Maximizing Resource Sharing in WDM Mesh Networks With Path-Based Protection and Sparse OEO Regeneration

We propose a resource-sharing scheme that supports three kinds of sharing scenarios in a WDM mesh network with path-based protection and sparse OEO regeneration. Several approaches are used to maximize the sharing of wavelength-links and OEO regenerators.

VS - Bovine Tuberculosis (Mycobacterium bovis) Surveillance Standards 11/2001

Bovine tuberculosis (TB) is an infectious and communicable granulomatous disease caused by the acidfast bacilli bacteria of Mycobacterium bovis (M. bovis). It is commonly a chronic, debilitating disease, but occasionally may assume an acute, rapidly progressive course. M. bovisis a widespread zoonosis that is global in magnitude and affects nearly all species of vertebrates (cattle, sheep, goats, pigs, bison, buffalo, and camelids.) Disease is spread by direct contact, inhalation of infected droplets expelled from infected lungs, and ingestion of contaminated feed or milk. In most countries, TB is a notifiable disease. Overall, TB has an important world-wide impact on animal industries and human health. Control measures are based on prevention and eradication. Surveillance is a key element for management of preventions and control programs. Surveillance for TB serves the purpose of enabling Veterinary Services to obtain an accurate picture of the scope of the disease in the US livestock populations; in the event of a disease outbreak, the course TB follows in livestock and wildlife populations for a given area over time; and permits timely intervention if the trend observed deviates from what is expected.

Priority-based Lambda Scheduler

Optical networks provide a new dimension to meet the demands of exponentially growing traffic. Optical packet switching requires a good switch architecture, which eliminates the O/E/O conversion as much as possible. Wavelength Division Multiplexing (WDM) provides a breakthrough to exploit the huge bandwidth of the optical fiber. Different applications have different requirements, which necessitate employing differentiated services. This paper presents the idea of a priority-based λ-scheduler, where the packets are differentiated into different classes and services are provided accordingly. For example, class 0 can correspond to non real time applications like email and ftp, while class 1 can correspond to real-time audio and video communications. The architecture is based on that of the λ-scheduler and hence it has the added advantage of reduced component cost by using WDM internally.

Same-Destination-Intermediate Grouping vs. End-to-End Grouping for Waveband Switching in WDM Mesh Networks

We investigate waveband switching (WBS) with different grouping strategies in wavelength-division multiplexing (WDM) mesh networks. End-to-end waveband switching (ETEWBS) and same-destination-intermediate waveband switching (SD-IT-WBS) are analyzed and compared in terms of blocking probability and cost savings. First, an analytical model for ETEWBS is proposed to determine the network blocking probability in a mesh network. For SD-IT-WBS, a simple waveband switching algorithm is presented. An analytical model to determine the network blocking probability is proposed for SD-IT-WBS based on the algorithm. The analytical results are validated by comparing with simulation results. Both results match well and show that ETE-WBS slightly outperforms SD-IT-WBS in terms of blocking probability. On the other hand, simulation results show that SD-IT-WBS outperforms ETE-WBS in terms of cost savings.

Centralized vs. Distributed Connection Management Schemes under Different Traffic Patterns in Wavelength-Convertible Optical Networks

Centralized and Distributed methods are two connection management schemes in wavelength convertible optical networks. In the earlier work, the centralized scheme is said to have lower network blocking probability than the distributed one. Hence, much of the previous work in connection management has focused on the comparison of different algorithms in only distributed scheme or in only centralized scheme. However, we believe that the network blocking probability of these two connection management schemes depends, to a great extent, on the network traffic patterns and reservation times. Our simulation results reveal that the performance improvement (in terms of blocking probability) of centralized method over distributed method is inversely proportional to the ratio of average connection interarrival time to reservation time. After that ratio increases beyond a threshold, those two connection management schemes yield almost the same blocking probability under the same network load. In this paper, we review the working procedure of distributed and centralized schemes, discuss the tradeoff between them, compare these two methods under different network traffic patterns via simulation and give our conclusion based on the simulation data.