Wolfgang Hummel works as a consultant and solution architect since 22 years at Hewlett-Packard with engagements in all industries. Since multiple years he is working for mobile and fixed line operators where he deployed large scale messaging and voicemail systems. The software used in the projects is a mixture of open and closed source. All software is heavily load & stability tested before rollout to a customer. OpenLDAP is typically a key component for subscriber profile repositories and configuration data. The author was running first tests with OpenLDAP in 2001 and had first deployments of OpenLDAP in 2005.