Network service for data exchange

In a follow-up to his previous paper, Nigel Fenton describes the design and testing of a network service that supports the Tradacoms standards

The widespread use of telecommunications for the exchange of trading data between a matrix of users has been prevented by the lack of a practical telecommunications protocol standard. The Article Number Association specified and had built a network service that would over- come this problem and would support the Tradacoms standards for data communications. The background to the design of the system and the facilities that it offers are described. The results of a programme to test the service are discussed briefly and the requirements for operating the system are outlined.

Keywords: standards, electronic data exchange, tele- communications, protocols

Over 150 major UK companies exchange order, invoice and delivery note transactions electronically between their respective computer systems using the Tradacoms data-formatting standards published by the Article Number Association (ANA).

As has been described in a previous paper 1, this direct computer-to-computer exchange eliminates the need for manual key entry of data from paper documents. The resulting benefits include improved speed and accuracy of data exchange, reduced queries, improved transaction matching and faster authorization of documents and updating of ledgers.

Most users employ magnetic tapes as the principle medium for this exchange. For example, two major high- street retailers in the UK now receive over 70% of their invoice line data by this means, and they have developed streamlined procedures to facilitate the handling and processing of the incoming magnetic tapes.

Article Number Association (UI0 Ltd, 6 Catherine Street, London WC2B 5JJ, UK

The system is very successful; however, users have been aware for some time that further benefits could be derived from the use of telecommunications as the medium for exchange.

Telecommunications provide a fast, convenient means of data transfer arid should enable a user to channel all his incoming and outgoing data through one route rather than on a number of separate tapes or floppy discs, which must be physically transported.

The Tradacoms standards for electronic data exchange are machine independent and therefore present no barrier to the use of telecommunications. Indeed, some companies have arranged successful point-to-point telecommunications links with one or two trading partners for the exchange of orders or invoices.

However, one thing has militated against a more widespread move towards telecommunications for exchange between a matrix of users, this being the absence of a practical telecommunications protocol standard. Different hardware types conform to, or can emulate, different industry standards for telecommuni- cations protocols. These include prevalent varieties such as 2780, 3780, SNA (SDLC) and CO3.

Two users wishing to link their computers directly must select a mutually acceptable protocol if the exchange is to be successful. In addition, in many cases they must agree a mutually acceptable set of parameter options within that protocol. It is little wonder that only a small number of companies have attempted to establish such links with more than a few trading partners.

The problem is widely recognized, and international efforts are underway to develop a true standard protocol. It might, however, be some time before this standard is published and supported by commercially available hardware.

Another potential obstacle to telecommunications exchange arises because of its instantaneous nature. Exchange partners communicating via a direct, bilaterial

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link must agree mutually convenient times for the data exchange to be conducted. If the data recipient's order- processing cycle is ready to receive input at 4 a.m., then the sender must comply by issuingthe transmissic-', at this time: no sooner and no later.

However, because bulk trading-data often has little intrinsic value, companies do not usually need, nor can they afford, to be online with their trading partners in a real-time environment.

The solution to these two problems of protocol and scheduling incompatibilities was seen to be a low cost, offline, store and call-forward, value-added network supplying comprehensive protocol conversion to support all relevant computer hardware.

TRADANET NETWORK SERVICE

A specification for such a facility was drawn up by the ANA's Tradacoms Standards Group in 1983. Suppliers were invited to tender for the project, and ICL were selected to build and test an appropriate solution.

The service that was developed by the ICL Network Services Division, working with ANA, is called Tradanet. This is essentially a distributed, national network based on dedicated, paired System 25 ICL machines, which provides protocol conversion and an electronic postal service for data in the Tradacoms standard format (see Figures 1 and 2).

Store and call forward

Users can communicate with the service via a dial-up or leased-line connection to their nearest supporting

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Figure 2. Flow diagram of the sender to receiver process

network node. Subscribers to the service have an electronic postbox (a private area of disc storage) to which their data messages go for sorting and onward routing. Data is delivered to the intended recipient's electronic mailbox, from which he can collect it at his convenience.

Users can select listings of the contents of their electronic post and mailboxes and can perform house- keeping functions on these e.g. deleting files or stipulating the collection of specific files.

Protocol conversion

Since Tradanet can support a range of recognized communication protocols, each user need establish only one link to the service. Once the service has received the user's data in the protocol of his choice, it is routed around ICL's national X.25 network and converted into the protocol required for the recipient's machine. Thus the sending company can issue data for any number of trading partners, all potentially with different protocol

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requirements. In the long term, ANA and ICL intend to implement true intemational protocol standards when they are available.

SECURITY

From the outset, potential users stressed the importance of providing security and confidentiality of data in the system. They did not wish unauthorized users to access the service or to investigate the contents of their mailbox. It was also important that data destined for one trading partner should not be sent to the wrong place.

For these reasons, a range of security measures have been built into the service. These include the following:

• dedicated, paired processors, with controlled dupli- cation of stored data to enable recovery in the event of machine failure,

• physical security at processing sites, • restriction of use to authorized password holders, • operation of an accredited-user matrix, ensuring that

any user can send data to other users only if they have specifically agreed from the outset to accept that type of data (e.g. orders only) from the prospective sender,

• transparency of data content, whereby the network operator does not read or interpret the data content in any way: only the Start of Transmission data segment, containing sender and recipient details and passwords, is read.

Before the ANA could consider endorsing the service, a thorough testing programme had to be conducted.

NETWORK TRIAL

In July 1984, seven companies prepared to test the service. These companies (Boots, Cadbury, Fine Fare, Reckitt & Colman, Rowntree Mackintosh, Tesco and Waitrose) all had long experience of using the Tradacoms standards for bilateral exchange and so were well equipped to conduct tests of the service during its development phase. Progress during the trial was monitored by the ANA's Tradacoms working party and by the ANA Council.

The trial had the following four phases:

e: establishing the basic telecommunications link between the users and the service,

ol testing the ability of users to operate the service via custom written command software,

el exchanging data transactions in Tradacoms format and ensuring the integrity of transmission,

• monitoring the performance capabilities of the service.

Naturally, at all stages of the trial there were problems to be tackled and resolved. Most of these difficulties related to the achievement of smooth communication links. Differences in protocols and in the way different types of hardware interpreted the same protocol needed to be

overcome, as did the differences in users' operating systems and the way these interfaced with the network.

The trial demonstrated that business data could be routed securely between a matrix of users in a reliable and timely fashion. Inward transmissions submitted to the service were typically available for processing by recipients within one hour of despatch, even when a number of users were concurrently accessing the network. As a result of the successful completion of the trial in April 1985, ANA endorsed the service for national operation.

The service is of wide interest to users because it is a network service that does not stipulate the use of a particular hardware or protocol configuration and that can handle bulk data volumes. As the number of users of the service grows, the network should expand, with more processor nodes being added to bring local call connec- tion to most of the UK business community.

However, the integrity of the service is based on adherence to the Tradacoms standards for data formatting. Intending users need to adopt these standards to ensure that they meet the basic requirements for compatibility of the data structure.

USING THE SERVICE

When a company wishes to make use of the service, there are various key stages of preparation that it must undertake.

Conversion of data

The conversion of data from an in-house format to the Tradacoms standard, or vice versa, can be achieved using purpose written software or a commercially available package.

Development of command generator and listing software

For a user to access the service and to issue instructions, he has to develop simple, command-generating software. He also needs to prepare software that will print reports from the listing data issued, on request, by the service.

Production of line-driving software

The user will need to ensure that his telecommunications lines will successfully communicate with the network. The network has been designed as a noninteractive service, and users, therefore, must submit a pure stream of data that is free from JCL commands or other headings.

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C O N C L U S I O N

Over the next few months, interface software packages will be developed to facilitate user access to the service, particularly for those with limited data processing resources.

The objective is to provide a network that will effec- tively service the business communication needs of a wide cross-section of users. It is hoped that international

communication links and interfaces with related service networks, e.g. funds transfer, will follow in due course.

REFERENCES

1 Fenton, N 'Standards for electronic data exchange' CompuL Commun. Vol 7 No 4 (August 1984) pp 181-185

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