At the end of June 2013, Telstra had 15.1M mobile subscribers in Australia. Telstra Global, the sister company for international operations, is using Diameter signaling technology from Tekelec (see "Telstra Global Uses Tekelec to Manage LTE Roaming") - here.
David Robertson [pictured], Director Transport and Routing Engineering, Telstra says: "Networks are evolving from narrowband signaling to diameter signaling, and we are leading the adoption of this new signaling architecture. DSC provides a more resilient mobile broadband network. We are deploying this technology to ensure we are ahead of the curve with growth in traffic complexity while delivering superior network performance to our customers".
See "Telstra selects Ericsson Diameter Signaling Controller to meet smartphone growth" - here.