On Distributed Communications Series

V. History, Alternative Approaches, and Comparisons

Contents
Preface
Summary
I. Introduction
II. The Distributed Network Concept
III. Early History
IV. Specific Hardware Proposals

V. Conclusions

There is no single "distributed network." Many highly different systems can all be correctly called distributed, and some of these can be categorized as using perfect switching. Sufficient simulation has been run to predict the effects of overt destruction upon those using perfect switching and those using only diversity-of-assignment techniques. Generally, the more "perfect" the switching, the greater the survivability.

While those systems that use only diversity of assignment over large spanning distances are more vulnerable than those that use perfect switching, the essentially simple diversity-of-assignment technique appears satisfactory when only short spanning distances need to be considered.

The survivability of other switched networks that fall somewhere between these two known points of system performance cannot be determined without a specific examination being made. After many more such specific intermediate systems are examined in detail, we will have more known points upon which to interpolate performance characteristics of other proposed systems under overt attack.

It will always be necessary, though, to examine each switched system separately to determine its ability to withstand sophisticated tampering.

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Appendix A. Summary Charts
Appendix B. The DDD System
List of Publications in the Series