SINGAPORE – Singtel said the upgrading of the Singtel Internet Exchange’s (STiX) software was not the root cause of the Optus network outage on Nov 8.

STiX is Singtel’s Internet peering exchange, acting as an infrastructure “shortcut” that helps move vast amounts of data across the world.

“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 fail-safes,” the largest telecommunications operator in Singapore said on Thursday, noting that STiX is one of Optus’ international networks connecting to the global Internet.

“However, the upgrade was not the root cause.”

The company referred to recent media reports indicating that “changes to routing information” from STiX, following a routine upgrade, led to Singtel-owned Optus’ 14-hour-long network meltdown last week.

The outage was first reported at about 4am in Australia on Nov 8 (1am Singapore time).

Singtel said the upgrade to one of STiX’s routers was planned for 1am Singapore time on Nov 8. The company had given prior notice to all affected customers, including Optus and other telecoms companies.

“During the upgrade, data traffic was routed to other points of presence on the STiX network, and back into customers’ networks,” said Singtel.

“The STiX upgrade was completed within 20 minutes, and all its customers’ routers that were connected to it, including Optus’, were up and running,” it added, noting that network resilience and security remain a top priority of the group. “Singtel will support Optus as it learns from what has occurred and continues to improve.”

Singtel shares fell as much as 5.2 per cent to $2.35 on Nov 8, following the news of Optus’ network outage.

More than 10 million Australians were hit by the blackout, triggering fury and frustration among customers, and raising wider concerns about the telecoms infrastructure.

Singtel shares closed flat at $2.38 on Thursday. THE BUSINESS TIMES