP: A Tree-Based Aggregation Protocol for Inter-domain Reservations

Resource reservation needs to accommodate the rapidly growing size and increasing service diversity of the Internet. Recently, hierarchical architectures have been proposed that provide domain-level reservation.However, it is not clear that these proposals can set up and maintain reservations in an efficient and scalable fashion. In this paper, we describe a distributed architecture and protocol,called the Border Gateway Reservation Protocol (BGRP), for inter-domain resource reservation that can scale in terms of message processing load. state storage and bandwidth. Each stub or transit domain may use its own intra-domain resource reservation protocol. BGRP builds a sink tree for each of the stub domains. Each sink tree aggregates bandwidth reservations from all data sources in the network.Since backbone routers only maintain the sink tree information, the total number of reservation states at each router scales, in the worst case, linearly with the number of domains in the Internet. BGRP relies on differentiated services for data forwarding. As a result, the number of packet classifier entries is small, not the number of micro-flows.To reduce the protocol message traffic, routers may reserve domain bandwidth beyond the current load so that sources can join or leave the tree or change their reservation without having to send messages all the way to the root for every such change. We use``soft state'' to maintain reservations. In contrast to RSVP, refresh messages are delivered reliably, allowing us to reduce the refresh frequency

Loop detection and prevention mechanism in multiprotocol label switching

The extended color thread algorithm is based on running a thread hop by hop before the labels are distributed inside a MPLS Cloud Since the path for the data packets is set beforehand, the loop formation occurs at the control path. The shortest paths between selected source and destination have been calculated using Dijkstra\u27s shortest path algorithm and threads are allowed to extend through the routers. With the passage of each next hop, a distributed procedure is executed within the thread, generating a unique color at nodes. This keeps a track on router\u27s control path and at the same time ensures that no loop formation occurs. In loop prevention mode, a router transmits a label mapping, when it rewinds the thread for that particular LSP. Likewise, if a router operates in loop detection mode, it returns a label-mapping message without a thread object, after receiving a colored thread. The scheme is a loop prevention scheme, thus, ensuring loop detection and loop mitigation. The same algorithm is then extended to a proposed MPLS environment with global label space. (Abstract shortened by UMI.)

Wireless industrial monitoring and control networks: the journey so far and the road ahead

While traditional wired communication technologies have played a crucial role in industrial monitoring and control networks over the past few decades, they are increasingly proving to be inadequate to meet the highly dynamic and stringent demands of today’s industrial applications, primarily due to the very rigid nature of wired infrastructures. Wireless technology, however, through its increased pervasiveness, has the potential to revolutionize the industry, not only by mitigating the problems faced by wired solutions, but also by introducing a completely new class of applications. While present day wireless technologies made some preliminary inroads in the monitoring domain, they still have severe limitations especially when real-time, reliable distributed control operations are concerned. This article provides the reader with an overview of existing wireless technologies commonly used in the monitoring and control industry. It highlights the pros and cons of each technology and assesses the degree to which each technology is able to meet the stringent demands of industrial monitoring and control networks. Additionally, it summarizes mechanisms proposed by academia, especially serving critical applications by addressing the real-time and reliability requirements of industrial process automation. The article also describes certain key research problems from the physical layer communication for sensor networks and the wireless networking perspective that have yet to be addressed to allow the successful use of wireless technologies in industrial monitoring and control networks

A Priority Rate-Based Routing Protocol for wireless multimedia sensor networks

The development of affordable hardware has made it possible to transmit multimedia data over a wireless medium using sensor devices. Deployed sensors span larger geographical areas, generating different kinds of traffic that need to be communicated either in real-time or non-real-time mode to the sink. The tiny sized design of sensor nodes has made them even more attractive in various environments as they can be left unattended for longer periods. Since sensor nodes are equipped with limited resources, newer energy-efficient protocols and architectures are required in order to meet requirements within their limited capabilities when dealing with multimedia data. This is because multimedia applications are characterized by strict quality of service requirements that distinctively differentiate them from other data types during transmission. However, the large volume of data produced by the sensor nodes can easily cause traffic congestion making it difficult to meet these requirements. Congestion has negative impacts on the data transmitted as well as the sensor network at large. Failure to control congestion will affect the quality of multimedia data received at the sink and further shorten the system lifetime. Next generation wireless sensor networks are predicted to deploy a different model where service is allocated to multimedia while bearing congestion in mind. Applying traditional wireless sensor routing algorithms to wireless multimedia sensor networks may lead to high delay and poor visual quality for multimedia applications. In this research, a Priority Rate-Based Routing Protocol (PRRP) that assigns priorities to traffic depending on their service requirements is proposed. PRRP detects congestion by using adaptive random early detection (A-RED) and a priority rate-based adjustment technique to control congestion. We study the performance of our proposed multi-path routing algorithm for real-time traffic when mixed with three non real-time traffic each with a different priority: high, medium or low. Simulation results show that the proposed algorithm performs better when compared to two existing algorithms, PCCP and PBRC-SD, in terms of queueing delay, packet loss and throughput

Models and Solution Algorithms for Asymmetric Traffic and Transit Assignment Problems

Modeling the transportation system is important because it provides a “common ground” for discussing policy and examining the future transportation plan required in practices. Generally, modeling is a simplified representation of the real world; however, this research added value to the modeling practice by investigating the asymmetric interactions observed in the real world in order to explore potential improvements of the transportation modeling. The Asymmetric Transportation Equilibrium Problem (ATEP) is designed to precisely model actual transportation systems by considering asymmetric interactions of flows. The enhanced representation of the transportation system by the ATEP is promising because there are various asymmetric interactions in real transportation such as intersections, highway ramps, and toll roads and in the structure of the transit fares. This dissertation characterizes the ATEP with an appropriate solution algorithm and its applications. First, the research investigates the factors affecting the convergence of the ATEP. The double projection method is applied to various asymmetric types and complexities in the different sizes of networks in order to identify the influential factors including demand intensities, network configuration, route composition between modes, and sensitivity of the cost function. Secondly, the research develops an enhancement strategy for improvement in computational speed for the double projection method. The structural characteristics of the ATEP are used to develop the convergence enhancement strategy that significantly reduces the computational burdens. For the application side, instances of asymmetric interactions observed in in-vehicle crowding and the transit fare structure are modeled to provide a suggestion on policy approach for a transit agency. The direct application of the crowding model into the real network indicates that crowd modeling with multi user classes could influence the public transportation system planning and the revenue achievement of transit agencies. Moreover, addition of the disutility factor, crowding, not always causes the increase of disutility from the transit uses. The application of the non-additive fare structure in the Utah Transit Authority (UTA) network addresses the potential of the distance-based fare structure should the UTA make a transition to this fare structure from their current fare model. The analysis finds that the zero base fare has the highest potential for increasing the transit demand. However, collecting less than $0.50 with a certain buffer distance for the first boarding has potential for attracting the users to UTA\u27s transit market upon the fare structure change

Traffic engineering multi-layer optimization for wireless mesh network transmission a campus network routing protocol transmission performance inhancement

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel UniversityThe wireless mesh network is a potential network for the future due to its excellent inherent characteristic for dynamic self-healing, self-configuration and self-organization. It also has the advantage of easy interoperability networking and the ability to form multi-linked ad-hoc networks. It has a decentralized topology, is cheap and highly scalable. Furthermore, its ease in deployment and easy maintenance are other inherent networking qualities. These aforementioned qualities of the wireless mesh network bring advantages to transmission capability of heterogeneous networks. However, transmissions in wireless mesh network create comparative performance based challenges such as congestion, load-balancing, scalability over increasing networks and coverage capacity. Consequently, these challenges and problems in the routing and switching of packets in the wireless mesh network routing protocols led to a proposal on the resolution of these failures with a combination algorithm and a management based security for the network and its transmitted packets. There are equally contentious services like reliability of the network and quality of service for real-time multimedia traffic flows with other challenges such as path computation and selection in the wireless mesh network. This thesis is therefore a cumulative proposal to the resolution of the outlined challenges and open research areas posed by using wireless mesh network routing protocol. It advances the resolution of these challenges in the mesh environment using a hybrid optimization – traffic engineering, to increase the effectiveness and the reliability of the network. It also proffers a cumulative resolution of the diverse contributions on wireless mesh network routing protocol and transmission. Adaptation and optimization are carried out on the wireless mesh network designed network using traffic engineering mechanism and technique. The research examines the patterns of mesh packet transmission and evaluates the challenges and failures in the mesh network packet transmission. It develops a solution based algorithm for resolutions and proposes the traffic engineering based solution.. These resultant performances and analysis are usually tested and compared over wireless mesh IEEE802.11n or other older proposed documented solution. This thesis used a carefully designed campus mesh network to show a comparative evaluation of an optimal performance of the mesh nodes and routers over a normal IEE802.11n based wireless domain network to show differentiation by optimization using the created algorithms. Furthermore, the indexes of performance being the metric are used to measure the utility and the reliability, including capacity and throughput at the destination during traffic engineered transmission. In addition, the security of these transmitted data and packets are optimized under a traffic engineered technique. Finally, this thesis offers an understanding to the security contribution using traffic engineering resolution to create a management algorithm for processing and computation of the wireless mesh networks security needs. The results of this thesis confirmed, completed and extended the existing predictions with real measurement