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DEFENSE
DATA
COMMUNICATION
1982-03-29
CHRISTIAN
ROVSING
A/S
Page
#
*1 DEFENSE DATA COMMUNICATIONS
SYSTEMS DIVISION
CHRISTIAN ROVSING A/S
*1 P̲r̲e̲f̲a̲c̲e̲
*3 This is your copy of *2 D̲e̲f̲e̲n̲s̲e̲ ̲D̲a̲t̲a̲ ̲C̲o̲m̲m̲u̲n̲i̲c̲a̲t̲i̲o̲n̲s̲.
The publication's aim is to describe concepts of modern
Defense Data Communications and present a number of
product realizations and programs of the Systems Division
of Christian Rovsing A/S.
Christian Rovsing A/S have been active within data
communication since their founding in 1963. The specialized
field of Defense Data Processing and Communication
was entered in the mid-seventies and the company has
since dedicated a major portion of its resources to
the design and implementation of data communication
solutions to both civil and military requirements.
Christian Rovsing A/S serve market needs ranging from
systems analysis and design to installation and training,
including post-delivery maintenance and field support.
This places the Systems Division of Christian Rovsing
A/S in a unique position to provide every assistance
in solving your application requirements.
*1 T̲a̲b̲l̲e̲ ̲o̲f̲ ̲C̲o̲n̲t̲e̲n̲t̲s̲
P̲r̲e̲f̲a̲c̲e̲
*1 I Defense Data Communications Overview
1. Introduction
2. Interoperability
3. System Security
4. Elements of Defense Data Communication Systems.
*1 II F̲u̲n̲c̲t̲i̲o̲n̲a̲l̲ ̲E̲l̲e̲m̲e̲n̲t̲s̲
1. Overview
2. Networks - Strategic and Tactical
3. Message Processing and Electronic Mail
4. Local Area Networks
5. Secure Gateways
6. Data Presentation - Viewdata
*1 III D̲e̲f̲e̲n̲s̲e̲ ̲D̲a̲t̲a̲ ̲C̲o̲m̲m̲u̲n̲i̲c̲a̲t̲i̲o̲n̲ ̲E̲n̲g̲a̲g̲e̲m̲e̲n̲t̲ ̲a̲t̲
C̲h̲r̲i̲s̲t̲i̲a̲n̲ ̲R̲o̲v̲s̲i̲n̲g̲ ̲A̲/̲S̲
CASE A: Message Processing - CAMPS
CASE B: National Strategic Network - FIKS
CASE C: Tactical CCIS System Upgrade -
HAWK Converter
CASE D: Strategic CCIS - VIDEOTEX
CASE E: Tactical CCIS - TOSCA
CASE F: Strategic Network - NICS-TARE
CASE G: Message Switching - CRISP
*1 IV C̲h̲r̲i̲s̲t̲i̲a̲n̲ ̲R̲o̲v̲s̲i̲n̲g̲ ̲A̲/̲S̲ ̲C̲o̲m̲p̲a̲n̲y̲ ̲P̲r̲o̲f̲i̲l̲e̲
1. Introduction
2. Company History
3. Company Organization
4. The Systems Division
*1 V P̲r̲o̲j̲e̲c̲t̲ ̲I̲m̲p̲l̲e̲m̲e̲n̲t̲a̲t̲i̲o̲n̲ ̲a̲t̲
C̲h̲r̲i̲s̲t̲i̲a̲n̲ ̲R̲o̲v̲s̲i̲n̲g̲ ̲A̲/̲S̲
1. Overall Project Approach
2. Project Implementation Procedures
3. Management and Program Control
4. System Engineering
5. Quality Assurance
*1 VI L̲o̲g̲i̲s̲t̲i̲c̲s̲ ̲S̲u̲p̲p̲o̲r̲t̲
1. Introduction
2. Organization
3. Installation
4. Maintenance
5. Training and Documentation
*1 I̲ ̲ ̲D̲e̲f̲e̲n̲s̲e̲ ̲D̲a̲t̲a̲ ̲C̲o̲m̲m̲u̲n̲i̲c̲a̲t̲i̲o̲n̲s̲
*1 O̲v̲e̲r̲v̲i̲e̲w̲
*1 I Defense Data Communications Overview
*1 1. Introduction
During the past several decades a multitude of defense
data communication and information systems - representing
different stages of technology and utilizing various
procedures - have been installed. The design of each
individual system has typically emphasized functionality,
operability, survivability, and security; and the overall
result has been manageable, self-contained systems
providing reasonable realms of authority to their users.
Therefore, a typical headquarters may contain several
complementary defense communication systems as illustrated
by Figure 1.
Even though commanders via their workstations have
access to each system, transfer of information between
systems must be based on manual or semi-automatic procedures.
It is not surprising, therefore, to find that new missions
establish demands beyond the capability of current
communication systems. The need for interoperability
between systems is evident, but implementation has
awaited the realization of adequate security.
Modern computer and communication technologies have
now advanced within the areas of multi-level security,
secure gateways, and standardization of communication
protocols to provide solutions and methods that facilitate
interoperability: an operator working at a terminal
attached to one system can now be provided with secure
access facilities through that terminal to other computer
systems without requiring manual conversion and transportation
of data between systems. Therefore, integration of
defense data communication and information systems
throughout the European Theatre of Operation can be
achieved as envisaged in Figure 2.
Christian Rovsing A/S have been engaged in the area
of data communication for almost two decades. Our activities
in defense data communications have increased significantly
during the past five years, and in 1980 a separate
division - The Systems Division - was established to
consolidate company resources dedicated to meeting
the exacting requirements of defense data communication.
The aim of this publication is to highlight the engagement
of Christian Rovsing A/S in the field of defense data
communication.
First, defense data communication systems - as they
are today - will be introduced, the essential concepts
of interoperability will then be defined, system security
discussed, and major elements of defense data communication
systems listed.
The principal functional elements of secure defense
data communication systems are described in chapter
II. Together, these building blocks form a cost-effective,
integrated defense data communication system.
Cases describing implemented defense data communication
systems are presented in Chapter III. Christian Rovsing
A/S have been involved in both equipment and system
aspects of these programs, and each case describes
objectives, benefits, functional elements, equipment,
and expandability with respect to the program.
Finally, a profile of Christian Rovsing A/S is presented.
The company's history, organization, and facilities
are presented to show that Christian Rovsing A/S has
the necessary resources to supply major Defense Communication
Systems. The methods developed for project implementation
are described which shows how resources are converted
to a system solution by means of procedures based on
extensive experience in major Defense Communication
Programs. And the Logistics Support provided by Christian
Rovsing A/S is presented. Our system products include
all necessary aspects of installation, maintenance/spares,
training, and documentation.
*3 Figure 1
*2 A Typical Headquarters
*3 Providing access to several
*3 complementary data communication systems
*3 Figure 2
*2 European Theatre Integration
*3 security ensured by Secure Gateways
*1 2. Concept of Interoperability
*3 A well-functioning defense system is crucically dependent
upon communication. Requirements to the spectrum of
information, speed, security, and integrity - to name
some of the most important aspects - must be met. As
there exist many data communication systems, with each
system ensuring services to limited environments -
allied, national, or civil systems, a solution to the
overall requirements of defense data communication
can only be provided by integration of the individual
systems, i.e. by interoperability.
The spectrum of information available is the range
of information available in each system; the transfer
of data between individual systems should take place
automatically, relieving operator burden and effecting
real-time communication.
Security between systems can be ensured by implementation
of secure gateways, or multilevel security facilities
at each system interface while security within a system
must be provided by the systems own multi-level security
facilities. Security can additionally be ensured by
manual/automatic data screening, vetting, and requirements
for release authorization.
Data integrity throughout an integrated defense data
communication system is effected during transmission
by means of code control. Human error can be minimized
by providing an effective man-machine-interface. Access
to any system can be facilitated by having within a
headquarters all workstations attached to all systems
via a local area network. In addition, a uniform set
of procedures and information/conversation mask displays
can be provided for each system, thus easing the burden
of operation.
Integration of different systems, i.e. achievement
of interoperability, is dependent upon system architecture.
System architecture describes the structure of a system
from the lowest level - carrier transmission - to the
highest level - workstation dialogue. The structural
layers utilized by our system architecture are given
in Figure 3.
The interface between each level is well defined, thus
simplifying expandability - e.g. addition of a new
application dialogue - and maintainability - e.g. upgrading
of presentation formats.
A system communicates with other systems according
to level dependent protocols. Two systems with the
same architecture, exchange data by means of the same
protocol at each level. Otherwise, a protocol conversion
is required for each level.
*3 Figure 3
*2 Inter-Network Architecture
*3 system communication by level dependent protocols
*1 3. System Security
*3 There need be no discussion that defense data communication
systems should meet stringent security requirements.
Security must be ensured at all levels, viz. physical
facilities, equipment, software, and operations. Examples
of significant security featues, implemented in Christian
Rovsing A/S's products, are:
*5 o Use of fiber optics - all visual display units,
printers and other similar peripherals can be connected
to a communications network by fiber optical cables
to preclude EMI problems
*5 o EMI shields - all equipment can be enclosed in
EMI shielded racks.
*5 o Signal filters - all cables carrying power or electrical
signals enter the system through signal filters
to prevent inadvertent dissemination of information.
*5 o Data protection by software/hardware - the Christian
Rovsing manufactured CR80/DAMOS provides a balanced
effort towards the achievement of secure systems,
providing access control mechanisms, integrity
protection and availability of service as an integral
part of CR80/DAMOS design.
*5 o Operational security - all user access to a system
is subjected to the following security mechanisms:
*5 o physical locks
*5 o authentication by means of log-on password and
security interogations
*5 o user, terminal, and channel clearance plays an
essential role in authorization check-out.
*1 4. Elements of Integrated Data Communication Systems
*3 The Systems Division of Christian Rovsing A/S provide
solutions to the requirements of a modern defense for
integrated data communication. This includes both the
design/implementation of total systems and integration
of systems. As a system house, we place emphasis on
overall design, reflected in the key areas of real-time
data transfer, security, integrity, availability, survivability,
and expandability.
Examples of the elements of communication systems with
which the Systems Division has significant experience
are:
*5 o Transport Network based on nodal switch processors.
*5 o Network Control Centers for overall network supervision
and control.
*5 o Concentrators for interface to user workstations.
*5 o Front End Processor between communication systems
and information processing systems.
*5 o Message Processing facilities for handling secure
electronic mail and formatted logistics and intelligence
information.
*5 o Secure gateways to facilitate transfer of data
between different categories of networks.
*1 II Functional Elements of Integrated
*1 Communication Systems
*1 II Functional Elements of Integrated Communication
Systems
*1 1. Products Overview
*3 The Systems Division of Christian Rovsing A/S have
relevant experience in virtually all phases of data
communication. Our involvement goes from individual
element design through interfacing to total system
responsibility. Figure 1 illustrates the involvement
of Christian Rovsing A/S in terms of product realization,
showing each product in relation to the layers of our
system architecture.
Of special interest with respect to defense data communication
systems are the following products:
*5 o Strategic and Tactical Transport Networks - FIKS
and NICS-TARE
*5 o Message Processing and Electronic Mail System -
CAMPS, FIKS
*5 o Local Area Network - TDX
*5 o Secure Gateway - CR Protocol Converter
*5 o View Data - VIDEOTEX.
*3 In the sections to follow, the five abovementioned
types of products are discussed. Further details of
product realization are given in section III, describing
objectives, benefits system functions, equipment, and
expandability of representative products
*3 Figure 1
*2 Product Realization
*3 structural relationship of elements
*3 of data communication systems
*1 2. Networks - Strategic and Tactical
*2 Features
*3 Modern strategic and tactical networks require the
following features:
*5 o Transmission of all types of information, text,
data and voice.
*5 o High flexibility to provide survivability and commonality.
*5 o Interoperability with other existing or planned
networks.
*5 o Security, privacy and availability of service
*3 Until recently, transmission of different types of
information have been accomplished by various means;
e.g. written telex messages by one type of network
and telephone communication via a different network.
The integration of different networks is now obviously
a major goal. As an example, NATO plans to complete
implementation of NICS - NATO Integrated Comuncation
System - in the 1990's.
Christian Rovsing A/S believes that such networks and
their interoperability are of vital importance for
the flow of information between national and international
organizations, and we have devoted many resources to
provide solutions for communication network implementations
tailored to meet all the required features listed above.
Figure 2 illustrates interoperability of National and
Allied Networks - strategic and Tactical. Descriptions
of different network types with which Christian Rovsing
A/S has significant experience are given in the next
section.
*3 Figure 2
*2 Network Interoperability
*3 connecting national and allied data communication *3 systems
*2 S̲y̲s̲t̲e̲m̲ ̲D̲e̲s̲c̲r̲i̲p̲t̲i̲o̲n̲
*3 The following describes different network types and
universal network concepts required by defense organizations
and offered by the Systems Division of Christian Rovsing
A/S.
*2 C̲i̲r̲c̲u̲i̲t̲ ̲S̲w̲i̲t̲c̲h̲i̲n̲g̲ *3 Systems meet the need for telephone
or voice transmission. Before actual transmission can
take place, the sending and receiving party have to
be connected by establishing a complete circuit connection
through different switching centers to provide a physical
connection between the two parties. This type of network
is the most suitable for lengthy exchange of information
between two parties, as is the case with telephone
conversation. For telex messages involving short circuit
holding times this connection scheme is uneconomical
because it will take too long to establish the connection,
and it is too expensive to keep connections permanently
if they are seldom used. Circuit switching uses, either
analog or digital coding schemes for transmission.
*2 M̲e̲s̲s̲a̲g̲e̲ ̲S̲w̲i̲t̲c̲h̲i̲n̲g̲ *3 Systems meet the need to transmit
messages in either manual or automatic systems. In
manual systems messages are punched on paper tape and
read into the transmission system, one by one, to be
transmitted from one switching center to the next.
At each switching center, a message is punched out
and interpreted by an operator to decide which outgoing
line should be used for the subsequent transmission.
This labor can be automated, so that a switching computer
performs all tasks. This type of message switching
system is called a store and forward system because
a complete message is received and stored for subsequent
transmission. The computer switching system performs
error detection and correction (EDC) on all messages
transmitted. Christian Rovsing A/S's System Division
has implemented message switching and communication
protocols in projects like CAMPS, FIKS and the NICS-TARE
Front-End.
*2 P̲a̲c̲k̲e̲t̲ ̲s̲w̲i̲t̲c̲h̲i̲n̲g̲ ̲*3 is part of the Christian Rovsing
A/S product line, with all elements to provide the
backbone data communication environment networks. This
modern data communication technology leads to simplified
switching centers and provides a very general and flexible
communication environment. Furthermore, this technique
lends itself to modern digital transmission technology.
Packet switching differs from store-and-forward in
two main areas. First, messages are partiotined into
a sequence of subunits called packets; these are transmitted
individually through the network. Second, packets are
retransmitted immediately at intermediate switching
centers. This leads not only to lower transfer times
through the network compared to the store-and-forward
technique but also to nodes with simpler control programs
and minimal requirements for memory, internal as well
as external.
The need for supporting interactive and bulk data in
an integrated network has resulted in two switching
techniques, virtual circuit and pure packet (datagram)
based techniques.
Datagram techniques require that all packets contain
self-sufficient routing information. whereas Virtual
circuit techniques provide a predetermined path through
the network - the Virtual circuit. The Datagram method
leads to higher overheads since each packet contains
routing information in addition to data. This technique
also runs into difficulties in dealing with long messages
which have to be split into multiple packets. Packets
are routed independently through the network possibly
using different routes. As a consequense, packets belonging
to the same message might arrive at the destination
out of sequence demanding that a resequencing should
take place. However, this technique is well suited
for bursty types of traffic, e.g. interactive and query/response.
Furthermore, this service is useful to a growing class
of subscribers who want to utilize only the basic transmission
service from a data communications network. These subscribers
either do not need an end-to-end protocol or prefer
to provide their own.
Virtual circuits established between users provide
an alternative technique well suited for bulk data
transfers, e.g. file transfers between host computers.
Packets of a message are routed along a predetermined
path - the virtual circuit - through the network. Several
users may simultaneously use the same physical circuit
for data transmission, hence the term virtual.
Another major aspect of communication is the concern
for international standardization of network types,
and standards are now available which provide these.
As an example CCITT has provided two essential standards
in this concept. The X.25 describes how user systems
shall interface to networks using a virtual circuit
concept in order to interconnect different networks,
e.g. public networks in different countries. CCITT
also provides the X75 standard which describes the
rules for gateways between different networks. The
protocols used in CAMPS for gateway capabilities to
other communication systems are based on these standards.
These standards are also used when interfacing between
tactical and strategic networks,i.e. interoperability
between the networks. This concept is essential because
tactical networks might use different schemes. For
example, within NATO's European countries, EUROGROUP
has established standards, i.e. EUROCOM to be followed
for future tactical networks; Other standards might
be found in non-European systems.
*1 3. Message Processing and Electronic Mail
*2 Introduction
*3 Advantages in computer technology have provided many
different services to the modern information based
society. Within the military community it is realized
how vital availability of extensive and up to date
information is for the decision making process in any
military operation. Success in warfare has always been
based on information reporting; that is why many resources
have been spent on observations and reporting of all
types of information. The automation functions pertaining
to message processing will yield many benefits when
implemented.
The concept of message processing and electronic mail
is based on the fact that many activities therein are
recurring and suited to automation. These activities
include the following features:
*5 - Drafting of messages with extensive correction
and restructuring
*5 - Guidance during information entry
*5 - Validation of message syntax, i.e. total structure,
substructure, length of lines, length of fields,
and type of fields.
*5 - Coordination of message contents and subsequent
correction before approval.
*5 - Schedule monitoring and reporting.
*5 - Distribution of messages within an organization.
*5 - Filing and retrieval of information.
*5 - Remote connection between users and/or systems.
*3 The Systems Division of Christian Rovsing A/S now offers
a range of message processing and electronic mail systems.
*1 System Description
*3 The introduction of modern visual display units, VDU's,
as replacements for typewriters or telex machines results
in immense improvement of the working situation for
message preparation personnel.
An intelligent VDU provides within itself many functions
which will assist the (individual person) in preparing
messages. It will display a format or layout of the
message to be prepared which contains much more guidance
information than earlier offered on paper forms.
As an example of versatile VDU terminals consider the
one implemented by Christian Rovsing A/S in CAMPS.
This terminal can store up to 20,000 characters locally
before transmitting to the host.
The format mask is stored within the system and can
be retrieved immediately by the user without leaving
his workstation. The system can store many more different
masks or formats than are pratical in a manual environment.
The entered information will be checked for syntax
errors instantaneously and it will be checked for semantic
errors before acceptance by the system. This minimizes
human checks required by message processing.
The types of syntactic checks include the quantity
of subset information or fields within the message,
in addition mandatory information can be forgotten.
The system will also ensure that information which
should be alphabetic or numerical will be entered as
such.
The semantic checks that can be performed are extensive.
Information which must belong to a larger known set
of information can be checked. For example, the name
of the recipient of a message can be validated as belonging
to the set of authorized names before final acceptance
of a message from the originator.
As soon as a messsage has been accepted by the system
from the drafters work station, it is processed automatically
without any delay. It has already been typed, so no
further entry by a typist is required, and by electronic
mail facilities it can be conveyed to the recipient(s)
INTENDED in real time.
Reception of messages is the other aspect of message
processing, whether the recipient is a human being
or a computer system. Traditionally people receive
messages from other people but now computer systems
can automate many of the time and manpower consuming
activities present in manual systems.
The electronic mail capabilities deliver a message
to the individual recipients workstation without any
time delay and without manual intervention by the communication
center.
In many military organizations complex delivery rules
are applied in order to identify final receivers for
either action or information, as a function of the
subject of the messages and the sensitivity of the
contents. These rules can be programmed into the message
processing system to avoid mistakes and time delays.
An example is given in the CAMPS description.
A modern message processing system will also assist
users in filing and retrieval of their messages. Many
different subject keywords can be used simultaneously
without necessitating duplication of physical files.
When messages are part of a larger information collection
scheme, modern computer systems can perform all the
processing pertained to message reception functions.
It can enforce timely reporting, where required, and
it can accumulate information received in several messages
to provide the decision maker with an overview. These
summaries might be provided on graphic terminals rather
than on alphanumeric displays.
The overall organization of human efforts is an essential
part of computer assisted message processing. Within
a military organization the ability to distinguish
the urgency of any subject is vital. When precedence
or urgency indicators are first introduced in messages,
the computer system can enforce the correct time sequencing
of all subsequent handling of these messages. For example
during preparation of a message, the user at the workstation
should immediately be informed of the arrival of any
urgent message at his terminal.
Further efficiency results from the use of modern workstations
which can be connected to more than one system and
assist the user in the overall performance of his work.
The VDU's implemented in CAMPS have 16 splits, i.e.
16 windows to the terminals memory space. These splits
could, in an expanded system, be used for simultaneous
communication with different systems.
One of the aspects of message processing, introduced
above, is the gradual transition towards a paperless
society. This makes many demands on computer security
in a military organization. For example the computer
system checks who has access to any stored information,
and it logs all events for later investigation, if
required. On the other hand an advantage is that it
minimizes the need for paper copies and hence it diminishes
the risk of security leaks.
The results of electronic mail implementation within
the military community are very promising. Electronic
mail capabilities of modern data communication systems
are used to convey messages from one place to one or
several other places without delays due to human intervention.
This capability is now so fast that conference systems
can be set up, providing immediate response to any
message. Pseudo meetings can now be held with participating
members situated at geographically distant locations.
Sitting at their respective workstations, they can
prepare information which will be immediately displayed
at all the other members' workstations. Answers can
be entered by the other members and the dialogue between
two or more members continues as long as required.
To really understand the implication of electronic
mail implementation it might be illustrative to imagine
that anything which can be coded in numbers can be
transmitted from one place to another. Examples include
pictures like radar display data, maps, drawings, fingerprints
or voice in digitized formats. All these different
types of information can be transported over the same
transmission medium, giving greater flexibility and
survivability, both of which are vital in a military
environment.
The electronic mail capability can also provide the
user at his workstation with remote access to computer
systems. In the military environment, the aspect of
remote access can provide the tactical user at the
front access to a computer placed far behind the lines.
More specialized or dedicated computers can also be
accessed from remote locations. Systems which contain
spare part inventories can be accessed without human
interaction. Handbooks of any kind, dictionaries or
even computers capable of human language translation
could be provided as services to users, and only one
universal workstation is required.
Expert systems, which apply artificial intelligence,
can be of great importance in the military environment.
The necessity of the presence of many experts can now
be minimized. An example known from the commercial
industry is medical diagnosis by computer, aiding a
non-medical expert.
Maintenance and repair of all kinds of equipment, including
computer equipment, can benefit from electronic mail
connections to expert systems.
The implications of introduction of computerized message
processing and electronic mail functions are farreaching
and hold many promises of immediately available benefits.
*1 4. Local Area Networks
*2 Features
A local area network provides a common and economical
medium for interconnecting different terminal types
to one or more systems. Essential features are to:
*5 o Provide flexibility in terminal placement within
a building and give easy relocation capabilities.
*5 o Provide access to several dedicated computers within
the same or different local area networks from
the same terminal.
*5 o Avoid nummerous point to point connection wires
between one computer and several terminals.
*3 The System Division of Christian Rovsing A/S can install
local area networks tailored to your specific needs.
*1 System Description
*3 Instead of establishing costly multiple connections
between a computer and its terminals, modern technology
provides the capability to equip all rooms in a building
or a local area, like a ship with a common transmission
media outlet. A single coaxial cable, can be installed
in a building, going from room to room in the same
fashion as power outlets are provided in all rooms.
This can be done at building construction time or later
as a one time investment.
Once installed a local area network provides great
flexibility in actual placement of terminals. The terminals
can be moved freely and connected to the network via
the outlet placed in each room. No relocation costs
are involved.
The local area network allows the connection of several
different types of terminal equipment. A small microprocessor
based terminal adaptor interfaces any old type of terminal
to the communication scheme used in modern terminals
and to the proper network.
All terminals and computers attached to the same network
can exchange information, i.e. a local area network
can provide an electronic mail facility within a building
or small company.
Any computer attached to the network can be reached
by any terminal. For example, a person who works partly
with a text processing system, partly prepares and
sends telexes, and partly does data entry for an accounting
system, can use the same terminal for all three applications
even if they are placed on three different computers,
as long as the computers are attached to the same local
area network.
If one of the computers attached to the network acts
as a gateway to long haul networks, then any terminal
user has access to all the services provided through
the long haul network.
The types of terminals that can be hooked up to a local
area network are not only human work-stations, but
any type of automatic sensing device which might report
its data through a local area network. Examples are
fire alarms, burglar alarms, equipment checkout devices
installed in local areas, buildings, airplanes, ships
etc. (Not all of these examples are unique to military
applications.
The ease of installation has been achieved by applying
a single, common transmission line throughout the area.
For relability reasons this transmission media might
be dualized to provide a back-up capability.
The concept of local area network is essential in achieving
interoperability throughout the information processing
sphere. It provides the common and overall interface
from the end user, human or not, to all types of destinations,
system or human, in an economical fashion. A local
area network is illustrated in Figure 4.
*3 Figure 4
*2 Local Area Network
*1 5. Secure Gateways
*2 Introduction
Modern integrated Command Control and Communication
Information Systems (C…0e…3…0f…I) require a secure and controlled
exchange of information between information processing
systems, networks, and work station. The exchange often
has to take place over inter-system boundaries that
do not match in terms of data formats, communication
protocols, and security levels.
A practical solution is to introduce a GATEWAY betweeen
the different systems. The features of a Secure Gateway
needs to be tailored to exact requirements.
*2 Features
*5 o Conversion of possible differences in the communication
protocols and data formats between the two inter-linked
systems.
*5 o Screening and vetting of the transfered information
*5 o Validation of security procedures.
*5 o Physical isolation between the two systems.
*5 o Buffering of data during temporary close down or
the reconnection to either of the systems.
*5 o Initialising and starting up the connection between
the systems.
*1 System Description
*3 Christian Rovsing A/S have in recent years implemented
many systems that act as gateways between computer
systems, front ends between computer systems and networks,
and concentrators for terminals. The systems have been
based on the company's CR80 minicomputer and the (MP)…0e…2…0f…
- MultiPurpose-MultiProcessor.
Typical examples of Gateway features are:
*5 o a gateway that acts as a transparent system passing
on the data immediately upon arrival and without
storing the data internally in the gateway. This
type of gateway serves typically as a converter
between two systems using different communications
protocols.
*5 o a gateway that acts as a screening station which
validates all traffic between two systems, and
at the same time performs necessary protocol and
format conversion. The validation may be performed
either automatically by comparison with prestored
approved formats, or manually using a man-in-the-loop
type procedure.
*3 The first type of gateway may typically be a simple
microprocessor system that does not need to take responsibility
for continuity in the traffic stream since this task
is handled by the interconnected systems.
The second type of gateway will typically need to store
the information in the gateway for the period required
for the converter to take over responsibility for the
information during the transfer and perform normal
acknowledgements to the two inter-linked systems.
The structure of a typical gateway to be used for transfer
of message traffic is shown in Figure 5. The software
is structured in accordance with the protocol levels
and consists of:
*5 o a level handling the data link control signals.
*5 o a level handling a link access protocol to ensure
an error free transfer of data frames from system
to gateway.
*5 o a level handling frame or packet assembly/disassembly.
This level ensures the correct assembly/disassembly
of messages into packets or frames. In a system
with different levels of precedence for message
traffic, level 3 may also facilitate multiplexing
of data frames from different messages accross
the link. This means that a low priority message
in
*5 process of being transferred may be interrupted
by a higher priority message. After transfer of
that message, the transfer of the lower priority
message is resumed from where it was interrupted.
*5 o a level for traffic handling; this level ensures
that messages are transferred in accordance with
precedence and security rules. It further ensures
that no messages are lost on the communication
line and has built-in procedures to handle recovery
from transmission errors.
*5 o a level that provides all required format conversion
due to differences in header information, address
information or presentation formats. It, further,
emulates differences in service and controls messages
accross the interface. In case screening of the
message is required, this level would also include
a message analysis facility and/or an interface
to a visual display unit (VDU).
*3 Figure 5
*2 Secure Gateway
*3 showing the functional layout
*1 6. Viewdata
*3 Viewdata is a facility for retrieving information from
computer data bases. The information is stored in "pages"
in the Viewdata system or may optionally be retrieved
from external data bases.
Viewdata adds, to a data processing environment, the
capability of using low-cost and standardized terminals
to interact with different data bases in a user-oriented
way. It can be implemented as part of an Electronic
Mail Service.
Viewdata offers the following capabilities:
*5 o Retrieval of Viewdata images from a database
*5 o Generation/modification of Viewdata images
*5 o Maintenance of user catalogue
*5 o Provision for generation of users in user groups
*5 o Maintenance of password
*5 o Message service
*5 o Generation of primary keywords
*3 A viewdata database supports three user access methods:
*5 o hierarchical search
*5 o direct page selection
*5 o selection by keyword
*3 Thus, Viewdata can provide user-friendly data presentation
displays in connection with a database.
Christian Rovsing A/S produces a Viewdata System -
VIDEOTEX - which is described in section III.
*1 III Defense Data Communication
*1 Engagement at Christian Rovsing A/S
*1 A. Message Processing - CAMPS
*1 A. Message Processing C A M P S
*1 1.Objectives
*3 CAMPS is a Computer Aided Message Processing System
with the objective of providing significant improvements
in communication to both strategic and tactical NATO
operations. Areas which will experience considerable
improvements are:
*5 o time needed for preparation and reception of messages
is reduced
*5 o manpower and cost are reduced
*5 o message handling procedure commonality throughout
NATO is increased
*5 o interoperability with other communication systems
is increased
*5 o required levels of security is achieved with less
effort
*5 o availability and accessibility of information is
increased
*5 o errors and misunderstandings are reduced
*5 o handling priorities are respedted
*3 Figure 1 shows the CAMPS operational environment.
The benefits resulting from the operation of CAMPS
are discussed in more detail in the next section.
*1 2.Benefits
*3 Manual message preparation is a slow and time consuming
process. A handwritten draft is first distributed manually
to other staff officers for coordination. These officers
then read the message perhaps making suggestions for
improvement. The draft-message may have to be retyped
one or more times. Before being finally submitted to
and individual with release authority, who signs off
and pass it to the communication center.Before transmission
a communication expert must ensure that the message
is in accordance with the ACP127 format used by NATO,
giving:
*5 o recipient for action
*5 o recipients official identification
*3 Figure 1
*2 CAMPS OPERATIONS ENVIRONMENT
*3 Tempest Certified Equipment in Background
*5 o information only recepients
*5 o urgency
*5 o security classification
*5 o other required attributes.
*3 Message preparation, as described above, can take from
one hour to several days in a manual environment: CAMPS
reduces preparation time by at least a factor of 10,
so that a message can be prepared, coordinated and
transmitted within a few minutes or at most within
an hour in the case of extensive coordination.
On reception, manual procedures first call for a clerk
to look up the messages Subject Indicator Code (SIC)
in a table of standard distribution list for incoming
messages. The received message is then photo-copied
to provide enough copies for both action and information
recipients. Finally, physical distribution takes place.
These manual procedures give the opportunity for many
errors and exposures. For example there is always the
risk that a message is not handled according to priority
so that a very urgent message might be delayed for
hours and too many, photo-copies give the possibility
of information falling into the wrong hands.
The time required for message reception, as described
above, is from 1 hour up to a whole day: CAMPS reduces
the time needed to carry out the reception process
by a factor of almost 100. Manpower and its related
costs are saved as CAMPS automatically analyses the
Subject Indicator Code and distributes the message
quickly and accurately to the appropriate terminal(s).
In addition CAMPS handles priorities automatically,
ensuring that urgent messages are expedited. All these
procedures are done without human intervention - typically
in only a few seconds. Additionally CAMPS ensures that
only authorized personnel have access to the delivery
terminals, through log-on procedures including user
identification and passwords.
The man-machine interface implemented in CAMPS is very
user-friendly and so easy to learn and use. The intelligent
visual display units and the computer system prompt
and assist the user; after only a few hours training
in preparation and coordination of messages he is capable
of taking full advantage of the CAMPS capabilities.…86…1
…02… …02… …02… …02…
This is in huge contrast to present demands for a highly
trained communications expert with a thorough knowledge
of ACP127 and procedural format requirements. CAMPS
yield great savings in cost and manpower.
Availability of information is enhanced by the filing
system of CAMPS, which is fully automatic. Without
moving from his workstation, a user can search the
CAMPS files for historical data - all messages sent
and received during the previous 30 days are retained.
Data needed for preparing new messages or data needed
for correct quotation can be retrieved via CAMPS. The
user-friendly retrieval system includes multiple search
keys. Users do not need to have exact message identification
to retrieve the message; a time window indicating when
the message was first filed - along with other optional
parameters - will narrow down the field, CAMPS will
then display a catalogue of all messages satisfying
the given parameters from which the user may choose
the specific message he resuires.
CAMPS provides message handling commonality throughout
NATO. This ensures that messages prepared at any CAMP
equipped headquarters will be interpreted correctly
at any other CAMP equipped headquarters. This will
save manpower and remove possible sources of error
and misunderstanding.
CAMPS ensures interoperability throughout NATO since
other communication systems can be interfaced via CAMPS.
In addition CAMPS' features are available as improvements
to these systems.
Aspects of security are accommodated to a very highdegree
in CAMPS. Security features are implemented in all
sub-systems within CAMPS, both hardware and software.
The modular construction of the CAMPS computer - with
individual peripheral microprocessors for each discs,
each terminal and each external line - ensures separation
of datastreams coming into and going out of CAMPS.
The design of system and application software ensures
that programs and data are completely separate in memory:
programs cannot be modified during execution; only
data can. In addition each program can only address
its own memory area. Address violation is detected,
and one program cannot alter another program's code/data
space.…86…1 …02… …02… …02… …02…
Users are approved to different levels of classification
and they can only access data up to their level of
classification, never at higher levels. The same philosophy
extends to the relationship between software and classified
information. Security interogation and warnings are
used throughout to ensure that the personnel and the
environment is double-checked before revealing high
classified information of a terminal.
The time required for message preparation and reception
is illustrated in Figure 2, which shown the improvements
resulting from the use of CAMPS.
*3 Figure 2
*2 TIME FOR MESSAGE PREPARATION AND RECEPTION
*3 Camps is much faster than current manual procedures
*1 3. S̲Y̲S̲T̲E̲M̲ ̲F̲U̲N̲C̲T̲I̲O̲N̲S̲
*1 E̲n̲v̲i̲r̲o̲n̲m̲e̲n̲t̲ ̲I̲n̲t̲e̲r̲f̲a̲c̲e̲s̲ ̲t̲o̲ ̲C̲A̲M̲P̲S̲
*3 CAMPS is a system which assists users in message preparation
and reception and which communicates with other user
systems, either directly or through a network. In this
context it can also function as a back up gateway for
other user systems which have lost connection to their
primary network.
A generic layout of the CAMPS Centers and the interconnecting
network is shown in Figure 3.
For CAMPS the primary network system will be a separate
system which utilizes a store and forward message transmission
system based on ACP127 procedures. This network transmission
system establishes a communication network between
all the NATO countries. It uses both terrestial and
satelite communication.
CAMPS is also interfaced to CCIS dataprocessing and
other message processing systems and is able to handle
traffic from these systems in case of temporary loss
of their primary networks.
CAMPS will play a very essential role in the information
gathering process of any Command and Control Informtion
System. CAMPS will assist the user in preparing reports
for CCIS by use of preformatted message using ADat-P3
procedures. The general message processing facilities
in CAMPS are extended by an ADat-P3 compiler, allowing
NATO to define specific message formats for all preformatted
reports. The compiler provides NATO with great flexibility
in the future because message formats can easily be
modified as a consequense of changes in requirements,
*3 Figure 3
*2 GENERIC LAYOUT OF CAMPS
*3 Message Processing Centers in Europe and their
*3 interconnecting network
ADat-P3 messages are highly structured. This structure
is programmed into CAMPS so that correct formats are
enforced by CAMPS. The structure is defined as subsets
or lines of fields within a message, and CAMPS will
ensure that the user does not omit any informtion.
When CAMPS has ensured that the message is correctly
entered, it can be processed automatically and a CCIS
database can be updated without human intervention.
Finally CAMPS interfaces to low speed communication
lines which are either point-to-point lines or lines
to TRC, Torn tape Relay Centers.
C̲A̲M̲P̲S̲ ̲C̲o̲m̲m̲u̲n̲i̲t̲y̲ ̲o̲f̲ ̲U̲s̲e̲r̲s̲
The system functions of CAMPS are provided for three
groups of users:
*2 E̲n̲d̲ ̲U̲s̲e̲r̲s̲ are those persons who prepare and receive
messages through CAMPS. They are the persons who benefits
most from CAMPS implementation.
*2 S̲u̲p̲e̲r̲v̲i̲s̲o̲r̲y̲ ̲p̲e̲r̲s̲o̲n̲n̲e̲l̲ are the communication center
personnel who assist CAMPS in providing its services
to the end users. The supervisor and his assistants
control all system tables within CAMPS. Security features
and addressing information such as directories of headquaters
are controlled by the supervisors.
The Message Distribution Control Operator (MDCO) one
of the supervisor assistants, will assist CAMPS in
distribution of incoming messages that can not be distributed
automatically. For example if a message has been prepared
outside a CAMPS without computer assistance it might
contain unrecoverable errors which makes it impossible
to derive the destination. The MDCO will insert a list
of suitable recipients and send for automatic distribution.
The MDCO can also initiate redistribution of messages,
if the original distribution was not appropriate.
The Message Service Operator (MSO), is another supervisor
assistant who assists CAMPS when incoming messages
cannot be processed automatically because of nonconformity
with the ACP127 rules. For example, certain required
information might be missing or misplaced. The MSO
will control the processing of those messages.
S̲y̲s̲t̲e̲m̲ ̲O̲p̲e̲r̲a̲t̲o̲r̲. The MSO also assist the user in the
preparation of outgoing messages where there is uncertainly
no addressing information. This person is responsible
for maintenance, engineering and configuration changes
of the computer. He controls all the elements of the
flexible and modular computer which is dualized in
all vital areas.
M̲e̲s̲s̲a̲g̲e̲ ̲P̲r̲e̲p̲a̲r̲a̲t̲i̲o̲n̲
The user functions that CAMPS provides are primarily
message preparation at a visual display unit (VDU).
The VDU's are very user-friendly in that they provide
formatted screen layouts with keywords in front of
all required entry fields. This approach allows a user
to compose messages without detailed knowledge of the
ACP127 procedures.
The VDU in CAMPS is a highly intelligent device. Syntactical
checks are performed by the VDU to give rapid feedback
to the user. All data entry fields have specified attributes,
e.g. entry mandatory or optional, entry only numeric,
only alphabetic or both (alpha-numeric). Maximum field
length is also indicated. Figure 4 shows a typical
terminal display for message preparation.
After entry of the data, the user initiates transmission
of data to the main computer which performs semantic
checks. For example means of a directory of all headquaters,
CAMPS can validate the addresses. The user can also
use an abbreviated numerical reference instead of the
long, plain language addresses of recipients and so
save valuable time during preparation.
If errors are discovered during validation of the entered
data, CAMPS provides error indications to assist the
user in correction.
When the message has been validated and accepted as
error free by CAMPS, the user can submit it for coordination
to other users. In this way CAMPS provides the feature
of an electronic mail system. Messages submitted for
coordination by one terminal are queued at all other
nomminated terminals.
The users requested to coordinate read the message
and prepare comments for the message drafter. A comment
is a free format message which can be drafted at one
terminal and sent to one or more terminals at the same
CAMPS site. Besides being used in connection with coordination
of messages, it can be used as a conferencing medium,
where two or more users via the CAMPS comment function
exchange information in an online environment.
The comments made by coordinators will be sent back
to the message drafter, who can then edit the original
message as necessary. A new coordination round might
be initiated or the message can be submitted for release
at a terminal position manned by a user with release
authority and special release capabilities.
Queuing of messages is performed on a priority basis,i.e.
level of urgency. This ensures that urgent message
are handled before routine messages. At the top of
the VDU screen there is a display of the number of
messages in each priority queue to help the user plan
his task priority.
After release, CAMPS performs the final conversion
of the message to ACP127 and selects an outgoing channel
to be used. This selection is based on information
in the message and table data in CAMPS. A vital point
in channel selection is the check between security
classification of the message and the security classification
of the channel. CAMPS can provide four alternate channels
to be checked for security levels for an outgoing message
before manual assistance will be necessary.
*3 Figure 4
*2 CAMPS MESSAGE PREPARATION
*3 Reduction in errors due to fase of service
M̲e̲s̲s̲a̲g̲e̲ ̲R̲e̲c̲e̲p̲t̲i̲o̲n̲
Messages received at a CAMPS will be distributed automatically
if they are in accordance with the ACP127 procedures.
After validation CAMPS will use the Subject Indicator
Code (SIC) to derive which terminals should have a
copy of the message. This procedure is controlled by
internal tables maintained by the supervisor. First
the SIC is used as an entry to define the standard
distribution list to be applied. This list in turn
contains a number of action-recipients and information-recipients.
If the message does not contain a SIC or if the SIC
code is unknown, the system will queue the message
for manual assistance at the MDCO position. The MDCO
can redistribute a message in any case where the automatic
distribution scheme has proved insufficient.
CAMPS delivers messages to terminals by putting them
in queues, one queue for each of the 4 priority levels,
and updates the queue status information at the top
of the VDU screen.
When the user sets his terminal in reception mode he
can display the messages, one by one. He can either
delete them or let them remain in the queue for later
action by himself or another user. If he wants a hardcopy
of the message he can order this by asking for a PRINT.
This causes the message to be routed to a logically
associated printer unit. The printers can be shared
by several VDU's.
Instead of routing messages to VDU terminals with subsequent
user requested rerouting to a printer, CAMPS can also
route messages directly to a printer. For example,
copies intended for action-recepients might always
be printed, whereas copies intended for information
recepients are only sent to VDU's where the user then
subsequently decides if he wants a hardcopy. The distribution
mechanism is very flexible and it is easily adaptable
to the needs and circumstances at each installation.
*1 4. E̲Q̲U̲I̲P̲M̲E̲N̲T̲ ̲D̲E̲S̲I̲G̲N̲
*3 The CAMPS system is implemented on the CR80 family
of computers, produced by Christian Rovsing A/S. This
computer family is a very flexible, modular system
which allows many different computer configurations:
from small minicomputers intended for commercial systems
or front end processors; through extremely reliable
systems, like CAMPS, using redundant elements for back
up; to huge integrated complete systems, e.g. a CAMPS
integrated with a communication subsystem as a node
in a network. Evolutionary growth of a CAMPS with a
few CCIS features such as enforcement of timely reporting
of preformatted messages and automatic accumulation
of these reports to a later configuration where the
CCIS aspects are more dominant than the message processing
and switching aspects itself, is feasible.
The concept behind the modularity and flexibility of
CAMPS hardware can best be described in a hierachical
top down fashion. The building block at the top level
is the secure rack. One, two or many racks may be joined
together to form rack groups containing all the lower
level equipment. Groups of racks can also be interconnected
if the computer room layout so dictates.
The second level element is a crate. Several crates
may be installed in one rack. There are three different
types of crate, a processing unit, channel unit and
adapter unit.
The processing unit (PU) contains modules for CPU's
and memory plus interface adaptors and a power supply.
Integral with the crate itself, forming a backbone,
computer buses are installed which interconnect all
processing elements. The modularity and generality
of this concept is so flexible that the individual
modules may be put in the crates, as books are placed
on a bookshelf. A PU may contain from 1 to 5 CPUs
and up to 1 Megaword of memory.
If more than one PU is installed in a computer (in
CAMPS two PUs are included), they are interconnected
via fast transfer buses. The upper limitation for the
number of PUs in one computer is 16, so a CAMPS has
enough processor expansion capability for any imaginable
application. Performing the extension causes minimal
interferance to the operational CAMPS.
The channel unit (CU) contains modules for external
interfaces, i.e. communication lines and discs, etc.
Extension memory is installed here if 1 megaword of
memory for each PU is not sufficient. CU's can be added
as required to provide additional terminals, external
lines discs, tapes, etc.
The adaptor crate contains modules for special line
adaptors, e.g. adapters for low signaling levels and
optical multiplexors with transceivers.
CAMPS equipment is shown in Figure 5.
The level below the crate is that of individual modules,
all microprocessor based. This concept gives a highly
distributed system, where many functions are removed
from the CPU to the peripheral processors. This compartmentalization
principle also enforces security aspects because all
peripheral processors are physically separated.
*3 Figure 5
*2 CAMPS EQUIPMENT
*3 A system including PU's, CU's and distribution equipment
*1 S̲Y̲S̲T̲E̲M̲ ̲S̲E̲C̲U̲R̲I̲T̲Y̲
*3 Modern Defense Communication require a high degree
of communication security. This has from the outset
been designed into CAMPS in form of physical security,
equipment security, and software security.
The highlights of the CAMPS security features are:
1. All visual display units, printers and other similar
devices are connected to the CAMPS central processing
system with fiber optic cables that preclude EMI
problems.
2. The CAMPS processing system itself is installed
in EMI shielded racks.
3. All power and electrical signalling cables enter
the system through special filter equipment.
4. The software has been designed in a hierachical
structure that eases verification and provides
well defined inter-program interfaces.
Access to all data areas and files are controlled
by secure operating system functions and a specially
developed memory mapping hardware module.
5. All users interfacing the system are controlled
by several security mechanisms:
*5 - Physical locks
*5 - User authentication through use of sign-in
passwords and security interrogations
*5 - Authorization through use of operator clearance
levels combined with terminal and channel clearance
levels.
*1 5. E̲X̲P̲A̲N̲D̲A̲B̲I̲L̲I̲T̲Y̲
*3 The building block of the CR80 computer have been described
above. Because its modularity CAMPS is easily expandable
to cope with a changing environment.
One of the most likely reasons for expansion is change
in data and traffic quantities. If traffic flow increases,
additional CPUs can be added. Even if the increase
is considerable drastic, i.e. 100 % or more, extra
PUs can be installed to account for the extra demand
of processing power.
An increasing traffic flow may require more disc storage
which can easily be accomodated by providing additional
CUs. The most striking fact about this expansion is
that modules are not replaced by more powerful modules
hence making the old modules obsolete; in CAMPS new
modules are added in an incremental way making the
expansion costs as low as possible. Also, the modularity
of CAMPS ensures that expansion proceeds smoothly in
small steps rather than in very large and costly equipment
additions.
It is also a possibility to reduce a CAMPS configuration,
if traffic becomes less or if a new site is needed
where a user traffic flow is less than presently provided
for.
CAMPS has already been planned to become a gateway
between different systems. If it is found desirable
to interface CAMPS to public networks like the X.25/X.75
type of network, this can be done by adding another
rack with an interface processing element containing
a PU and a CU.
The capabilities of CAMPS to collect reports using
Adat-P3 formats have been described. These capabilities
can be expanded with manipulation and processing of
these reports and display of results on VDU's or graphic
consoles.
When experience has been gained by the military users,
larger files can be added to provide CAMPS hosted CCIS
databases with displays. At that stage, the primary
communication network, which is a store and forward
message switching network, may not be adequate. A more
generalized network system based on packet switching
or virtual circuits might then be desireable.
In this approach a general transport network can be
established and used for e.g. transmission of radar
data for remote display, or giving a user remote access
to all network subscribers (sources of data). Via this
remote access facility, sharing is made easier, for
example dedicated computers with spare part inventory
information, computers with special programs like human
language translaters, etc. can be used without human
intervention.
CAMPS expandability possibilities are illustrated in
Figure 6.
*3 Figure 6
*2 CAMPS EXPANDABILITY
*3 Modular equipment allows cost effective
*3 expansion without development
*1 III DEFENSE DATA COMMUNICATION
ENGAGEMENT AT CHRISTIAN ROVSING A/S
B. A NATIONAL STRATEGIC NETWORK - FIKS
*1 A̲ ̲N̲A̲T̲I̲O̲N̲A̲L̲ ̲S̲T̲R̲A̲T̲E̲G̲I̲C̲ ̲N̲E̲T̲W̲O̲R̲K̲ ̲-̲ ̲F̲I̲K̲S̲
*1 1. O̲B̲J̲E̲C̲T̲I̲V̲E̲ ̲
The objective of FIKS is to provide a fully integrated,
tri-service communications network for the Army, the
Navy, and the Air Force of Denmark. FIKS provides rapid
and reliable communication of adequate capacity, incorporating
a high degree of security and Surviveability. Additionally,
FIKS is expandable - in capacity and function - so
that new systems and future developments do not render
FIKS obsolete for many years to come.
*1 2. B̲E̲N̲E̲F̲I̲T̲S̲
FIKS meets all stated requirements for speed, capacity,
security, reliability and expandability.
It is possible to deliver signals of the highest priority
to the correct address in less than 2 minutes. The
system manages a traffic load of 2500 incoming and
17,000 delivered signals per hour. The security provided
ensures that military messages of highest classification
may now be transferred automatically, and therefore
messages previously sent by courier are sent rapidly
via FIKS - all traffic being automatically encrypted.
Availability is ensured by fault-tolerant equipment,
dualization and components of the highest reliability.
Finally, FIKS was planned from the start to accomodate
connection to other networks. Via a secure gateway,
FIKS is, for example, connected to NATO's automated
telegraph network, NICS/TARE. Additionally, the data
transfer facility accomodates integration with voice
communication networks in the future.
In brief the advantages of the FIKS network are:
- More r̲e̲l̲i̲a̲b̲l̲e̲ communications through computer con-
trol, equipment dualization and system redundancy;
- Higher s̲u̲r̲v̲i̲v̲a̲b̲i̲l̲i̲t̲y̲ through multiple interconnec-
tions, alternative paths, and automatic rerouting;
- Improved s̲e̲c̲u̲r̲i̲t̲y̲ through message and data encryp-
tion and limited access;
- Greater e̲f̲f̲i̲c̲i̲e̲n̲c̲y̲, faster delivery and higher
throughput through real-time, multiplexed use of
network facilities;
- Tighter c̲o̲n̲t̲r̲o̲l̲ through centralized computer coor-
dination, supervisor visibility, and automatic
col- lection of statistics and status information;
- Operational s̲i̲m̲p̲l̲i̲c̲i̲t̲y̲ through computer-aided message
preparation and entry, automatic distribution,
and minimum operator intervention;
- Easier e̲x̲p̲a̲n̲s̲i̲o̲n̲ through flexible, common and interchangeable
hardware/software modules.
3. S̲Y̲S̲T̲E̲M̲ ̲F̲U̲N̲C̲T̲I̲O̲N̲S̲
The FIKS network consists of up to 15 nodal switching
centers, interconnected by internodal trunk lines,
ope- rated at speeds up to 64 KBPS.
The network provides two types of services:
M̲e̲s̲s̲a̲g̲e̲ ̲S̲w̲i̲t̲c̲h̲i̲n̲g̲: Store and forward message switching
of military messages. Messages may be entered in the
ACP127 format or in a simplified message format called
SMF from teleprinters or VDUs.
C̲i̲r̲c̲u̲i̲t̲ ̲S̲w̲i̲t̲c̲h̲i̲n̲g̲: Transparent transfer of data between
computers and terminals of any type and protocol.
The switching technique is based on a special packet
switching method which ensures rapid delivery with
only small variations. By this means the network is
suited for transfer of real time data like radar track
data and digital voice.
N̲E̲T̲W̲O̲R̲K̲ ̲O̲V̲E̲R̲V̲I̲E̲W̲
The nodal switching centres are configured with three
functional entities:
the NODE - providing access to FIKS for data termi-
nals, interfacing MEDEs, and performing
network-oriented functions common to both
data and message traffic
the MEDE - Message Entry and Distribution Equipment,
providing access to FIKS for communications
centers and performing terminal-oriented
functions related to message traffic
the SCC - System Control Center, providing network
supervision and control, and functions
as a center for software development and
maintenance.
These FIKS system elements may be co-located and physically
integrated.
Initially, FIKS is structured as an 8-NODE grid network
whose topology, shown in Figure 1, is described in
the sections to follow.
M̲E̲S̲S̲A̲G̲E̲ ̲U̲S̲E̲R̲S̲
Message users are served through a number of COMCENTERS.
About 150 message terminals - assigned to the COMCENTERS
- are given access to FIKS through dedicated or multiplexed
low and medium speed circuits terminated in the NODE/MEDE
processors. All message traffic is encrypted and message
traffic rates between 50 and 2400 bps can be accomodated.
*3 Figure 1
*2 FIKS NODAL NETWORK AND TERMINALS
*1 D̲A̲T̲A̲ ̲U̲S̲E̲R̲S̲
Data users, consisting initially of 12 data systems
ex- change information through FIKS on a continuous
or non- continuous basis through direct interconnections
with the Node processors and internodal trunk. Up to
15 dif- ferent data users with speeds ranging from
300 - 4800 bps may be multiplexed on each 9.6 kbps
trunk. Data channel set-up time is less than 75 msec
per Node and delay variation with respect to set-up
time is less than 50 msec per Node.
*1 N̲E̲T̲W̲O̲R̲K̲ ̲S̲U̲P̲E̲R̲V̲I̲S̲I̲O̲N̲
The entire FIKS network is monitored and supervised
by two System Control Centers, SCCs. The SCCs handle
the exchange of messages between FIKS and NICS-TARE
on a fully automatic basis.
*1 T̲R̲A̲F̲F̲I̲C̲ ̲S̲E̲C̲U̲R̲I̲T̲Y̲
*3 FIKS handles all security classifications of narra-
tive messages and data transmission as well as 4 categories
of special messages. Password checks ensure that only
authorized viewers will be allowed to examine message
content.
Provisions have been made for security class marking,
protection of stored messages and unauthorized retrieval,
message deletion, and special handling procedures.
Crypto-graphic security equipment protects all trans-
missions. Crypto equipment is of the type approved
by NATO, generically referred to as DOLCE. Automatic
de- tection of crypto garbling prevents loss of information.
Data streams requiring security are terminal-to-termi-
nal encrypted and routed through FIKS without need
for decryption and re-encryption at intermediate nodes.
Stable timing is provided from frequency standards
to maintain end-to-end synchronization and bit count
inte- grity throughout the network for several weeks
without adjustment.
FIKS is designed to prevent misrouting, inadvertent
disclosure of plain text and unauthorized access and
retrieval. Nodal switching equipment is separable into
RED areas and BLACK areas.
*1 M̲E̲S̲S̲A̲G̲E̲ ̲C̲A̲T̲E̲G̲O̲R̲I̲E̲S̲,̲ ̲C̲O̲D̲E̲S̲ ̲A̲N̲D̲ ̲F̲O̲R̲M̲A̲T̲S̲
*3 Four categories of traffic are handled: (1) narrative
messages with precedence and multiple addressees in
FIKS standard message format (SMF) with the essential
elements of the ACP-127 format; (2) service messages
using an abbreviated format; (3) continuous data requiring
virtually dedicated channels with minimum delay and
routed as an un-interrupted bit stream; and, (4) discontinuous
data requiring channels on a call-up basis with predictable
set-up time and delay. For message traffic, FIKS will
accept either 5-level (Baudot/ITA-2) or 7-level (ASCII/ITA-5)
codes; inter- nally, message processing and storage
will be in ASCII code.
For data traffic, FIKS accepts any format or code,
as FIKS is completely transparent to the formats and
protocols used for the continuous and discontinuous
data categories.
.
Narrative messages are modified before transmission
by addition of an envelope containing FIKS internodal
routing and local address information, and the original
messages are restored at the destination terminals.
Internal to the FIKS network, between Nodes, all traf-
fic is handled as packets compatible with HDLC protocol.
A special ECD protocol is used between FIKS and NICS-TARE.
*1 M̲E̲S̲S̲A̲G̲E̲ ̲E̲N̲T̲R̲Y̲,̲ ̲S̲T̲O̲R̲A̲G̲E̲ ̲A̲N̲D̲ ̲D̲I̲S̲T̲R̲I̲B̲U̲T̲I̲O̲N̲
*3 Messages enter the FIKS network from a number of mes-
sage preparation and receiving terminals such as tele-
printers and visual display units. The total capacity
of the MEDE is 242 terminals and 12 interfaces to host
computers. Message preparation is interactive with
prompts from the MEDE computer. An example of a message
preparation format is shown in Figure 2. The underlined
portions are either prompts or other computer inserted
information.
Message terminal operators can use a number of inter-
active procedures such as:
- preparation (4 types)
- coordination
- release
- retrieval
- readdressing
- distribution, local
- log on
- log off
- special handling
- editing
FIKS MESSAGE PREPARATION FORMAT
(CR) = carriage return)
P̲R̲O̲C̲ PRE (CR)
A̲B̲C̲ ̲1̲2̲3̲ (CR)
F̲O̲R̲M̲A̲T̲T̲E̲D̲ ̲M̲E̲S̲S̲A̲G̲E̲ A21 (CR)
P̲R̲E̲C̲ ̲A̲C̲T̲ O (CR)
P̲R̲E̲C̲ ̲I̲N̲F̲O̲ R (CR)
F̲M̲ / (CR) C̲H̲O̲D̲D̲E̲N̲
T̲O̲ AIG 1601 (CR)
X̲M̲T̲ (CR)
T̲O̲ E104 / (CR) T̲A̲C̲D̲E̲N̲
T̲O̲ (CR)
I̲N̲F̲O̲ X115 (CR)
I̲N̲F̲O̲ (CR)
B̲T̲
C̲L̲A̲S̲S̲ NS (CR)
S̲P̲E̲C̲A̲T̲ (CR)
S̲I̲C̲ RHQ (CR)
.......TEXT............
NNNN (CR)
B̲T̲
D̲T̲G̲ / (CR) 0̲1̲2̲3̲4̲7̲z̲ ̲J̲A̲N̲
P̲R̲O̲C̲
*3 Figure 2
*2 FIKS MESSAGE PREPARATION FORMAT
The MEDEs are manned 24 hours a day and MEDE super-
visors have control over the security and traffic of
the system and its terminals. A number of special pro-
cedures are available for the supervisor, e.g.:
- distribution (2 types)
- control of terminal queue status
- re-arrangement of queues
- relocation of queues
- re-routing of terminal traffic
- block/unblock terminals
- security interrogation of terminals
- establishment of PTT data net connections
- updating of route and address tables
- security profile handling
- call-up of daily traffic statistics
Full accountability is provided for all messages.
Messages are queued by precedence to the Node for network
routing and for automatic distribution to local addressees.
All outgoing and incoming messages are stored at the
MEDEs for 10 days. SPECIAL CATEGORY (SPECAT) messages
will be deleted from local storage after transmission
and delivery. Retrieval of messages from 10 day storage
by authorized users are provided. Messages can be retrieved
by message identification subject indicator codes and
date/time indication.
M̲E̲S̲S̲A̲G̲E̲ ̲R̲O̲U̲T̲I̲N̲G̲ ̲A̲N̲D̲ ̲D̲A̲T̲A̲ ̲S̲W̲I̲T̲C̲H̲I̲N̲G̲
Message traffic is relayed from the originating MEDEs
through intermediate FIKS Nodes to the destination
MEDEs, and data traffic is transferred between terminals
directly interconnected to FIKS Nodes over internodal
trunks. The associated message routing and data line
switching functions are allocated to the Node processors.
Messages received by the Node are routed to other Nodes
or delivered to the locally connected MEDE on the basis
of routing indicators and precedence contained in a
special header. Each Node is interconnected to adjacent
Nodes through at least 3 independently routed trunks.
The optimum trunk route to the final destination Node
is based upon shortest route (minimum hop) and network
connectivity. A routing algorithm is used which allows
…86…1 …02… …02… …02… …02…
the Node to be independent of SCC control. SCC will
be informed of all changes in the network and calculate
routing tables for optimization of the network traffic.
The SCC routing algorithm uses weighted delay factors
for the individual trunks. These weighting factors
will be derived from the traffic queue-reports and
be used to calculate message routing tables which are
down-loadable to the Nodes.
The routing tables contain three alternative routes
per destination and the Nodes select the proper routes
from the tables based on trunk queue lengths. If both
SCCs are in-operative, the Node/MEDE supervisors can
manual- ly update the tables.
Data traffic - both continuous and discontinuous -
is switched through predetermined routes over internodal
trunks. Each data user is allocated a primary and a
secondary route through the network. If the primary
route fails, the secondary route is automatically established.
Switch-back to the primary route is con- trolled by
supervisory commands.
End-to-end set-up and transmission delays will be less
than 1 second. The Node is transparent to data traffic;
all data traffic is in the black. Crypto synchronization,
channel coordination, error control, and recovery procedures
are terminal-to-terminal or computer-to- computer.
*1 S̲Y̲S̲T̲E̲M̲ ̲S̲U̲P̲E̲R̲V̲I̲S̲I̲O̲N̲,̲ ̲C̲O̲N̲T̲R̲O̲L̲ ̲A̲N̲D̲ ̲M̲A̲I̲N̲T̲E̲N̲A̲N̲C̲E̲
*3 Centralized supervision and control of the overall
FIKS network maintains network efficiency and regulates
or restores service in case of congestion, outages,
or failures. Continuous network status is monitored
and displayed at System Control Centers. Two SCCs are
provided but neither is dualized; back-up is geographic
resulting in increased surviveability. Both SCCs may
be on-line with one exercising network control and
the other on standby monitoring the network; or, the
second may be off-line and dedicated to program development,
maintenance, or training.
The SCCs exercise control of the network by use of
a number of procedures, e.g.:.
- threshold setting for trunk queue lengths
- threshold setting for message retransmission rate
- control of SCC switchover
- change of tables
- request of diagnostic results from Node/MEDEs
- open/close trunks
Control messages from the Node/MEDEs concerning traffic
queues, trunk and Node status, retransmission rate
and, equipment availability, etc. are transmitted to
the SCCs; from this, statistics are gathered, alarm
condi- tions noted, and reports presented to allow
timely net- work decisions by supervisory personnel.
A log of con- trol messages and SCC action provides
an audit trail to trace all network control actions.
Downline loading of routing, security and address tables
from the SCC to the network permits selective re-routing
of message traffic, change of routing plan, reconfiguration
of the network, and change of security tables.
The current operational status of the FIKS nodal net-
work is displayed on a color display, dynamically updated
by reports and alarms from the network.
The open/closed status of each internodal trunk and
ac- tive PTT back-up channels as well as configuration
and availability of each Node/MEDE and SCC are displayed.
Statistics are gathered by the SCC from control mes-
sages, periodic reports and traffic received from the
network. Message flow, trunk usage, queuing delays,
outages, equipment up-time, and other statistics will
be available for off-line statistical analysis, reports
and network planning. A summary message traffic report
will be automatically generated and distributed every
24 hours to the Node/MEDEs.
The interchange of message traffic between the FIKS
and NICS-TARE network will be performed by SCCs. TARE
may send messages to FIKS terminals; national routing
indi- cators and addressees will be recognized and
the mes- sage will be converted from ACP-127 format
to FIKS Standard Message Format for routing and distribution
on the FIKS network. Similarly, FIKS terminals will
send messages to TARE Using NATO addresses.
Maintenance of the system is performed partly by Node/MEDE
supervisors crosstrained to operate the off-line diagnostic
programs, change modules and perform manual switchover,
and partly by technicians located at the two SCCs and
a technician mobile team which can be called out to
the different sites to locate and repair faults. Software
personnel will be located at the two SCCs.
*1 4. E̲q̲u̲i̲p̲m̲e̲n̲t̲ ̲D̲e̲s̲i̲g̲n̲
*1 F̲I̲K̲S̲ ̲G̲e̲n̲e̲r̲i̲c̲ ̲E̲l̲e̲m̲e̲n̲t̲s̲
*3 The generic elements of FIKS and their interrelation-
ship are shown in Figure 3. The various demarcation
points which will be encountered between the Node/MEDE/SCCs,
FIKS Network, COMCENTERs, message terminals, data systems,
computers, and data terminals are also indicated.
The FIKS system is implemented on Christian Rovsing
A/S' CR80 computer system.
*3 Figure 3
*2 FIKS GENERIC ELEMENTS
5. E̲x̲p̲a̲n̲d̲a̲b̲i̲l̲i̲t̲y̲
The FIKS nodal switching center are based on a multiprocessing
concept that provides a growth potential from 1 to
30 million instructions per second (MIPS). Growth
is implemented by simply adding more modules of equipment
instead of replacing old equipment. The modularity
of the system supports this expandability and enables
extensions to be performed without system interruption.
In its actual configuration, FIKS has an installed
capa- city for 25% growth and a wired capacity for
three times the actual load. In addition, the network
has been designed for distribution of electronic mail
and for handling of digital telephone transmission.
III DEFENSE DATA COMMUNICATION
ENGAGEMENT AT CHRISTIAN ROVSING A/S
…01…C. UPGRADE OF A TACTICAL CCIS SYSTEM
HAWK CONVERTER
*1 H̲A̲W̲K̲ ̲C̲O̲N̲V̲E̲R̲T̲E̲R̲
*1 1. O̲B̲J̲E̲C̲T̲I̲V̲E̲
The basic Improved HAWK (IHAWK) missile system for
air defense has been operational since 1960, using
a Missile Battery Data Link (MBDL) protocol for communication
between the B̲attery O̲perating C̲enter (BOC) and IHAWK
batteries. To take advantage of numerous advances
in technology, a new HAWK improvement program (PIP)
was initiated. This program resulted in a superior
protocol with expanded information capabilities, the
A̲rmy T̲actical D̲ata L̲ink (ATDL) protocol for inter-battery
communication. (This improvement program does not include
changes to the Battery Operating Center).
To enable inter-communication between batteries - using
the ATDL protocol and communication with old Battery
Operating Center - accepting only the MBDL protocol,
an A̲TDL M̲BDL C̲onverter (AMC) was designed. The AMC,
implemented by a CR80 computer, is located in the same
shelter as the Battery Operating Center.
As the installation in the mobile shelter imposes some
environmental requirements that are more severe than
usually imposed on normal computer equipment, a major
objective has also been to provide equipment that can
operate under such conditions.
2. B̲E̲N̲E̲F̲I̲T̲S̲
The benefits obtained by use of the ATDL/MBDL converter
are:
- The PIP modified IHAWK batteries can be controlled
from an unmodified Battery Operating Center.
- Information received from one battery is forwarded
to all other batteries; this enables a more detailed
information exchange between the batteries.
3. S̲Y̲S̲T̲E̲M̲ ̲F̲U̲N̲C̲T̲I̲O̲N̲S̲
The Basic IHAWK configuration, shown in Figure 1, provides
communication between the Battery Operating Center
(BOC) and up to 8 IHAWK batteries by means of the Missile
Battery Data Link (MBDL), which has the relatively
limited message structure consisting of:
o REFERENCE MSG - from BOC to battery
o DESIGNATE MSG - from BOC to battery
o STATUS MSG - to BOC from battery
The REFERENCE MSG provides target coordinates and is
entered by track/ball control of the cursor on a Plane
Position Indicator (PPI) display.
The DESIGNATE MSG is sent by pressing one of several
possible buttons on a panel in front of the operator.
The STATUS MSG returns information from batteries to
the BOC by lighted status lamps on the panel in front
of the operator, e.g. EFFECTIVE.
After the PIP improvement of the IHAWK batteries, however,
communication with these batteries is performed by
means of the Army Tactical Data Link (ATDL) protocol
which provides a superior data link with expanded information
capabilities - see Figure 2.
The ATDL message types used for communication with
PIP modified IHAWK batteries are:
- TEST MESSAGE which provides the means to monitor
the status of a point-to-point data link
- DATA REFERENCE MESSAGE which identifies the originator
and his position
- AIR TRACK POSITION MESSAGE which is used to report
position, identity, and status of air tracks.
- AIR POSITION AMPLIFY MESSAGE which is used to give
additional information concerning an air track.
Figure 1
BASIC HAWK CONFIGURATION
Figure 2
PIP MODIFIED IHAWK CONFIGURATION
- SPECIAL POINT POSITION MESSAGE which is used to
report position and identification of special points
- ECM DATA MESSAGE which is used to report ECM jam
strobes
- IFF/SIF MESSAGE to report IFF/SIF of an air track
- STATUS MESSAGE to report status of the originator
- COMMAND MESSAGE to give a command to the addresse
- TRACK MANAGEMENT MESSAGE which provides those management
actions necessary to control the data exchange.
As the PIP modified batteries are capable of receiving,
storing, and displaying airtrack information received
on the data link, information of this kind received
from any of the batteries is stored in the converter
and forwarded to all other batteries.
4. E̲Q̲U̲I̲P̲M̲E̲N̲T̲ ̲D̲E̲S̲I̲G̲N̲
The ATDL MBDL Converter is implemented on a CR80 computer.
The interfaces to the BOC and to the PIP modified IHAWK
batteries are shown in Figure 3. This Figure also shows
the hardware modules used to implement the converter.
In addition to standard processing modules, the design
includes some special modules:
- The MBDL Modem I/F and the ATDL Modem are modules
designed to meet the special modulation requirements
of the two protocols.
- The Line Termination Units (LTUs) are programable
modules, where the special frame formats of the
two protocols are implemented.
The Operators Panel, a wall-mounted unit installed
next to the BOC operator, is used to enter special
information required by the AMC into the system and
to display conflicts and line status to the operator.
Figure 3
ATDL/MBDL CONVERTER
A modular concept is also used for the software design;
the software block diagram is shown in fig. 4. The
AMC software provides two possibilities for module
communication, which are:
- Send Message/Await Answer
- Send Buffer/Receive Buffer
The first possibility is flexible, can be used for
ATDL/MBDL message transport, and allows synchronous
operation. The second possibility, used only for ATDL
message transport, provides high speed communication.
A queue priority system prevents dead locks and guarantees
efficient communication. Four priorities are provided:
- Line Surveillance Module (highest priority)
- Command/Status Handler
- ATDL track file Manager
- ATDL Message Sequencer (lowest priority)
Higher priority functions may interrupt lower priority
functions, but the lowest priority - ATDL Message Se-
quencer - cannot be interrupted; this guarantees complete
transmission of all message segments concerning one
track.
Finally, a data base is provided for storage of track
information, battery status and line status. The storage
provided to meet the requirements of the batteries
is much greater than the number of tracks which the
operator can physically input and update at the existing
BOC.
5. E̲X̲P̲A̲N̲D̲A̲B̲I̲L̲I̲T̲Y̲
At present within the BOC shelter, the expanded message
structure provided by the ATDL link is internal to
the AMC and, therefore, not available to the operator
of the BOC.
Figure 4
HAWK SOFTWARE BLOCK DIAGRAM
It is feasible, however, to provide the operator with
all information carried by the ATDL link by addition
of a display interface to the AMC, and by installation
of a display capable of showing the information. Rapid
data transfer from the AMC to the display interface
could be handled by a Direct Memory Access (DMA) link,
and display communication would be by standard V24
serial link. An improved BOC configuration is shown
in Figure 5.
Figure 5
FUTURE BOC IMPROVEMENT
III DEFENSE DATA COMMUNICATION ENGAGEMENT
AT
CHRISTIAN ROVSING A/S
D. COMMERCIAL CCIS
VIDEOTEX
*1 V̲I̲D̲E̲O̲T̲E̲X̲
*1 1. O̲B̲J̲E̲C̲T̲I̲V̲E̲
VIDEOTEX is the name given to a low cost, easy to use,
two way information service for homes, offices, libraries,
schools, railway terminals, etc. The main objective
of VIDEOTEX is to provide subscribers with information
- text and graphics - at an ordinary TV console.
Information provided to subscribers comes from a VIDEOTEX
Computer Center (VCC) data base maintained by participating
suppliers of information. Information can be updated
in several ways:
o on-line immediate edit - supplier determines when
to update
o on-line bulk edit - supplier can transmit new data
to VCC at any time, VCC updates at scheduled times
o off-line magnetic tape transfer - VCC updates at
scheduled times
o direct connection through VCC between subscribers
and suppliers.
A subscriber establishes a two-way information session
via common carrier switched lines by dialing VCC. If
an input port is available, VCC accepts the call request
and gives access rights.If a call request cannot be
accepted, the subscribed receives a busy tone - as
in normal telephone usage.
A subscriber can access information and can also transmit
a message to other subscribers or suppliers of information.
Finally, interactive services between a subscriber
and the VCC can be provided.
It should be noted that the individual subscriber does
not necessarily have access to all services available,
but rather only to the services which he needs; this
results in lower costs when a lesser level of service
is required.
*1 2. B̲E̲N̲E̲F̲I̲T̲S̲
VIDEOTEX technology offers the possibility of electronic
information distribution to subscribers cost competitive
with classical information distribution media in use
today.
Major advantages of VIDEOTEX lie in its convenience
of use and in its provision of access to up-to-date
information using normal TV consoles as terminals and
common carrier lines for transmission.
Information search is easy to carry out, and use of
both primary and secondary keywords effects one-command
information retrieval.
As VIDEOTEX is designed according to an internationally
agreed layered software structure. Future expansion
of system functions can be achieved by simply adding
functional modules.
3. S̲Y̲S̲T̲E̲M̲ ̲F̲U̲N̲C̲T̲I̲O̲N̲S̲
The principal functions offered by VIDEOTEX are:
- Information Retrieval
- Message Service
- On-line Applications
- Transaction Service
- Closed User Groups
- On-line Editing
In the sub-sections to follow, each principal function
is outlined.
I̲N̲F̲O̲R̲M̲A̲T̲I̲O̲N̲ ̲R̲E̲T̲R̲I̲E̲V̲A̲L̲
By using this function, a subscriber selects display
of information - one screen image (frame) at a time
- from a wide choice of possibilities. Selection of
frames is via a key pad (numeric keys plus a few special
keys) or keyboard (alphanumeric and special keys),
and three methods of selection are provided:
1. Hierarchical Search - based on "menuframes", each
allowing the subscriber to choose the desired continuation
frame and thus refine a choice until the required
information is at hand.
2. Direct Page Choice - each page in the data base
(a page can include one or more image frames) is
identified by a page number of 1 to 14 digits;
a subscriber enters a page number and the first
image frame in that page is displayed; remaining
frames can be viewed sequentially.
3. Keyword Search - a disc resident subject index
converts keywords to page numbers.
M̲E̲S̲S̲A̲G̲E̲ ̲S̲E̲R̲V̲I̲C̲E̲
Facilities for transmitting messages from one subscriber/supplier
(user) to another subscriber/supplier are provided.
Users are notified of awaiting messages upon log-in
to the system.
O̲N̲-̲L̲I̲N̲E̲ ̲A̲P̲P̲L̲I̲C̲A̲T̲I̲O̲N̲ ̲S̲E̲R̲V̲I̲C̲E̲
This function provides data processing at VCC under
user control. Dedicated page numbers are associated
with applications, and frames used in these applications
contain formatted input/output fields.
T̲R̲A̲N̲S̲A̲C̲T̲I̲O̲N̲ ̲S̲E̲R̲V̲I̲C̲E̲
Pre-formatted forms can be filled in by the user and
returned to the originator.
C̲L̲O̲S̲E̲D̲ ̲U̲S̲E̲R̲ ̲G̲R̲O̲U̲P̲S̲
Access to specific areas of the data base is available
only to authorized members of a "Closed User Group".
There can be more than one closed user group, and users
may be authorized as members of more than one group.
O̲N̲-̲L̲I̲N̲E̲ ̲E̲D̲I̲T̲I̲N̲G̲
Suppliers of information can edit frames of information
on-line, i.e change frames without delays. This necessitates
an extended alphanumeric (editing) keyboard interfaced
to a modified TV console.
4. E̲Q̲U̲I̲P̲M̲E̲N̲T̲ ̲D̲E̲S̲I̲G̲N̲
An overview of the hardware structure is given in fig.1,
and the principal components are:
- VIDEOTEX Retrieval Unit
- VIDEOTEX Database Unit
- VIDEOTEX Input Unit
- VIDEOTEX Ex Database Unit
Each unit is a self-contained, operational computer
system and dedicated to specific sub-tasks. Interchange
of information between units is via the TDX-Bus, a
time division multiplex path with high bandwidth.
In the subsections to follow the principal hardware
units are described.
R̲e̲t̲r̲i̲e̲v̲a̲l̲ ̲U̲n̲i̲t̲
Each VIDEOTEX Retrieval Unit (VRU) is a self-contained
computer system whose hardware/software controls the
user dialogue and each VRU has 80 ports. In addition,
each VRU is equipped with one moving head disc containing
80M Bytes and one fixed head disc containing 5M Bytes.
Figure 1
VIDEOTEX COMPUTER SYSTEM
configuration showing modular design
The 80M Byte VRU disc can contain approximtely 30,000
frames (screen images) of information - assuming 1400
Bytes/frame. This number of frames should be adequate,
as experience shows that only 10% of all possible frames
are used in 90% of demands for information. Should
a frame to be displayed not be found on the VRU disc,
a request is sent to the VIDEOTEX database, and a data
transfer is effected. If space is available on the
80MB disc, the new frame is kept; if space is not available,
the new frame replaces one that is less likely to be
called.
The 5MB fixed disc contains standard frames of VCC,
log-on frames, message service frames, etc. Also stored
here is the primary keyword index. Additionally this
disc is used as a session allocated virtual memory
resource to gather statistics and accounting information.
V̲i̲d̲e̲o̲t̲e̲x̲ ̲D̲a̲t̲a̲b̲a̲s̲e̲ ̲U̲n̲i̲t̲
The VIDEOTEX Data B̲ase U̲nit (VBU) is a self-contained
computer system containing hardware/software to control
and maintain an internal database. The VBU is dualized
as it is a mandatory function of VIDEOTEX. Therefore,
the VIDEOTEX configuration contains 2 VBU's - one acting
as a back-up for the other. Thus it is possible to
reestablish the data base after a disc failure.
V̲i̲d̲e̲o̲t̲e̲x̲ ̲I̲n̲p̲u̲t̲ ̲U̲n̲i̲t̲
The VIDEOTEX Input Unit (VIU) is a selfcontained, operational
computer system containing hardware and software to
input data from information suppliers to the Videotex
system.
The VIU also provides facilities for editing of information.
Input and editing is provided either as bulk transfer
or as on-line editing.
Bulk transfer is provided either by means of Magnetic
Tape input or by means of bulk updating from a remote
off-line microprocessor-based intelligent editing terminal.
On-line editing is provided as an interactive application
service available to information suppliers having business
or residential terminals equipped with an editing keyboard.
There are 44 ports allocated for input. Of these, 8
ports are used for remote VIDEOTEX bulk-updating and
36 ports for on-line editing.
E̲x̲D̲B̲ ̲I̲/̲F̲ ̲U̲n̲i̲t̲
The VIDEOTEX ExDB I/F Unit (VEU) is a self-contained,
operational microprocessor providing 4 external database
lines to the VIDEOTEX System.
Available I/F protocols are:
- IBM 2780 BSC
- HDLC/X.25
- HDLC
- SDLC/SNA (3276, 3270
datastream compatible)
5. E̲X̲P̲A̲N̲D̲A̲B̲I̲L̲I̲T̲Y̲
The VIDEOTEX System Architecture (VSA) developed by
Christian Rovsing A/S is based on a comprehensive and
flexible approach; the system contains a number of
operational capabilities performed by distributed processing
elements which together provide the desired VIDEOTEX
Service.
Each processing element communicates with other operational
elements through a transmission network (e.g. X25 package
switching network, local area network, TDX-bus etc.)
System growth and expansion is, by virtue of the distributed
architecture, very flexible, and in fact the growth
potential is only a question of network capacity.
