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This paper briefly reviews the distributed communication network concept in which each station is connected to all adjacent stations rather than to a few switching points, as in a centralized system. The payoff for a distributed configuration in terms of survivability in the cases of enemy attack directed against nodes, links or combinations of nodes and links is demonstrated. A comparison is made between diversity of assignment and perfect switching in distributed networks, and the feasibility of using low-cost unreliable communication links, even links so unreliable as to be unusable in present type networks, to form highly reliable networks is discussed. The requirements for a future all-digital data distributed network which provides common user service for a wide range of users having different requirements is considered. The use of a standard format message block permits building relatively simple switching mechanisms using an adaptive store-and-forward routing policy to handle all forms of digital data including digital voice. This network rapidly responds to changes in the network status. Recent history of measured network traffic is used to modify path selection. Simulation results are shown to indicate that highly efficient routing can be performed by local control without the necessity for any central, and therefore vulnerable, control point.

This Memorandum, the sixth in the series entitled 'On Distributed Communications,' is a detailed consideration of a possible design for the network's communications links, based on the use of microwave repeater stations. Of the several possible link designs presented in Vol. I of the series, the mini-cost microwave appears least expensive. The mini-cost system is designed solely for use in transmitting digital signals within the Distributed Adaptive Message Block Network. However, many of its specific facets might be of use in other microwave applications. Costs are factored out in detail, demonstrating more specifically the advantages of the microwave link. Two receiver designs further facilitate evaluation of the general proposal. The two other principal components of the distributed network--the Switching Node and the Miltiplexing Station-are described in Vols. VII and VIII in the series. (Author)

One in a series of eleven Memoranda detailing the Distributed Adaptive Message Block Network, a proposed digital data communications system based on a distributed network concept.

This Memorandum, the first in the series entitled On Distributed Communications, introduces the system concept and outlines the requirements for and design considerations of a digital data communications system based on the distributed concept, especially as regards implications for such systems in the 1970s. In particular, the Memorandum is directed toward examining the use of redundancy as one means of building communications systems to withstand heavy enemy attacks. While slightly survivable and reliable communications systems are of primary interest to those in the military concerned with automating command and control functions, the basic notions are also of interest to communications systems planners and designers having need to transmit digital data. (Author)

Considers the security aspects of a system of the type in which all imputs are treated as classified. Describes the safeguards to be built into the network, and evaluates the premise that the existence of ''spies'' within the supposedly secure system must be anticipated. Security provisions are based on the belief that protection is best obtained by raising the ''price'' of espied information to a level which becomes excessive. The treatment of the subject is itself unclassified. (Author)

One in a series of eleven Memoranda detailing the Distributed Adaptive Message Block Network, a proposed digital data communications system based on a distributed network concept.

We are witnessing a growing appreciation that communications systems which transmit analog signals (such as voice) could benefit if designed as all-digital computer-like assemblies. This new view of communications as a digital process is a minority viewpoint in the communications industry; but a minority which is rapidly increasing. I believe that the direction of all-digital-communications-networks development will be towards true, all-digital systems including both transmission and switching. Our present analog techniques may be on their way out. Many of the systems cannot be built entirely out of LSI components. Some microwave elements, for example, will still require individual components such as varactor diodes and strip-transmission lines; but the bulk of circuitry could be in LSI modules. (Author)

This Memorandum, the eleventh and final volume in the series entitled 'On Distributed Communications,' summarizes the development of the system proposal. The more salient features of the system, presented in much greater detail in the other Memoranda in the series, are summarized, allowing the casual reader to obtain a general overview of the network. A reading of the introductory Memorandum in the series and the present Memorandum should suffice for a general understanding of the proposed Distributed Adaptive Message Block Network. (Author)

An examination of the usefulness of existing FM and TV stations as links in an emergency post-attack communications system.

This report details the Distributed Adaptive Message Block Network, a proposed digital data communications system based on a distributed network concept.