Interesting explanation about what really went wrong with Optus last week.
The short version: it looks like Optus doesn’t control its own core network. Its parent company Singapore Telecom does. Optus just resells it.
Which is why Optus’ CEO was so vague about what the issue actually was: she was protecting her bosses in Singapore.
I suspected this was the case the moment I heard about it and the length of time it took to fix it. Typical outage for stuff managed out of SE Asia.