Performance analysis of Gb/s WDM FDDI network

In this paper, we propose a time-token multi-Gb/s Wavelength Division Multiplexing Fibre Distributed Data Interface (WDM/FDDI) architecture and examine its throughput efficiency and delay under heavy load for different network configuration using discrete event simulator

A Novel MicroPhotonic Structure for Optical Header Recognition

In this paper, we propose and demonstrate a new MicroPhotonic structure for optical packet header recognition based on the integration of an optical cavity, optical components and a photoreceiver array. The structure is inherently immune to optical interference thereby routing an optical header within optical cavities to different photo receiver elements to generate the autocorrelation function, and hence the recognition of the header using simple microelectronic circuits. The proof-of-concept of the proposed MicroPhotonic optical header recognition structure is analysed and experimentally demonstrated, and results show excellent agreement between measurements and theory

Economic Denial of Sustainability Attacks Mitigation in the Cloud

Cyber security is one of the most attention seeking issues with the increasing advancement of technology specifically when the network availability is threaten by attacks such as Denial of Service attacks (DoS), Distributed DoS attacks (DDoS), and Economic Denial of Sustainability (EDoS). The loss of the availability and accessibility of cloud services have greater impacts than those in the traditional enterprises networks. This paper introduces a new technique to mitigate the impacts of attacks which is called Enhanced DDoS-Mitigation System (Enhanced DDoS-MS) that helps in overcoming the determined security gap. The proposed technique is evaluated experimentally and the result shows that the proposed method adds lower delays as a result of the enhanced security. The paper also suggests some future directions to improve the proposed framework

Novel Queueing Model for Multimedia over Downlink in 3.5G Wireless Network

In this paper, the model for multimedia transmission over downlink in 3.5G wireless network in terms of a queue with two priority classes, one of which has time priority while the another has space priority, is formulated. The input is described by the Batch Marked Markov Arrival Process (BMMAP ). Service time distributions are of PH (phase) type dependent on the class of a customer. The bu#er is finite, but the customers of a class having higher priority for taking into the service from a bu#er (time priority) can occupy only a part of this bu#er. Queueing system's behavior is described in terms of multi-dimensional continuous time skip-free to the left Markov chain. It allows to exploit an e#ective algorithm for calculation of the stationary distribution of the queueing system. Loss probability for customers of both classes is calculated

Throughput and Delay Optimization in WDM FDDI optical Network

The rapidly growing Internet traffic are driving the demands for higher transmission capacity and higher processing speed, especially for the backbone networks. To support such bandwidth usage an optical Fiber Distributed Data Interface Wavelengtg Division Multiplexed (FDDI/WDM) network is proposed, wherein the wavelength channels are amplified using Erbium-Doped Fiber Amplifiers (EDFA\u27s) to compensate for the losses over the optical fiber span. In this paper we investigate the network performance for both asynchronous and synchronous transmissions by measuring the amplified spontaneous emission (ASE) along the ring, the optical signal to noise ratio (OSNR) and the electrical SNR at different destinations. The effects of various network parameters such as synchronous bandwidth allocation and Target Token Ration Time (TTRT) on the network perfomrance are also presented. Results show that when FDDI is used in conjunction with WDM higher throughut and less delay are simutaneously achieved in comparison with FDDI standard networks

Dynamic Buffer Management for Multimedia Services in 3.5G Wireless Networks

Abstract — This paper presents and investigates a dynamic buffer management scheme for QoS control of multimedia services in a 3.5G wireless system i.e. the High Speed Downlink Packet Access (HSDPA). HSDPA was introduced to enhance UMTS for high-speed packet switched services. With HSDPA, packet scheduling and HARQ mechanisms in the base station require data buffering at the air interface thus introducing a potential bottleneck to end-to-end communication. Hence, for multimedia services with multiplexed parallel diverse flows such as video and data in the same end-user session, buffer management schemes in the base station are essential to support end-to-end QoS provision. We propose a dynamic buffer management scheme for HSDPA multimedia sessions with aggregated real-time and non real-time flows in the paper. The end-to-end performance impact of the scheme is evaluated with an example multimedia session comprising a real-time streaming flow concurrent with TCP-based non real-time flow via extensive HSDPA simulations. Results demonstrate that the scheme can guarantee the end-to-end QoS of the real-time streaming flow, whilst simultaneously protecting non real-time flow from starvation resulting in improved end-to-end throughput performance. Index Terms — HSDPA, UMTS, QoS, buffer management, real-time streaming, multimedia traffic. I

End-to-End QoS Enhancement ofHSDPA End-User Multi-flow Traffic Using RAN Buffer Management

High speed downlink packet access (HSDPA) was introduced to UMTS radio access segment to provide higher capacity for new packet switched services. As a result, packet switched sessions with multiple diverse traffic flows such as concurrent voice and data, or video and data being transmitted to the same user are a likely commonplace cellular packet data scenario. In HSDPA, radio access network (RAN) buffer management schemes are essential to support the end-to-end QoS of such sessions. Hence in this paper we present the end-to-end performance study of a proposed RAN buffer management scheme for multi-flow sessions via dynamic system-level HSDPA simulations. The scheme is an enhancement of a time-space priority (TSP) queuing strategy applied to the node B MAC-hs buffer allocated to an end user with concurrent real-time (RT) and non-real-time (NRT) flows during a multi-flow session. The experimental multi- flow scenario is a packet voice call with concurrent TCP-based file download to the same user. Results show that with the proposed enhancements to the TSP-based RAN buffer management, end-to-end QoS performance gains accrue to the NRT flow without compromising RT flow QoS of the same end user session