Asian undersea cable disruption slows internet access

A segment of the Asia-Pacific Cable Network 2 (APCN2) undersea cable network between China and Taiwan has suffered a serious cable fault, causing internet traffic to be rerouted onto other undersea cables and slowing internet access for some users in Southeast Asia.

At about 10:50 am on Wednesday, Singapore time yesterday, an alarm signaled a cable fault on Segment 7 of APCN2, which connects Hong Kong and Shantou, China. The disruption caused a temporary loss of service on the undersea link but all customers that use the cable were soon shifted to capacity on other cables, according to a source familiar with the situation.

The APCN2 cable is owned by a consortium of 26 telecom operators from 14 different countries. The cable links Singapore, Malaysia, the Philippines, Hong Kong, Taiwan, China, South Korea and Japan.

The exact cause of the APCN2 fault was not immediately known. The alarm indicated the disruption was caused by a "single point of failure," which suggests a variety of possibilities, including a technical failure or a cable cut, the source said. One cause can apparently be ruled out: Taiwan's Central Weather Bureau did not record signs of seismic activity around the time that the alarm was received.

The incident was likely the main reason that Internet access appeared slower for some users in Singapore on Wednesday, the source said.

Undersea cables are used to transport much of the world's internet traffic and can be easily damaged by natural disasters or other causes. In 2006, a powerful earthquake off the southern coast of Taiwan damaged several cables and slowed access to a crawl for users in Southeast Asia.

Singapore Telecommunications (SingTel), which is an investor in APCN2, said its users may experience slower access than normal to some US websites, blaming the APCN2 fault on damage caused by Typhoon Morakot.

"The [APCN2] consortium members have started restoration works, and our engineers are in the process of diverting Internet traffic to other cable systems. We expect the situation to return to acceptable levels within the next 24 hours," SingTel spokesman Chia Boon Chong, said in an e-mail statement.

A spokesman for Starhub, another Singapore ISP that holds a stake in the cable, did not return a phone call seeking comment.

The fault that hit APCN2 on Wednesday follows two other service disruptions that recently hit the network. One disruption affected APCN2 Segment 7, between Hong Kong and Taiwan, and the other affected APCN2 Segment 1, which connects Singapore and Malaysia. However, both of these disruptions were deemed to be "relatively minor" compared to the disruption that took place Wednesday morning, the source said.

The cause of the two earlier faults on APCN2 was not immediately clear.

APCN2 isn't the only Asian undersea cable currently suffering from a service disruption.

"The Cable & Wireless Real Time Operations Team have logged multiple cable breaks on APCN2, APCN, EAC and SMW3 in Asia Pacific — specifically, near Taiwan. Network traffic flow has been adversely affected in and out of the region as a result," said Gavin Tait, director of Asia network planning and implementation at Cable & Wireless, in an email statement provided by the company.

None of Cable & Wireless’ customers were affected by these failures, he said.

Efforts are currently underway to repair the East Asia Crossing (EAC) undersea cable after it experienced "double faults" off the coast of Taiwan last weekend, according to Roland Lim, a spokesman for Pacnet, which owns EAC.

The first sign of damage to the EAC cable off the coast of Taiwan came on August 9 at 1:37 am, local time, when an alarm signalled that service on EAC Segment D, which links Taiwan and Hong Kong, had been disrupted, Pacnet said in an Aug. 10 Network Event Notification that was obtained by IDG News Service. At the time, traffic on Segment D was transferred to EAC Segment C. However, Segment C suffered a second disruption roughly twelve hours later.

The cause of the faults that hit the EAC cable between Hong Kong and Taiwan is not yet known, but the damage happened at about the same time the southern part of the island and China's southern coast was being pummeled by one of the most powerful typhoons to strike in recent memory. There were no earthquakes recorded by Taiwan's Central Weather Bureau at the time when the disruptions took place.