SYDNEY--Telstra said a recent outage that disrupted payments systems, transport networks and calls to emergency services was largely caused by its failure to sufficiently recognize the importance of timing consistency across its mobile network.
Australia's largest telco on Wednesday published external investigators' report into July's outage. The investigators, Technology Audit Partners, found failings including in system architecture, oversight and management.
"TAP found the outage was primarily a result of us not treating network timing as a critical capability within the network requiring the highest levels of oversight and protection," Telstra said.
The TAP report said the outage stemmed from routine maintenance at a Melbourne telephone exchange in the early hours of July 8.
Workers restarted a hardware chassis containing equipment that helps keep time across the network. However, the global-positioning satellite card inside it had not been properly updated.
The card reset and began telling other parts of the system that it was 2006, which led to them behaving incorrectly and caused network failures from about 4am local time.
TAP said maintenance and changes since 2020 had degraded Telstra's ability to monitor, control and recognize the importance of network timing.
Telstra said the cause identified by TAP chimed with its statements during and after the outage.
At the time, Telstra said intermittent outages had been caused by server problems at company-owned data centers in Sydney and Melbourne.
Australia's communications watchdog and a panel of lawmakers have launched investigations into the outage.
The watchdog is already suing Telstra's largest rival, Singapore Telecommunications-owned Optus, over its failure to provide emergency-call access during a network outage.
The Australian Communications and Media Authority commenced proceedings in the country's Federal Court in July, alleging that Optus breached its legal obligations on 1,005 occasions during a September 2025 outage.
The rules that Optus allegedly breached are the same as those that it breached in 2023 during a nationwide outage. Optus was fined 12 million Australian dollars, equivalent to US$8.6 million, by ACMA over those breaches.
