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6   Layer Anatomy: what are the pieces of a layer?

This is a description of the standard pieces of a Ensemble layer. This description is meant to serve as a general introduction the standard ``idioms'' that appear in layers. Because all layers follow the same general structure, we present a single documentation of that structure, so that comments in a layer describe what is particular to that layer rather than repeating the features each has in common with all the others. Comments on additional information that would be useful here would be appreciated.

6.1   Design Goals

A design goal of the protocol layers is to include as little Ensemble-specific infrastructure is present in the layers. For instance, none of the layers embody notions of synchronization, messages operations, of event scheduling. In fact, the only Ensemble-specific modules used by layers are the Event and the View modules.

6.2   Notes

Some general notes on layers:

6.3   Values and Types

Listed below are the values and types commonly found in a layer, listed in the usual order of occurrence. For each object we give a description of its typical use and whether or not it is exported out of the layer.


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