A router architecture for real-time communication in multicomputer networks

Abstract

Parallel machines have the potential to satisfy the large computational demands of real-time applications. These applications require a predictable communication network, where time-constrained traffic requires bounds on throughput and latency, while good average performance suffices for best-effort packets. This paper presents a new router architecture that tailors low-level routing, switching, arbitration, flow-control, and deadlock-avoidance policies to the conflicting demands of each traffic class. The router implements bandwidth regulation and deadline-based scheduling, with packet switching and table-driven multicast routing, to bound end-to-end delay and buffer requirements for time-constrained traffic while allowing best-effort traffic to capitalize on the low-latency routing and switching schemes common in modern parallel machines. To limit the cost of servicing timeconstrained traffic, the router includes a novel packet scheduler that shares link-scheduling logic across the multiple output ports, while masking the effects of clock rollover on the represention of packet eligibility times and deadlines. Using the Verilog hardware description language and the Epoch silicon compiler, we demonstrate that the router design meets the performance goals of both traffic classes in a single-chip solution. Verilog simulation experiments on a detailed timing model of the chip show how the implementation and performance properties of the packet scheduler scale over a range of architectural parameters.

Composable Flexible Real-time Packet Scheduling for Networks on-Chip

“…However, they need to be adapted for networks on chip due to restricted buffer space in networks on chip. There are also several notable other approaches for quality of service in packet-switched networks [22], [24], [14], [1], [15].…”

Adapting a Main-Stream Internet Switch Architecture for Multihop Real-Time Industrial Networks

“…Rexford, Hall and Shin [49] propose a switch for real-time communication but it was designed to support deadline-based scheduling, which imposes significant hardware changes. Additionally, their switch is not designed for high-speed network backbones either.…”

Online time-constrained scheduling in linear networks

“…In such a scenario, delivering valuable packets on time would mean more profit for the service provider, which should naturally be maximized. Time-constrained traffic is also the common case in real-time applications, such as avionics, industrial process control, and automated manufacturing, which necessitate coping with time constrained communication in interconnection networks [3].…”

“…This occurs for example in a mesh network topology, employing a dimensionorder routing policy. In such a case we can use a bufferless strategy along rows and columns, and perform a conversion to change dimensions (see [3]). Another advantage in considering simple topologies is the fact that they usually adhere to simple routing-path selection.…”