The CIMS Data-Link/Processing Analyser (CDA) is a tool for analysing the data transfer or processing properties of communications and processing systems. Its open architecture supports interfaces to a wide range of systems. The currently supported interfaces include:
X.25 German PTT Datex-P PSN
X.25 via ARINC 429 / Williamsburg
V.24 text-oriented VHF data link
VDL Mode 2
In order to investigate the properties of a communications or processing system a CDA is connected at both the transmitting and receiving ends of the data-link. Since synchronisation is ensured by radio clocks (DCF 77 or GPS) it is not necessary that both ends be at the same location.
Script-files define test scenarios, so allowing a flexible definition and automatic tests over hours or even days. During the performance of a test run transmit- and receive events are recorded and stored in logfiles. Precise time-stamps permit all manner of subsequent evaluation.
The script- and log-files are structured ASCII files. Logfile post-processors are available for the evaluation of transmission latency, error rates, loss rates and throughput. Modules for customer specific post-processing may be readily integrated.
The CDA features a modular and open architecture consisting of an intuitive Graphical UserInterface (GUI), a test execution kernel and system-specific interface modules. The interface module executes as an independent task and communicates with the Text Execution Kernel by a procedural interface; the resultant decoupling ensures that any adaptation to a particular system is limited to the interface module.
The user interface is an X-client application and, if so required, may be operated from an X-Server elsewhere in the network.
The CIMS Data-link/Processing Analyser is currently available for PC-platforms under Sun Solaris and Linux. A port to Windows-NT is in preparation.
CIMS Engineering & Systmes GmbH offers the development of dedicated testequipment.
A few examples are listed below
Within the scope of a contract with DFS Deutsche Flugsicherung GmbH we recently performed a comparative performance analysis of the sub-networks that are being developed in support of the Aeronautical Telecommunication Network ATN.
These are the Mode S Subnetwork, the Aeronautical Mobile Satellite Service AMSS and VDL Data Link Modes 2 and 4. Our responsibilities included concept definition, the specification and development of the required test- tools, the development of test scripts and the evaluation of test result data.
At the time that the test campaign was initiated the sub-networks had been functionally verified in great detail. However knowledge of their operational performance was insufficient and it was our task to create a test campaign that provided the missing information.
An essential element of the test campaign was the development of the Data Link Processing Analyser.
This tool facilitated the measurement of the parameters of each data link in a uniform manner, so providing truly comparable test results. The test result data obtained in a combination of laboratory and flight trials was analysed using our purpose-built software tools and summarised graphically. In this way we made a significant contribution to our customer's assessment report.
In the course of this contract we contributed our expertise in the performance testing of data links.
At the same time we obtained an in-depth knowledge of the properties of the data links themselves.