Optical Communication Networks for the Next-Generation Internet

Computer and telecommunication networks are changing the world dramatically and will continue to do so in the foreseeable future. The Internet, primarily based on packet switches, provides very flexible data services such as e-mail and access to the World Wide Web. The Internet is a variable-delay, variable- bandwidth network that provides no guarantee on quality of service (QoS) in its initial phase. New services are being added to the pure data delivery framework of yesterday. Such high demands on capacity could lead to a “bandwidth crunch” at the core wide-area network, resulting in degradation of service quality. Fortunately, technological innovations have emerged which can provide relief to the end user to overcome the Internet’s well-known delay and bandwidth limitations. At the physical layer, a major overhaul of existing networks has been envisaged from electronic media (e.g., twisted pair and cable) to optical fibers - in wide-area, metropolitan-area, and even local-area settings. In order to exploit the immense bandwidth potential of optical fiber, interesting multiplexing techniques have been developed over the years.

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.

Departmentalization in the 5th Grade Classroom: Re-thinking the Elementary School Model

In this action research study of my 5th grade classroom, I investigated the benefits of a modified block schedule and departmentalization. The research consisted of dividing the 5th grade curriculum into three blocks. Each block consisted of two primary subject areas: Mathematics was paired with Social Studies, Reading was paired with Health, and Writing was paired with Science. These groupings were designed to accommodate district time-allotment requirements and the strengths of each teacher within the 5th grade team. Thus, one teacher taught all of the Mathematics and Social Studies, another all of the Reading and Health, and another all of the Writing and Science. Students had classes with each teacher, each school day. I discovered that this departmentalization had many benefits to both students and teachers. As a result of this research, we plan to continue with our new schedule and further develop it to more fully exploit the educational and professional advantages we found to be a part of the project.