UltraFlow dual-mode access networks [electronic resource] : architecture and management
Keywords: Electrical Engineering.

In the past few decades, electronic packet switching (EPS) has been widely accepted in communication systems for its high efficiency of transmitting data in small sizes. However, its packet-based switching mechanism requires routing and buffering for each of the packets derived from the same file, even though these packets are known to be for the same recipient(s). The computation power consumed by such repeated electronic processing increases with file size, and imposes a tremendous burden on the routing nodes that are already stressed by the rapidly increasing network traffic. To prevent excessive transmission delays caused by congestion at the routing nodes, expensive electronics need to be installed for higher system capacity. This makes the system less cost-effective and energy-efficient. Therefore, the Optical Flow Switched (OFS) network was proposed as a complement to the EPS network for large network transactions. In an OFS network, a dedicated end-to-end lightpath is reserved for a certain period prior to the transmission. As a result, no intermediate electronic buffering and routing are required, and the electronic processing power can be saved for better cost-effectiveness and energy efficiency. In this dissertation, we propose the UltraFlow access network that enables OFS in the access network domain, and provides dual-mode service, optical IP and Flow, to the end users. The dual-mode service retains the advantages of an IP service based on the EPS network for transmission of small data such as emails, while providing the Flow service based on the OFS network for higher transmission efficiency of data in large volume. Two novel network architectures and one management framework are proposed to achieve lower service delays, better energy efficiency and higher cost-effectiveness in the UltraFlow access network. The reconfigurable long-reach (R-LR) UltraFlow access architecture extends the provision of Flow service to connect large number of users scattered in a wide area with network resources consolidated in a single central office. It consists of two reconfigurable switching modules for dynamic control of Flow and IP resource sharing among different user groups. This helps improve the energy efficiency and cost-effectiveness of the R-LR UltraFlow access network. We also investigate the quasi-passive reconfigurable (QPAR) node-based UltraFlow access architecture. The novel network node offers much higher flexibility in wavelength routing and power splitting, while remaining passive when there is no reconfiguration. Remote powering and control of the QPAR node has been experimentally demonstrated with a prototype circuit. The unique characteristics of QPAR facilitate the overlay of Flow service over IP services deployed with different technologies. It is also found to be highly effective in suppressing excessive service delays caused by unbalanced traffic demands and intensive multicast Flow traffic. On the network management side, we propose a resource sharing framework for the UltraFlow access network that dynamically offloads excessive Flow traffic to the underutilized optical IP channels. Both numerical and experimental results indicate that the proposed framework can effectively reduce the service delay in the Flow channel in different scenarios.