A layered MIMD Communication Processor
MIMD systems consist of many processing nodes which are connected by an interconnection network. The communication between nodes through this network is supported by special hardware; besides a dataprocessor, each node includes a communication processor. The number of design decisions for these communication processors israther large, which is illustrated by the many different communication processor designs made and proposed in the past.
Inspired by the OSI communication layer model, this paper systematically introduces the most important design parameters for communication processors in message passing distributed memory MIMD systems. The communication layer model distinguishes physical, data link, network, and transport layers. Each layer has its own functionality (realized by using lower layers) and implementation. For every layer a set of parameters can be discriminated which characterize thelayer: virtual layer support, entity representation, buffering, flow control,routing, and error handling.
Together, all design parameters span a multidimensional design space. Points in this space are clarified through classification of a number of existing communication processors. The layered classification model facilitates comparisonof various communication processor designs and allows simple recognition of similarities and differences.
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