A case study of dependable software upgrade with distributed components

The technology presented allows validation of software architecture before component upgrades. This paper presents a case study of applying this method to the upgrade of a wireless monitoring system. After the validation showing the feasibility for an online upgrade, an actual upgrade was carried out and proven to be successful. A wireless monitoring system collects network data to deduce voice quality of voice-over-IP (VoIP) and notifies wireless users of network failures. Voice networks traditionally operate with an availability of 99.999%. Software upgrade must be done online to maintain such a high availability. Our experimental results show that the outcome of the actual upgrade is consistent with the validation result of the method given by Li et al. (2000). Our method is effective in providing round-the-clock wireless network activities while upgrading network protocols or application software.