A programmable front-end processing interface to the Series 1100 system and its communication management interface (CMS 1100) is the DCAITelcon system. It com-prises the following components:
Distributed Communications Architecture
Distributed Communications Architecture (DCA) is a total system design plan for any communications network which includes computers, communications controllers, data links, and terminals.
DCA governs the design of communications systems for the existing Series 1100 systems as well as future SPERRY UNIVAC products. It is intended to provide the direction for all communications-oriented development for the next ten years and beyond.
The architecture coordinates the development of network related items such as:
• Host Interfaces
• Communications network controllers
• Communications network software
• Terminals
• Data communications links and protocols Universal Data Link Control
Universal Data Link Control (UDLC) is the fundamental building block for all data com-munications in the Distributed Comcom-munications Architecture. It encompasses presently known variations of ADCCP, HDLC, and SDLC. UDLC is equally applicable to transaction, interactive, and batch transmissions. The design also accommodates multi-mode terminals on the same data communications circuit.
Efficiency higher than that provided by existing procedures is accomplished by bit orientation of data and control fields. This technique assures minimum overhead for control format and allows code independence of data.
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The SPERRY UNIVAC Telcon System comprised of the Distributed Communications Processor series systems and the enhanced Telcon software system provide the system capabilities required to meet this need.
The SPERRY UNIVAC Telcon System is an intelligent communications system which implements Sperry Univac's Distributed Communications Architecture (DCA). DCA establishes a common compatible communications concept to unify all of Sperry Univac's data communications products. It encompasses many user network requirements, ranging from simple star networks of nonprogrammable terminals, through large networks of mixed terminal types and applications, up to fully distri-buted networks connecting multiple hosts.
DCA provides a network philosophy which integrates control into the network so that the network portion of the communications system does not rely on attached pro-cessors to keep it operational. Additionally, control is distributed among the network components,just as applications are distributed throughout the communications system, with similar advantages. Consequently, network control functions can be handled more efficiently, with greater network resilience, than if all control functions emanated from a single point.
The major Design Goals of the Telcon System are as follows:
• To implement Sperry Univac's Distributed Communications Architecture (DCA) incorporating the advantages of an architectural standard.
• To provide a common interface and communications functions for 1100 Series Systems, Series 90 Systems, and terminal products.
• To provide a network that accommodates digital and Public Data Network (PDN) carrier services.
• To provide a network capable of full operation independent of host system type but designed primarily to support Sperry Univac host and terminal systems.
• To provide host system offloading by performing communications functions heretofore performed by host systems.
• Distribution of network functions enabling line savings, improved response times, and improved availability.
• Redundancy capabilities that protect against classes of failure.
• Host system independence such that the Telcon System continues opera-tions during periods when an attached host system is not operating. It main-tains communications with, and continues to support terminals as well as other host systems which are operating independently of an unavailable host system.
• Fail-soft recovery to alleviate critical or absolute failure of the network due to errors or malfunctions.
• User interfaces such that user own code may be incorporated into the soft-ware to accommodate application programs, non-DCA hosts, networks, or
The following is a brief overview of the major products which are embraced by Distributed Communications Architecture and the Telcon System.
• Distributed Communications Processor/40 (DCP/40)
• Distributed Communications Processor/20 (DCP/20)
• Telcon Software System
Distributed Communications Processorl40
The DCP/40 is a powerful state of the art communications processor which employs advanced microprocessor technology. It consists of multiple processing elements and utilizes integrated circuit memory and large scale integration.
The DCP/40 can be configured as a front end processor to Series 1100 and Series 90 systems as well as a remote network processor. In conjunction with the Telcon operating system, the DCP/40 can be used as a part of simple or complex network systems. Because the components of the system are modular in nature, it is possible to configure price competitive systems which fit most user requirements.
The DCP/40 can be expanded to include up to 256 ports for full or half duplex communications lines, direct channel connections to peripheral subsystems and host processors.
The main storage of the DCP/40 can be expanded from a minimum of 512K bytes to a maximum of 3.5 million bytes. It includes automatic error correction for single bit errors, and detection of double bit errors.
The DCP/40 incorporates program and data protection logic as well as highly advanced ARM and instrumentation capabilities.
Distributed Communications Processorl20
The DCP/20 is a low cost member of the family of Sperry Univac Distributed Communi-cations Processors. The DCP/20, like the DCP/40, employs advanced microprocessor technology.
It consists of a single microprogrammed Arithmetic Logical Unit and utilizes inte-grated circuit memory and large scale integration.
The DCP/20, in conjunction with the Telcon Operating System, can be used in a vari-ety of network structures. Like the DCP/40, it can be used as a front-end processor or a remote processor on Series 1100.
The DCP/20 can be expanded to include 48 Line Modules. The Line Modules provide the hardware interface to communications lines, peripheral subsystems and host processors.
The main storage of the DCP/20 can be expanded from 256K bytes to a maximum of 512K bytes in 128K byte increments. The storage utilizes integrated circuit technology. It provides automatic correction of single bit errors and detection of double bit errors.
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capabilities that support DCA ARM requirements.
DCP Feature Comparison
DCP/20 DCP/40 Primary Mode
Communications Processors 1 1
Communications Multiplexer 1-2 lOP 1-16 lOP
Communications Line
Module Capacity* 48 FDX/HDX 256 FDX/HDX
Host Interfaces 1-4 1-16
Peri pheral Interfaces ** **
Local Storage Capacity 512K Bytes 3.5M Bytes
Local Storage 500 nsec Read 400 Read
Speed (nsec) 500 nsec Write 450 Write
*The multiline asynchronous line module provides support for four circuits.
* *Variable. The peripheral compliment depends upon space used by communications line adapters.
Telcon Network Software
The Telcon Network Control Software has been designed to facilitate the transport of data among the many cOrnputers and terminals of today's information processing systems.
Standard system software provides the capability to transport data in several modes between network users. It provides complete support for high speed applications such as Remote Job Entry. It also accommodates interactive processing and trans-action processing. Basic message routing is provided. User interfaces, scheduling and queueing routines are available to support complex switching applications. It facilitates Distributed Data Processing.
The system software provides complete control within the network, independent of the host processor. Its modularity and flexibility allows the communications processor to function as a front-end processor, nodal (switching) processor or remote concentrator.
Telcon System Highlights
Designed and developed in accordance with the SPERRY UNIVAC Distributed Com-munications Architecture, the Telcon System incorporates state-of-the-art concepts in communications and software technology.
The Telcon System offers a complete solution to all network requirements ranging from simple star (point to point) networks to the most complex hierarchical, ring and distributed networks. Further it offers a clear evolutionary growth path as network requirements expand.
The Telcon System offers a comprehensive repertoire of features and functions
processor and puts it in the network for maximum efficiency and effectiveness. Fur-ther, the functions are distributed throughout the network to achieve the optimum utilization of all components.
Network Availability and Resilience
To assure the highest reliability and availability, the Telcon System offers the follow-ing features:
• Redundant Configuration - The network support redundant hardware and communications circuit configurations. This assures continued operation even in the event of equipment failures.
• Host Independence - The network is self-sufficient and can continue to operate even if the central processor is unavailable. It can maintain communi-cations with, and continue to support terminals as well as other processors which are operating independently of the unavailable system.
• Diagnostics - The system provides both online and offline diagnostics for maintenance of the network processors and the attached terminals.
• Fail-soft Recovery - Hardware and software facilities are provided to help alleviate critical and absolute failure of the network due to minor subsystem errors. Recovery routines put the failed node back in operation as soon as possible after an outage.
Network Management
Extensive network control functions are available to provide the highest level of con-trol to network administration personnel. The configuration of the network can be modified dynamically to accommodate changing environments.
Network Independence
One of the most important features of the Telcon System is the ability to accommo-date processors, terminals and networks other than those designed under Distributed Communication Architecture. Many existing terminals will be supported by standard software. Other equipment an be connected to the Telcon System by means of a soft-ware "Adapt" module which meets standard interface specifications. This capability facilitates interconnection to public and private networks.