OPAL OLDI (On-Line Data Interchange Standard) Protocol Evaluation

All 1997 reports


This note describes the results of a simulation study about the OLDI protocol as defined by EUROCONTROL. It evaluates the OLDI standard by simulation of the existing procedures and consideration of environmental conditions.

The protocol is run between two ACC's which each consist of a controller (ATCo), a sector flight data server (SFDS) and an OLDI protocol handler. The data flow and the maintenance of the local data bases are investigated under real-time conditions.

The simulation is implemented in SDL and C language using the tool ObjectGEODE extended by the EaSySim II environment.

An analysis is performed on the consistency of the protocol procedures and the timed information exchange. Results are documented by Message Sequence Charts, generated protocol sequences and derived statistical figures.

The study also assesses the feasibility of an automated execution of the OLDI protocol and the usefulness of the applied method and tool environment in the area of air traffic control.

The results show that the defined protocol is correct from a logical and static, ATC operations point of view, but not from a dynamic point regarding execution of the protocol in a real environment under real timing conditions. A number of potential conflicts have been identified which may occur when the protocol is executed in a distributed environment. These problems can be prevented by introduction of additional rules.
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Gerlich, R.

Issue date

June, 1997




on-line data interchange standard, OLDI, protocol simulation and validation, conflict identification and evaluation, performance impacts, distributed data bases


EEC Technical/Scientific Report No. 1997-022

Also known as

EEC Note 1997/16
Last validation: 16/09/2008