Optus' safety systems, not routine upgrade, caused outage: SingTel

(Reuters) - Singapore Telecommunications (SingTel), the parent of Australian telecoms provider Optus, said on Thursday a fault in Optus' safety mechanisms, and not a routine software upgrade triggered by SingTel, led to the 12-hour long outage last week.

More than 10 million Australians were hit by the network blackout at the Singapore Telecommunications-owned (SingTel) telecom firm on Nov.8, frustrating customers and raising wider concerns about its telecommunication infrastructure.

SingTel conducts routine software upgrades for its infrastructure through its internet exchange, STiX. Multiple telecom firms including Optus use STiX's international networks that connects to the global internet, the Singaporean telecom giant said.

"We are aware that Optus experienced a network outage after the upgrade when a significant increase in addresses being propagated through their network triggered preset failsafes," SingTel said.

"However, the upgrade was not the root cause," it added.

Optus earlier in the week said an initial investigation found the company's network was affected by "changes to routing information from an international peering network" after a "routine software upgrade".

SingTel's statement comes a day before Optus CEO, Kelly Bayer Rosmarin faces an Australian senate inquiry into the massive outage.

(Reporting by Sameer Manekar in Bengaluru; Editing by Dhanya Ann Thoppil and Nivedita Bhattacharjee)