The Octopus switch

This chapter1 discusses the interconnection architecture of the Mobile Digital Companion. The approach to build a low-power handheld multimedia computer presented here is to have autonomous, reconfigurable modules such as network, video and audio devices, interconnected by a switch rather than by a bus, and to offload as much as work as possible from the CPU to programmable modules placed in the data streams. Thus, communication between components is not broadcast over a bus but delivered exactly where it is needed, work is carried out where the data passes through, bypassing the memory. The amount of buffering is minimised, and if it is required at all, it is placed right on the data path, where it is needed. A reconfigurable internal communication network switch called Octopus exploits locality of reference and eliminates wasteful data copies. The switch is implemented as a simplified ATM switch and provides Quality of Service guarantees and enough bandwidth for multimedia applications. We have built a testbed of the architecture, of which we will present performance and energy consumption characteristics

A Switch Architecture for Real-Time Multimedia Communications

In this paper we present a switch that can be used to transfer multimedia type of trafJic. The switch provides a guaranteed throughput and a bounded latency. We focus on the design of a prototype Switching Element using the new technology opportunities being offered today. The architecture meets the multimedia requirements but still has a low complexity and needs a minimum amount of hardware. A main item of this paper will be the background of the architectural design decisions made. These include the interconnection topology, buffer organization, routing and scheduling. The implementation of the switching fabric with FPGAs, allows us to experiment with switching mode, routing strategy and scheduling policy in a multimedia environment. The witching elements are interconnected in a Kautz topology. Kautz graphs have interesting properties such as: a small diametec the degree is independent of the network size, the network is fault-tolerant and has a simple routing algorithm

Performance comparison of several priority schemes with priority jumps

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Full duplex switched ethernet for next generation "1553B" -based applications

Over the last thirty years, the MIL-STD 1553B data bus has been used in many embedded systems, like aircrafts, ships, missiles and satellites. However, the increasing number and complexity of interconnected subsystems lead to emerging needs for more communication bandwidth. Therefore, a new interconnection system is needed to overcome the limitations of the MIL-STD 1553B data bus. Among several high speed networks, Full Duplex Switched Ethernet is put forward here as an attractive candidate to replace the MIL-STD 1553B data bus. However, the key argument against Switched Ethernet lies in its non-deterministic behavior that makes it inadequate to deliver hard timeconstrained communications. Hence, our primary objective in this paper is to achieve an accepted QoS level offered by Switched Ethernet, to support diverse "1553B"-based applications requirements. We evaluate the performance of traffic shaping techniques on Full Duplex Switched Ethernet with an adequate choice of service strategy in the switch, to guarantee the real-time constraints required by these specific 1553B-based applications. An analytic study is conducted, using the Network Calculus formalism, to evaluate the deterministic guarantees offered by our approach. Theoretical analysis are then investigated in the case of a realistic "1553B"-based application extracted from a real military aircraft network. The results herein show the ability of profiled Full Duplex Switched Ethernet to satisfy 1553B-like real-time constraints