Techniques: Survey of computer communications loop networks: Part 1

A loop (ring) system is proposed for distributed computer networks which: i) allows simultaneous transmission of variable-length message frames, 2) minimizes loop access and transmission times, and 3) provides a form of automatic traffic regulation. The ring interface transmitter which performs these three functions is described, and a conceptual model of its operation is developed. The model illustrates a technique by which the ring interface transmitter can delay incoming messages by hardware buffering just long enough for a variable-length output message to be placed on the loop. It is shown how advantage can be taken of gaps between incoming messages to clear out the delay buffer and to make room for future outgoing messages. It is further demonstrated that an interesting form of automatic message traffic regulation results from use of the proposed technique. Possible hardware implementations of the model are also considered, using a variable-length shift register for the incoming message delay buffer. The probable effects of the proposed technique on message transmission are discussed, and ongoing analytic and simulation studies are described.

A loop network for simultaneous transmission of variable-length messages

Techniques: Survey of computer communications loop networks: Part 2

A f a u l t t o l e r a n t loop computer network system is proposed, where f a u l t to le rance of t h e system is a t t a i n e d by g i v i n g autonauy for f a u l t de tec t ion , recovery and t ransmiss ion t o every network cont ro l processor (NCP) . For evaluating f a u l t to le rance of a network, func t iona l a v a i l a b i l i t y is proposed as t h e probabi l i ty of being a b l e t o communicate among t h e surv iv ing NCP ' s i f f a u l t s occur i n t h e network. Functional a v a i l a b i l i t y of the proposed loop network is compared with redundant loop networks. It is shown t h a t t h e s u p e r i o r i t y of func t iona l a v a i l a b i l i t y of the proposed network becomes greater as t h e number of NCP's increases .

Highly reliable loop computer network system based on autonomous decentralization concept

A computer network, in the broad sense, is any system composed of one or more computers and terminals, communication transmission facilities, and specialized or general purpose hardware to facilitate the flow of data between terminals and/or processors. Its parts consist of communication devices, the host processors, the transmission lines and a set of rules, implemented in either hardware or software, to insure the orderly flow of traffic in the network.

Computer communication networks: the parts make up the whole

How do you interconnect a large, heterogeneous group of computers, batch terminals and conversational terminals to form a general purpose network of computing resources? What techniques and technologies can be applied to maximize throughput and minimize response times? Is major surgery on host processor operating systems really necessary to interface to a communications network?This paper will describe a packet switching data communications network under development at the National Security Agency for resource sharing and the future development of distributed processing and filing systems. Starting with an experimental three node loop, the network will consist of a hierarchy of interconnected loops or rings probably based on Bell System T carrier digital transmission technology.Also discussed will be the means of nodal connection to the loops, the configuration of a node, network protocol, security considerations and implications for the future.

Thomas E. Hassing

Papers

A loop network for general purpose data communications in a heterogeneous world