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QUALITY COMMUNICATIONS: A TOP NASA PRIORITY
eeting the exacting requirements of America's aerospace program places demands on NASA's communications resources. Thousands of government employees, contractors, subcontractors, researchers, and scientists are
engaged in hundreds of diverse projects at facilities around the country. All have a critical need for fast, accurate communications.
The job is complex. Some estimates indicate that NASA communications requirementsmay well double in the foreseeable future.
That's why NASA has taken a lead role in developing the Program Support Communications (PSC) Network. Managed by the Marshall Space Flight Center's Communications Office, the PSC Network will enhance NASA research, development, test, and mission support activities by taking advantage of the dramatic telecommunications breakthroughs of the past few years. Breakthroughs that affect everything from the way computers communicate with one another across the country to the way we make phone calls across the hall. With these improved telecommunications possibilities, the PSC Network achieves a quantum step in NASA's pursuit of improved quality and productivity.
NASA communications services provided by the PSC Network include longdistance telephone service, packet and circuit switched data communications, facsimile and electronic mail, voice and video teleconferencing, and a new computer network service to provide access to NASA's Class VI Supercomputer centers.
The PSC Network is a versatile, digital network employing both terrestrial and satellite transmission facilities which will interconnect 16 NASA locations. The system provides NASA with (1) improved quality and variety of communications services; (2) rapid response to new or changed network services and requirements; (3) advanced information exchange capabilities to reduce or avoid other NASA direct costs; (4) better traffic data for future planning; and (5) improved maintenance of network configurations.
A NETWORK DESIGNED TO MEET NASA's SPECIAL GOALS SC Network helps NASA meet two critical goals:
.To provide the environment and facilities needed to perform the highest quality work in research, development, rrllssions, and operations;
• To establish NASA as a leader in the development and application of advanced technology and management practices that significantly increase Agency and national productivity .
With these two goals in mind, NASA set an objective of establishing a Program Support Communications Network by FY 1986. One that will supply the voice, video, and data transfer resources NASA requires. The first step in the design of the PSC Network was to establish system objectives related to NASA's environment. Because NASA must operate within scientific, business, and Government communities simultaneously, its telecommunications resources cannot be isolated or private. These resources must cooperate with an increasing range of public and private telecommunications services.
Similarly, traffic requirements are a major consideration in network design. Changes in volume, speed, type, and location are all considered. A properly designed network can expand or contract while keeping cost and performance in balance. Based on an extensive requirement definition and design phase, the PSC Network is designed to meet or exceed all NASA PSC objectives:
Connectivity. Interconnection of many users, terminal types and protocols, and local facilities was a primary goal. The PSC Network was designed for a multi-origin, multi-destination environment. Accessibility. The network supports the user's ability to easily establish communication paths and permits the user to locate and easily establish an end-to-end link with needed information sources, services, or people. Security. Systems with open connectivity and easy user access generally are susceptible to intrusion. The PSC Network uses both physical and software means to limit network and resource access to authorized individuals. It also prevents intruders from monitoring the network. Encryption of transmissions among network gateways using the National Bureau of Standards Data Encryption Standard (DES) will further prevent interpretation of m essages communicated within the PSC Network. Reliability. Missions depend on automation, information processing, and intersystem communication in the scientific and business communities. That's why the reliability of telecommunications systems has become increasingly important. As a result, reliability concerns guided the entire design process. Maintainability. Problem prevention was emphasized throughout the design along with quick problem detection and correction without service interruption. Flexibility. Networks must change and grow to meet new user demands and traffic patterns. They must incorporate new technology and interface with
changing terminal equipment. And they must use new services from various suppliers. In today's environment, no single vendor has all the resources or products to satisfy all NASA telecommunication requirements. That's why it was critical to develop an overall system architecture which would allow various products to work together to meet the Agency's farreaching objectives. Cost and Performance. In an optimum system design, performance must be balanced effectively against cost. The system must be capable of satisfying peak demand, yet avoid the exorbitant cost of sitting idle during off-peak periods. Manageability. Manageability relates to network operation and control. Network designers and operators must be able to change and control the system under various abnormal traffic conditions and maintain the network for optimal performance and efficiency. This includes the ability to diagnose problems anywhere in the network.
NASA NETWORK LOCATIONS NASA Headquarters Ames Research Center Dryden Flight Research
Facility Goddard Space Flight
Center Jet Propulsion Laboratory Johnson Space Center Kennedy Space Center Langley Research Center Lewis Research Center MaTshall Space Flight
Center Michoud Assembly Facility National Space
Technology Laboratories Slidell Computer Complex Wallops Flight Facility Western Launch Operatiolls White Sands Test Facility
NETWORK ARCIDTECTURE: THE BACKBONE CONCEPT he need to efficiently respond to changing requirements led to the choice of a "layered" architecture. In a layered network, functions are allocated to defined layers and are usually implemented in separate modules.
The modules have well-defined interlaces. 1bis architectural approach allows users to extract any module and then change or improve it without affecting other modules as long as the interface requirements are met.
TIlls also means that there can be a clear demarcation between the network and other telecommunications systems. Each NASA center can manage, change, and operate its local administrative telecommunications systems without being constrained by requirements to interface with the PSC Network. Likewise, the PSC Network is not dependent on any condition within a local center's network. Each can be managed and operated with a clean interface between them.
The design for the PSC Network is based upon a foundation of circuitry, hardware, and software called the Backbone Network. Using fully encrypted terrestrial and satellite digital trunks controlled by sophisticated
switching equipment, this design replaces the expensive dedicated networks previously used to support individual applications. The result is a completely digital, virtual network enabling the various user services to share a common set of diverse communication facilities.
The use of diverse transmission facilities supports two important characteristics fundamental to the flexibility and performance of the Backbone Network. The first is the inherent reliability afforded by having individual functions supported by separate transmission paths - no single point failure can stop all network operations.
The second is the flexibility provided by the network control capabilities and the diverse transmission facilities. Network services with specific characteristics can be routed across transmission facilities best suited to the job. For example, the broadcasting of video teleconferencing is particulary suited for transmission over satellite links, whereas communications for interactive computing are far more effectively served via terrestrial links .
By sharing the versatile facilities of the Backbone Network in this fashion, NASA realizes greater cost efficiency and performance than would be possible using dedicated networks.
In addition, the Backbone concept encompasses shared use of network resources, provides high reliability, and maximizes efficient network utilization. Finally, the network itself can be used to provide visibility and control. Traffic, status, and alarm data from the network's operational modules are integrated into a common management and control system.
Local System Interface The PSC Network is prov
ing itself capable of supporting a totally integrated communications system for individual facilities. Centers throughout NASA are now upgrading their local communications systems, using standard interfaces between the Backbone Network and the local system. The work under way at Marshall Space Flight Center is typical.
The Center's new integrated Telecommunications System will provide local service through modem, digital PABX's and terminal equipment, integrated by full digital interfaces with the total NASA network. The system consists of a central switching system, universal wiring, and telephone equipment. Together with the PSC Network, the system providcs local and long-distance telephone and data service through a fully digital communications system.
Now employees can work more productively thanks to advanced services such as touch tone dialing, single-digit redialing of the last number dialed, abbreviated dialing of frequently used numbers, call transfers without operator assistance, user-arranged conference calls, and call forwarding under busy or "no answer" conditions.
VOICE Long-Distance Telephone Service
For NASA users who need higher quality service and more capabilities, the PSC Network upgrades the current facilities of the Federal Telecommunications System (FTS) used by the Federal Government for most long-clistance calls. The enhanced capabilities will route all FTS calls to a circuit network processor where they are screened. Calls intended for NASA gateway locations are routed into the PSC Backbone Network. All others are routed to existing FTS access lines. The entire procedure is completely transparent to the NASA user, who will dial the same FTS number as before.
The new system provides a "no-loss" long-distance system that dramatically cuts noise. Thanks to enhanced technology, users avoid annoying echoes and hear a much cleaner and clearer signal. Typically, calls will be completed faster, and callers will seldom receive busy signals because of blocks or delays in the network.
Teleconferencing Through the PSC Net
work, NASA has enhanced its existing voice teleconferencing system with new teleconferencing bridges, controls, and room equipment. The new room equipment is much easier to install, move, or change. Employing terrestrially routed, virtual circuits, the PSC Network gives local operators complete control and allows direct dial for two-party teleconferences. And it makes operation and room reconfigurations simpler.
These enhancements make the system easier to use and provide better voice quality. Users also enjoy much greater capacity. Up to 390 different callers can tie in at once! And because the system is so efficient, it will still cost less than using the old system.
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For maximum efficiency, the PSC Network offers two types of data service: packet switched and circuit switched.
The packet switched data system extends the existing NASA Packet Switching System. Designed to serve synchronous or asynchronous interactive users at transmission speeds of 9600 bps or less, it employs new packet assembler-disassemblers (PADS) for greater control and flexibility. These devices allow the system to support more protocols, while making the system easier to use and more secure.
When high-capacity synchronous data paths at 56 kbps are needed - typically for machine-to-machine traffic - users can dial up the circuit switched data service. A breakthrough in speed for systems supplying data communications at the PC level and above, the network can transfer data 40 times faster than comparable asynchronous systems. PSC represents the first application of this size for this exciting new technology. And it is fully compatible with AT&T s ACCUNET Switched 56 Service, now being implemented in 70 U.S. cities.
But NASA's 56 kbps dialup service offers other advantages as well. Because data circuits are not dedicated, they are not as vulnerable to outage and inefficient use. Also, Backbone circuit switching is independent of protocol, so
it can accommodate many different terminal devices and technology changes. Compared to other telecommunications systems, which can require months of lead time to install a dedicated line the PSC Network gives NASA users immediate dial-up access. Computer Network Service
The Computer Network Subsystem handles highspeed data transfer among computers - including NASA's Class VI supercomputers - while providing 1.544 Mbps switched service and packet service from the Backbone.
With this new capability, NASA will use its computers much more productively on a number of critical projects.
Designed for bulk data transfers among mainframes at four individual NASA facilities, the service relies on PSC's Data Buffer Interface Units at each site. These devices perform store-andforward functions and contain the software that provides control and interface capability throughout the Computer Network Subsystem.
MESSAGE Facsimile
Facsimile service uses the Backbone Network in the same manner as the voice service. All NASA facilities have received the latest digital facsimile transceivers, featuring universal compatibility and significantly greater speed, to replace their existing equipment. These transceivers, which meet CCITT Group ill standards for transmission speed and copy resolution, have achieved remarkable quality, efficiency, and pr?ductivity gains. TransllllsslOn speeds have jumped from 10 pages per hour to 180 per hour. Cost has dropped from $3.50 per page to $ .19 per page. And resolution has improved from 20 lines per inch to 400 lines per inch.
What's more, the system offers the first central storeand-forward feature ever available for facsimile transmission. At each center, users can now send a document to all other NASA facilities with only one transmission! Already, it is creating a tremendous productivity boost. And because it can store documents until lines are free, there
is no more waiting on busy signals.
Separate facilities ~d equipment are also available for secure facsimile. And when standards have been set for 56-Kbps facsimile terminals, the network will supply the switc~g and. transmission functions WIthout significant modifications. Electronic Mail
Electronic mail has been a growth area at NAS.A. Because of its success ill improving operating efficiency, traffic levels have mushroomed.
The PSC Network supports NASA's existing electronic mail service and provides enhanced transmission among facilities. For now, it handles messages alone. But its capabilities are evolving to meet new standards and future interconnection requirements. As in every part of the PSC Network, flexibility supplies a critical advantage in cost-effectively dealing with changing needs and technical enhancements.
VIDEO ThePSC Network was
designed as a dynamic, growing system, one that looks ahead for importarIt new developments. Today, NASA is examining the value of videoconferencing in helping to carry out its mission.
Within the next year, PSC will include proven videoconferencing capabilities. Staff at various NASA locations will have color, fulImotion service coordinated by a control console at Marshall Space Flight Center. The system will support both two-party and multiparty video meetings. And its active video link can be changed from site to site when Marshall control console operators initiate the appropriate switching. For multi-party conferences, all stations can participate in a full audio link while viewing video from one room.
Because the system is so easy to use, meetings can be set up in minutes rather than hours. Even more important, operating costs will be significantly reduced.
NETWORK MANAGEMENT ASA's PSC Network is provided through a Marshall Space Flight Center contract with Boeing Computer Services. As the prime contractor, the company is integrating components from about 70 subcontractors and suppli
ers and is providing mission services to support operations, maintenance, and sustaining engineering. Crucial to the success of the mission is wide experience in Network Management, a unique form of systems engineering and integration which includes a variety of design, implementation, and operation support systems.
Network Management Control System
Network designers and operators can change and control the PSC network under different outage and abnormal traffic conditions. They also maintain the network for optimum performance and efficiency. The system itself contains built-in monitoring, measuring, status reporting, diagnostics, and remote testing.
A central network management processor (NMP) performs the control and data collection tasks needed to carry out these functions. Located at Marshall Space Flight Center's Network Control Center, the NMP is an IBM 4361 processor connected to all network equipment by a combination of microcomputers called Network Management Interface Processors and the Backbone packet network. Together, these components compile information on directory and access control, alarms and system status, billing data collection, and network con-
figuration. Although equipment is spread nationwide, the central NMP assures tighter security, ease of access for end-users, improved configuration control, and more productive network diagnostic ability.
Network Management Information System
The PSC project organization will employ a Network Management Control System and Network Management Information System for complete visibility concerning performance, progress, and results. This ensures that NASA availability and reliability goals are met or exceeded. Furthermore, the Network Management Information System will provide the basis for future systems planning and expansion. Integrated Comrrllmications for America's Space Program
Progressive use of the best in current technology. Expert system integration. hnprovements in personnel productivity and communication quality. The flexibility and vision to prepare for the future. These are the ingredients that are bringing the PSC Network online. And supplying the communications resources to support NASA's technological leadership into the 21st Century.