The growth in the volume of Internet traffic and the increasing variety of Internet applications require Internet backbone networks to be scalable and provided sophisticated quality of service (QoS) capabilities. Internet backbone routers have evolved to achieve sub-Tbps switching capacity in a single unit, but their switch architectures have limited scalability, causing QoS to degrade as the switches get bigger. Hence, we propose a large-scale IP and lambda integrated router architecture with scalable switches. We first describe the system architecture of our proposed backbone router and clarify the requirements for its switching capabilities to meet near-future demands. The new switch architecture, using crossbar-based switching fabrics and optical interconnection devices, meets the requirements for a backbone router to scale up to 82 Tbps and enable light path switching as well as packet switching. The routing tag and its usage algorithm in the switch, and packaging issues, including the quantity of hardware required for expansion, are also discussed.

A switching network construction scheme for a fast packet switching system, which is expected to provide multi-media services efficiently and economically, is proposed. The proposed packet switch has RAM as a shared buffer. Its access is assigned to input and output ports dynamically in order to fully utilize limited memory time. This enables packet switches to flexibly accommodate packet links having different bit-rates. An asynchronous data transfer technique is also incorporated into inter-switch links. This switching network can dynamically alter the inter-switch link speed, according to the demanded flow. The dynamism of this simple hardware contributes greatly to better packet transfer quality. This paper describes switch architecture, multi-stage packet switching network construction which can handle any combination of packet flow without centralized switch resource management, and simulated packet transport characteristics of a multi-stage switching network. The simulation results show that the proposed switching network gives good packet transport quality, in terms of packet delay and loss. Finally, the congestion mechanism is analyzed.

With the spread of broadband and wireless Internet access, there is a growing need for a nomadic network environment that enables the use of network services anywhere, via various access media. In a nomadic network environment, however, the connectivity is decreased because users move among different access networks, and the bandwidth is narrow and fluctuating, especially for radio propagation in wireless networks. To solve these problems, we propose a multilink system with three key functions: IPinIP tunneling, dynamic distribution of packets, and reordering of distributed packets. In particular, our distribution function includes a novel algorithm based on available bandwidth estimation. A prototype of our system was evaluated through experiments using real wireless environments and its efficiency is discussed.