Filtering and media reports - optus PR said nothing...
this is all because their where media reports theorising that the reason they could not get hold of optus was because Executives used only Optus and had no backup
I will tell you all members of rivals firms e.g. Vodafone carry known backup SIM and are instructed to swap to those as part of a BCP (business continuity plan)
I highly doubt it was a "personal" DR strategy they are just trying to either explain away the fact they did and said nothing for HOURS while the whole network was down
(the NOC will have been actioning and running full stream but the execs where shown to be pointless and did not communicate to their customers )
the real issue was while emergency calls (000 / 999 / 911) on GSM roam to whichever network is available and it that works for Optus as they are rarely the only carrier/provider in a area THEY HAD NO BACKUP solution for all their digital/VoIP lines beyond switching to Optus GSM which was also down - this effected HOSPITALS, doctors and trains
Frankly the Australian Government should be looking at how to regulate firms who are not publicly listed in australia and have responsibility to foreign owners
optus network assets and config has clearly been sweated and lack investment
they should have been filtering their routes and at a minimum using RPKI and investing in IPv6 like other ISP's... they did not and wanted as much money sent back to the parent corp as possible
when we see RPKI and IPv6 on the optus network then we will know the engineers have been given the budget and they actually have had the time to fix this mess...
do not trust them beforehand