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National Bureau

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NBSIR 80-2154

The NBS Computer

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Institute for Computer

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NBSIR 80-2154

the NBS Computer

Networking Program

Systems and Network Architecture Division

Institute for Computer Sciences and Technology

National Bureau of Standards

Washington, D.C. 20234

Issued October 1980

U.S. Department of Commerce

Philip M. Klutznick, Secretary

Jordan J. Baruch. Assistant Secretary for Productivity, Technology, and Innovation

National Bureau of Standards

Ernest Ambler, Director
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THE NBS COMPUTER NETWORKING PROGRAM

Blanc, R. , J. Heafner, R. Rosenthal, and S. Watkins

Institute for Computer Sciences and Technology

National Bureau of Standards

ABSTRACT

This report provides a description of the NBS program

in computer networking. The description includes

activities in computer network protocol development

for large global networks, protocol development and

measurement research for local area computer networks,

and protocol and format development for computer

based office systems. These efforts include the

development of standards and the performance of the

necessary research to support that standards development.

Descriptions of the specific products being developed

are also included.

Key words: Computer based office systems; computer

networking; interfaces; local area networks; measurement

techniques; protocols; and standards.

1
TABLE OF CONTENTS

Page

1. INTRODUCTION 1

1 . 1 Background 1

1.2 Program Structure 2

1.3 Organization 3

2. COMPUTER NETWORK PROTOCOLS 4

2.1 High Level Computer Network Protocol Standards 4

2.2 Protocol Research and Development 6

2.2.1 Protocol Design and Specification

Research 6

2.2.2 ICST Protocol Laboratory for Research

and Development 7

2.3 Additional Activities Supporting the

Development of Network Protocols 7

2.3.1 Impact of Satellite Communications . . 8

2.3.2 Impact of Security Considerations . . 8

2.3.3 The Impact of Tariff Structures ... 8

2.3.4 Management Protocols 8

2.3.5 Guidance on the Use of Standard

Protocols 8

2.3.6 Distributed Data Protocols 9

3. COMPUTER BASED OFFICE SYSTEMS 10

3.1 Standards Program 10

3.2 Guidelines Development 11

3.3 Laboratory Facilities 11

3.4 Future Direction 12

: i
Page

4. LOCAL AREA NETWORKING 13

4.1 Standards 13

4.2 Selection Guidelines 13

4.3 Measurement 14

4.3.1 Measurement and Control Objectives . . 14

4.3.2 Approach 14

5. REQUESTS FOR ADDITIONAL INFORMATION 16

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THE NBS COMPUTER NETWORKING PROGRAM

1.0 INTRODUCTION

This document, prepared by the Systems and Network

Architecture Division of the National Bureau of Standards

(NBS), provides an overview of NBS' programs in high level

network protocols, computer based office systems and local

area networking. Products and their associated dates as

identified in this report are subject to change.

1.1 Background

In the United States, and in other countries, networking

technology for interconnecting a wide variety of computers,

terminals, and special purpose systems is rapidly evolving.

National and international public data networks are

developing and expanding. Special technologies for local

area networks are now available. Special purpose networks,

for computer based office systems and for laboratories, for

example, are also emerging. Almost all manufacturers of

computing systems are developing network architectures for

interconnecting their diverse systems and, in some cases,

for connecting to the systems of other manufacturers. All

of these networking technologies and network architectures

have incompatibilities which obstruct interconnection. Such

interconnection would permit users to exploit the full

potential of networks and distributed systems. These

technologies must be able to work together, not only on a local network to local network, or global network to global

network basis, but also across different network

technologies. It must be possible to transmit, and

therefore share information originating in an office

network, through a local network, through a global network

in any combination.

The need for standard protocols to enable systems to be

interconnected and to operate together is well recognized.

The high level of activity by the manufacturers to develop

network architectures, and to develop communications
Page 2

standards by the communication service providers attest to

this need. Likewise, within the Federal Government there is

a strong need to develop communications and higher level

protocol standards as well as standards to permit the

interchange of documents among computer based office

systems. In recognition of these critical needs, NBS has

been funded to develop such standards. This program is

being conducted in coordination with voluntary standards

activities, with the efforts of manufacturers of computing

equipment to develop network architectures, with the

providers of computer based office systems, and with

agencies of the Federal Government.

1.2 Program Structure

This report describes the computer networking programs of

the Systems and Network Architecture Division which has

responsibility for the principal portion of the NBS computer

networking program. These programs fall into three major

areas; (1) high level computer network protocols , (2)

computer based office systems , and (3) local area computer

networks . The goal of these programs, collectively, is to

provide for distributed computing within the Federal

Government and to enable Government organizations to select

components of distributed systems based on cost and

performance without the constraints imposed by

incompatibilities

.

The computer network protocols program develops high-level

network protocols to enable the effective exchange of

information among computers as well as between terminals and

computers. The computer based office systems program

develops guidelines and standards to enable the effective

transfer of documents among systems through the electronic

interchange of information as well as through media

interchange. The local area networking program produces

standards and guidelines for the selection of local area

data networks, for the connection of devices to local area

networks, and for the interconnection of local area networks

to national and international global networks.

The overall NBS effort has three major components; (1)

developing standards and guidelines for the benefit of all

agencies within the Federal Government, (2) providing direct

assistance on a reimburseable basis to Federal agencies

requesting such assistance in technical problems related to

computer networking, and (3) conducting computer network

research in direct support of specific standards development

and agency assistance activities.
Page 3

1.3 Organization

Programmatically, the computer network program is one of the

major components of the computer network and systems

interface standards program being conducted by the Center

for Computer Systems Engineering of the Institute for

Computer Sciences and Technology (ICST) . ICST is one of

three major operating units (MOU's) of the National Bureau

of Standards. The development of standards and guidelines

pertaining to the high level computer network protocols,

computer based office systems, and local area networks is

carried out by the Systems and Network Architecture

Division. This work is complemented by the programs

conducted in the System Components Division that address the

development of base level communication protocols and

interface standards to enable the effective interconnection

of computer system components as well as the interoperation

of computer and data communications systems.

Sections 2 through 4 of this report describe the three

program areas in terms of standards development, advisory

services and research activities.
Page 4

2.0 COMPUTER NETWORK PROTOCOLS

Designing, implementing and maintaining a useful collection

of computer network protocol standards is a complex problem.

This complexity reflects: (1) the difficulty in determining

protocol features and then defining these features in an

unambiguous manner, (2) the need to assure conformance of

new protocol implementations with existing standards, and

(3) the requirement for future protocols to support more

sophisticated information processing requirements.

This section describes NBS activities directed toward

solving this problem.

2.1 High Level Computer Network Protocol Standards

The ICST program to develop high level computer network

protocol standards has three major objectives: (1) support

distributed computer networking, (2) enable the

interconnection of different components selected through

competitive procurements based on cost and performance, and

(3) provide agencies a means of avoiding unique and

therefore expensive solutions to networking problems.

The initial standards are those required to provide general

support to network users. They are intended to satisfy

Government requirements while deviating as little as

possible from existing protocols. The development of these

protocols will be carried out within an overall framework

established by the Reference Model of Open Systems

Interconnection* . These protocols are high level computer

network protocols that correspond to the transport control,

session control, presentation control and application

control layers of the ISO Reference Model. A major portion

of the work to develop the protocols and associated

technical products is being accomplished through

contracting. The initial standards and the projected

completion dates, in parentheses, are shown below.

*The International Organization for Standardization (ISO),

Reference Model for Open System Interconnection , working

document no. ISO/TC97/SC16 N227.
Page 5

1. Transport and Session Control Protocols — these

protocols encompass functions commonly referenced

in the transport control layer and session control

layer of the ISO Reference Model, (1981)

.

2. File Transfer and Data Presentation Protocols

these protocols, implemented at the application

layer and the presentation layer, provide a common

representation and access method to files, (1981).

3. Common Command Language Protocol — these commands

provide a common user interface applicable to data

transfer, remote job entry, and other network

operations, (1982).

4. Virtual Terminal Protocol — this protocol results

in a presentation layer protocol that will permit

terminals with different character isics to connect

to any network computer system, (1982)

.

5. Remote Job Entry Protocol — this protocol (s)

permits batch jobs to be initiated and executed

remotely in a network, (1983)

.

6. Network Interconnection Protocol — this protocol

permits the interconnecting of computer networks

through a gateway facility, (1983)

.

7. Unified Presentation Layer Protocol — this

protocol integrates other specific presentation

layer protocols to provide a uniform data

transformation capability, (1983)

.

8. Network Interprocess Communication Protocol — this

protocol facilitates initiation and control of

asynchronous processes on distributed computers,

(1984)

.

9. Distributed Data Protocols — this set of protocols

facilitates user access to distributed data in a networking environment, (1985)

.

As part of the development of these standards, NBS staff is

providing briefings to managers and technical experts in

Government and industry and has received information from

them on their networking activities and developments.
Page 6

2.2 Protocol Research And Development

In order to develop computer network protocol standards for

this dynamic technology it is necessary to perform a certain

amount of directed research and development. This section

describes NBS research and development efforts which support

the protocol standards program.

2.2.1 Protocol Design And Specification Research -

The ability to communicate using networks of heterogenous

computers requires computer network protocol standards. A

family of protocols, organized in a hierarchical

relationship, that together satisfy the requirements of a broad spectrum of applications, makes implementations easier

and provides greater compatibility. With the growing number

of different networks and diversity of uses, it is becoming

increasingly more difficult to define efficient protocols

that match applications needs effectively.

Among the problems of modern protocol design are the

following:

1. There are no agreed upon syntax and semantics for

expressing the service and functional capabilities

of a protocol. Hence, it is difficult for users

and designers to devise complex protocols, and

readily reach a common understanding of them.

2. There is no taxonomy of applications as they relate

to the requirements imposed on protocols. Nor is

there a viable methodology in constructing such a taxonomy.

3. There is no procedure for expressing the

quantitative and qualitative association of

application needs and protocol features.

4. Finally, there is no demonstratable technique for

selecting the optimal protocol set based upon

sufficiency of need and cost/performance.

Resolving these problems would simplify the design of

computer network protocol standards. In order to begin

answering these questions, NBS has a small research project

to construct a methodology for precisely defining the

service features provided by a protocol. Initial results

from this project have already been obtained. As this

methodology develops, it will become important in defining
Page 7

the precise collection of protocol standards being developed

by NBS.

2.2.2 ICST Protocol Laboratory For Research And Development -

To gain wide acceptance by Government organizations and to

promote compliance by manufacturers, it is necessary to

insure that the protocol implementations operate in

accordance with their design specifications and that

individual features perform at an acceptable level.

Furthermore, it is desirable to demonstrate and certify

implementations on vendors' systems.

NBS is developing a Protocol Laboratory for the purpose of

testing the correctness and performance of draft standard

protocols. The major benefits derived from the Protocol

Laboratory are to:

1. Ascertain that the protocols perform correctly and

according to their design specifications,

2. Determine the performance of the protocols to

improve algorithms implementing individual

features,

3. Permit alternate implementations of individual

protocol features to study relative performance,

4. Make possible accuracy and performance testing of

commercial implementations, and

5. Enable offloading studies that can decide the most

advantageous placement of protocol functions within

a network.

Initially the Laboratory will provide the capability to

simulate computer networks. Later a network emulator may be

added in order to accurately assess high-level protocol

behavior under realistic network throughput and congestion

conditions. The Laboratory will be coupled to one or more

public data networks connecting the Laboratory to NBS

contractors and other interested parties.

2.3 Additional Activities Supporting the Development of

Network Protocols

In addition to those activities already cited in this

section, NBS has initiated other efforts to support the

development of network protocols. These efforts will all
Page 8

result in either draft or final reports in calendar year

1981.

2.3.1 Impact of Satellite Communications

A study has been initiated which will result in an analysis

of the impact of satellite communications on network

protocol design. This analysis will factor in the impact of

high speed, long propagation delay communications on all

high levels protocols (levels 4, 5, 6 and 7 in the ISO

Reference Model) . Recommendations will be made on how

protocol design should reflect these considerations.

2.3.2 Impact of Security Considerations

The computer network protocol program is not attempting to

solve the network security problem, however, it is essential

that the protocols be specified in such a way so as not to

preclude computer security. A study will soon be initiated

to analyze the impact of security on the design of high

level protocols. This analysis will result in protocol

specifications that can support computer security as

security is needed in a particular environment.

2.3.3 The Impact of Tariff Structures

It is possible that changing tariff structures in the United

States and in other countries will have a significant impact

on the design of computer network protocols. It is

necessary that the protocols be specified in such a way to

maximize the benefits to the users under different tariff

structures. A study has been initiated to evaluate the

impact of current tariff structures on high level network

protocols and to analyze protocol features that should be

made dynamic in order to accomodate changing tariffs.

2.3.4 Management Protocols

ICST intends to initiate a program to identify and, as

appropriate, specify network management protocols. This

activity will closely parallel associated activities within

ISO and ANSI to develop such a set of management protocols.

2.3.5 Guidance on the Use of Standard Protocols

ICST intends to develop a set of guidance documents, the

first in 1981, to provide assistance in utilizing standard

protocols in different application and communication

environments. These guidance documents will assist users in

specifying protocols and in selecting the appropriate

features of individual protocols for different application

environments. In addition, examples will be given of

software specifications to interface the transport protocol

to different kinds of lower level technologies.
Page 9

2.3.6 Distributed Data Protocols

All of the protocol described so far (with the exception of

network interprocess conununication) require the user to deal

with a "network of computers", that is, the user must be

aware that many systems are connected to a network in order

to use those systems. Research has been initiated in

defining a set of distributed data protocols to locate,

structure and present data on behalf of the user without the

user having to deal with individual systems. These

protocols will use the services of the lower level protocols

described herein including the extension of the session

control protocol which is called the "network interprocess

communication protocol".
Page 10

3.0 COMPUTER BASED OFFICE SYSTEMS

The term "computer based office system" refers to

computer-based techniques applied to the information

processing requirements of office workers to help them do

their jobs more efficiently and effectively. These

techniques include automated data entry, text processing,

document formatting, document storage and retrieval, and

document distribution, both through media interchange and

data communications networks.

3.1 Standards Program

A number of standards are planned in the Computer Based

Office Systems Program. NBS is working with such voluntary

organizations such as ANSI and the International Federation

of Information Processing Societies (IFIPS) . NBS is also

meeting with vendors and Federal agencies to ensure that the

standards reflect the interests of the Government and are

compatible with industry trends. This program is intended

to foster cooperation and interaction so that the standards

may be developed efficiently and effectively.

A Message Interchange Format Standard is being developed for

issuance in 1981. It will apply to "electronic mail" or

messages exchanged among computer-based message systems.

This standard will permit interconnection, so that users on

one system will be able to send and receive messages to and

from users on other systems.

A Flexible Disk File Format Standard is scheduled for

issuance in 1982. It will establish common file formatting

and labeling conventions for flexible or "floppy" disks,

permitting them to be widely used as a medium of data

interchange between dissimilar systems.

A Text Editing Directives Standard is also scheduled for

issuance in 1982. It will establish a minimum common set of

user directives or commands for text editing systems or

services. This will ensure a minimum level of functionality

on the part of all text editors considered for Federal use,

as well as reduce the amount of retraining required when

operators switch from one editor to another.

A Text Formatting Directives Standard is scheduled for

issuance in 1984. It will provide a minimum common set of

user directives or commands for text formatting systems or

services. This will ensure a minimum common functionality

on the part of all text formatters considered for Federal

use, as well as reduce the amount of retraining required
Page 11

when operators switch from one formatter to another.

A Message Processing Directives Standard is also scheduled

for issuance in 1984. It will establish a common set of

user directives or commands for computer based message

systems. This will ensure a minimum common functionality on

the part of all computer based message systems considered

for Federal use, as well as reduce the amount of retraining

required when operators switch from one message system to

another

3.2 Guidelines Development

A document entitled Guidance on Requirements Analysis for

Office Systems has been issued in 1980. It addresses the

justification and evaluation criteria for the installation

of computer-based office equipment.

A FIPS Office Automation Glossary will be issued in 1981.

It will ensure the use of a common vocabulary among the

individuals involved with office automation, and will

provide a uniform basis for the standards development

program.

3.3 Laboratory Facilities

NBS operates an Office Systems Laboratory to support its

program in Computer-Based Office Systems. Included in the

laboratory are a number of modern text processing systems.

The Office Systems Laboratory shares facilities and space

with the Local Networking Laboratory. Nodes on NBSNET (a

local area network developed at NBS) connect laboratory

terminals to other on-campus computing resources, including

the variety of text processing software available in the

ICST Experimental Computing Facility. Special purpose I/O

equipment is also available for use in the Office Systems

Laboratory such as voice recognition (input) equipment and a voice synthesizer (output).
Page 12

3.4 Future Direction

Based on the responses to the draft message format standard

and interaction between NBS and others working in the area

of computer based message systems (CBMS), a number of

standards and developmental activities are being initiated.

A logical extension to the message format standard is a message presentation standard. This standard will address

the user interface to a CBMS with respect to a how a message

received by a CBMS is displayed to the user (e.g., the order

of presentation of the message fields).

There are a number of developmental activities with respect

to CBMS which NBS will be addressing in the timeframe of

1981 through 1985. Among these future activities are: an

architecture for CBMS, specification of message recipient

and originator identities (i.e., addressing), a message

prbtocol, and incorporation of multi-media messages into the

message format standard.
Page 13

4.0 LOCAL AREA NETWORKING

NBS has initiated a local area networking program with three

major components. The first component provides FIPS

standards and guidelines applicable to local network

installations in the Federal Government. The second

component provides agencies with technical assistance from

NBS in the selection and use of local area networking

hardware, protocols, and applications. The third component

is a research initiative in the design, development, and

implementation of local network performance measurement

techniques. These three program components provide the

framework to address three important local area data

networking issues: standards, selection, and measurement.

4.1 Standards

Local area network technology is relatively new. To

identify the need for standards in the Federal Government, a needs assessment is being performed. Preliminary results

indicate that over the next five years, the Federal

Government will procure upwards of 2000 local area networks.

NBS plans to complete this assessment of local area network

standards in 1980 and to develop a local area network

interface standard for the Federal Government by 1982. NBS

is participating in local area networking standards

activities in ANSI and the IEEE.

Recent activities within the IEEE local networking standards

group may make it possible to accelerate the local area

network interface standard effort. NBS is assisting this

effort through direct participation and through technical

development. In particular, NBS is generating a formal

description of the proposed link level protocol using the

formal description technique which has been applied to the

NBS transport protocol. In addition, NBS is analyzing a network interface sublayer required to map the requirements

of the NBS transport protocol to the local area network

protocol.

4.2 Selection Guidelines

The first product from the local area networking program is

a guideline on the selection of these networks. This

guideline will discuss the criteria by which Federal

agencies specify, evaluate, and select local area computer

networks based on applications. These guidelines will

enable Federal agencies to perform a step-by-step analysis

of their local computer networking requirements and to state

these in functional terms. This selection criteria

guideline will be available in 1981.
Page 14

4, 3 Measurement

The design and implementation of data communication

facilities includes instrumentation, measurement, and

control capabilities. To better understand how these

capabilities apply to new local networking technologies, NBS

has established a research program in the measurement and

control of local area networks. This program includes the

engineering of interfaces to local area networks, the

development of low level software routines to gather data

from these networks, and the development of analysis

routines to aggregate data and to produce reports for the

managers and engineers responsible for the performance and

maintenance of the local area network.

The research goal is to develop expertise in the measurement

and control of these networks and to apply this expertise to

existing and planned Government local networks.

4.3.1 Measurement and Control Objectives

There are five objectives of the NBS measurement and control

study. The first objective is to develop a local data

network measurement and control system capable of recording

and time tagging packets of data on the local area network.

In addition, this system must be capable of generating

controlled traffic loads. The second objective is to

perform experiments under controlled loading conditions.

From these experiments performance characteristics such as

utilization, throughput, delay, and stability can be

determined. The third objective is to study usage patterns

of local area data networks; of primary interest is the

data traffic to and from terminal nodes to major computing

resources in the local community, and the intra and inter

building traffic patterns. The fourth objective is to

validate and verify proposed local data network models. The

fifth objective is to evaluate the impact of host interfaces

and gateways on the performance of local data networks. In

this way the methods for interconnecting local networks to

other local networks and interconnecting local networks to

global networks will be analyzed.

4.3.2 Approach

The measurement and control center utilizes existing local

area data networks at NBS. These networks include NBSNET , a local area broadcast packet switched network designed and

implemented to support the scientists and engineers on the

NBS campus. This network employs a carrier sense multiple

access, collision detection protocol for sharing a common

coaxial cable among all active users. In addition a small

experimental CATV local area network, called the Mitrebus,

will be utilized to study the technical control of radio

frequency cable systems. The measurement and control center

complete with its traffic generator will enable ICST to
Page 15

perform controlled experiments in the local area networking

laboratory.
Page 16

5.0 REQUESTS FOR ADDITIONAL INFORMATION

The products described in this document take the form of

Federal Information Processing Standards and Guidelines. In

addition many intermediate results have been reported in NBS

Special Publications, NBS Interim Reports, contractor

reports to NBS, and papers published in trade and

professional journals. Organizations needing more

information or copies of any of the products or reports

should write to the NBS at the following address:

National Bureau of Standards

Systems & Network Architecture Division

Technology Building, Room B218

Washington, D.C, 20234
NBS-1 14A IREV. 8-76)

U.S. DEPT. OF COMM.

BIBLIOGRAPHIC DATA

SHEET

1. PUBLICATION OR REPORT NO.

4. TITLE AND SUBTITLE 5. Publication Date

The NBS Computer Networking Program Ofganization Code

7. AUTHOR(S)

Blanc, R., J. Heafner, R. Rosenthal, and S. Watkins

8. Performing Organ. Report No.

9. PERFORMING ORGANIZATION NAME AND ADDRESS

NATIONAL BUREAU OF STANDARDS

DEPARTMENT OF COMMERCE

WASHINGTON, DC 20234

11. Contract/Grant No.

12. SPONSORING ORGANIZATION NAME AND COMPLETE ADDRESS rsrreer, city. State, ZIP) 13. Type of Report & Period Covered

15. SUPPLEMENTARY NOTES

I I Document describes a computer program; SF-185, FIPS Software Summary, is attached.

16. ABSTRACT (A 200-word or teas factual summary of moat significant information. If document includes a significant bibliography or

literature survey, mention it here,)

This report provides a description of the NBS program in computer networking.

The description includes activities in computer network protocols for large

global networks, protocol interfaces, and measurement techniques for local area computer networks and work in computer based office systems. These

efforts include the development of standards and the performance of the necessary

research to support that standards development. Descriptions of the specific

products being worked on are also included.

17. KEY WORDS ("six to twelve entries; alphabetical order; capitalize only the first letter of the first key word unless a proper name

separated by semicolons)

Computer based office systems; computer networking; interfaces; local area networks; measurement techniques; protocols; and standards.

18. AVAILABILITY ^Unlimited

I I For Official Distribution. Do Not Release to NTIS

I 1 Order From Sup. of Doc., U.S. Government Printing Office, Washington, DC

20402, SD Stock No. SN003-003-

I I Order From National Technical Information Service (NTIS), Springfield, VA. 22161

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(THIS REPORT)

UNCLASSIFIED

20. SECURITY CLASS

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PRINTED PAGES

22. Price

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