Optical Burst Switching - A New Paradigm

Url：http://www.acsu.buffalo.edu/~qiao/nsf_abs.html有两个用于光互联网的基本驱动程序。一个是互联网上多媒体(主要是数据)流量的爆炸性增长，特别是万维网，正如许多人最近发现的那样，它可以在所有时间尺度和各种多路复用级别上突发。另一个是WDM光网络技术的不断进步，这为简化软件(协议)和硬件(电子设备)提供了许多机会，以减少延迟和成本。本研究的目的是探索一种用于波分复用(WDM)光网络的新型交换模式，称为光突发交换(OBS)。OBS在进行单向延迟预留时使用控制(或建立)分组与其对应的数据突发之间的偏移时间，这促进了全光数据传输，并将其与其他单向预留方案和标签/标签交换方案区分开来。通过结合粗粒度光路交换(通过波长路由光路)和细粒度光分组/信元交换的优点，同时避免它们的缺点，OBS可以有效地支持需要许多短暂(或突发)会话的应用，在这些应用期间，需要以高比特率和低端到端延迟来传输大量数据。更重要的是，它将有助于实现建立一个灵活、高效和带宽充足的光纤互联基础设施的愿景，能够通过TCP/IP(以及ATM和其他现有和未来的协议)提供无处不在的服务。在这个项目中，我们将重点研究高效的OBS协议的设计和性能评估，这些协议可以降低突发丢弃概率，支持流量和拥塞控制，以及组播、优先级和容错路由。我们还将研究上层协议(如IP)如何与OBS交互，研究相关的光层控制和管理问题，如资源供应、保护和恢复，并将OBS与其他突发交换和标签/标签交换技术进行比较。最后，我们将研究同步问题、上层与光层接口的性价比设计以及WDM交换机的设计。

URL: http://www.acsu.buffalo.edu/~qiao/nsf_abs.html There are two basic drivers for optical internetworks. One is the explosion of the multimedia (mainly data) traffic over the Internet, especially the World-Wide-Web, which as many discovered recently, can be bursty at all time scales and various multiplexing levels. The other is the continuing advances of WDM optical networking technologies, which offer many opportunities to streamline both software (protocols) and hardware (electronic equipments) for reduced latency and cost. The objective of this research is to explore a novel switching paradigm for WDM (Wavelength Division Multiplexed) optical networks, called Optical Burst Switching (OBS). OBS uses an offset time between a control (or set-up) packet and its corresponding data burst when making one-way delayed reservation, which facilitates all-optical data transfers and distinguishes it from other one-way reservation schemes and label/tag switching schemes. By combining the best of the coarse-grained optical circuit switching (via wavelength routed lightpaths) and the fine-grained optical packet/cell switching, while avoiding their shortcomings, OBS can efficiently support applications requiring many short-lived (or bursty) sessions during which a substantial amount of data needs to be transferred at a high bit rate and with a low end-to-end latency. More importantly, it will help realize the vision of building a flexible, efficient and bandwidth-abundant fiber-optic internetworking infrastructure capable of providing ubiquitous services through TCP/IP (as well as ATM and other existing and future protocols). In this project, we will focus on the design and performance evaluation of efficient OBS protocols that can reduce burst dropping probability, and support flow and congestion control as well as multicasting, priority and fault-tolerant routing. We will also study how upper layer protocols (e.g. IP) interact with OBS, investigate related optical-layer control and managemen t issues such as resource provisioning, protection and restoration, and in addition, compare OBS with other burst switching and lable/tag switching techniques. Finally, we will examine the synchronization problem and the cost-effective designs of the interface between the upper layers and the optical layer as well as the designs of the WDM switches.