The Southern Cross Cable system suffered an outage on the Sydney-Auckland leg this morning after a wavelength switching platform software upgrade at the Alexandria landing station went wrong.
The fault temporarily halted traffic between Australia and New Zealand for one backbone provider, which called the lack of notification from Southern Cross about the upgrade as "simply unacceptable".
The provider told the Australian Network Operators Group that the fault was caused by "an unauthorised and un-notified software change to their wavelength switching platform at Alexandria".
Southern Cross Cable System media director Ross Pfeffer confirmed there was an outage. He said it lasted seventy minutes, and affected four customers.
"It was not catastrophic and there was no smoke or explosions," Pfeffer said of the outage, which he attributed to a software glitch affecting ten percent of the cable system's capacity.
"The work was authorised and planned as part of an upgrade of the network to increase the capacity on the cable," he said.
Southern Cross is currently upgrading its cable system from 10Gbps per wavelength to 40 and 100Gbps, through US company Ciena.
Only Australian customers were affected by the fault, Pfeffer said. The switch has now been reverted back to its original software.
He dismissed comments from New Zealand opposition communications and IT spokesperson Clare Curran, who described the outage as "a catastrophic failure" as "misleading and inaccurate".
Curran urged the NZ government to urgently address the reliance of international connectivity across a single cable, and to provide a full assessment of the risks the country faces if it fails.
The outage didn't appear to affect New Zealand providers, with the chief executive of Snap Internet, Mark Petrie, indicating Snap had purchased fully protected capacity on the Southern Cross.
"It is unusual that two out of three diverse routes failed at the same time," Petrie noted, adding "there is always a possibility of human error causing problems like seen today".
Petrie said while the Southern Cross redundant figure of eight design worked as expected to prevent disruption for providers, a second cable system would be welcome to provide further resilience and route diversity.