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.