More than 10 million Australians were hit by the 12-hour network blackout at the Singapore Telecommunications-owned (SingTel) telecom firm on Nov. 8, frustrating customers and raising wider concerns about its telecommunication infrastructure. Optus had 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, while confirming that Singtel Internet Exchange (STiX) is one of Optus' international networks that connects to the global internet, denied that the routine software upgrade was the root cause.