Run-time upgradable software in a large real-time telecommunication system

For large real-time systems it is often important to achieve non-stop availability. Software updates must therefore be made during program operation. We consider a number of techniques for run-time software updates, and concentrate on one particular technique called Dynamic C++ Classes that allows run-time updates of C++ programs. The Dynamic C++ Classes approach is evaluated on a large real-time telecommunication system, the Ericsson Billing Gateway. The evaluation showed that there were no significant performance problems generated by the Dynamic C++ Classes approach. We have identified and discussed a number of problems with the approach and we have also implemented some improvements of the approach.