AFTER years of marvelling at the rapid changes the Internet has wrought on the global economy, the world was painfully reminded this week of how reliant it is on the fragile strands of fibre-optic cable lying deep down on the seabed.

Cables from at least six major undersea networks carrying the phone calls and e-mail of millions of Asian users were damaged by the Taiwan quake late on Tuesday.

As connections went down, suddenly everyone - from brokers to eBay traders - did not feel so secure any more in the idea of being able to work anywhere at any time.

So far, it is unclear how much money has been lost.

For currency traders in Seoul, failing to communicate with Singapore and Hong Kong could mean a painful cut in the US$1.5 billion (S$2.3 billion) they transact daily in spot trading on the Korean won.

As things begin to go back to normal this week, what should people make of the situation? The dependence of Asian economies on closely linked undersea cables is clear.

When a big earthquake hits Taiwan, the undersea cables around it that carry traffic from many Asian countries to the United States are affected.

But should people see these undersea cables, which have to endure not just the occasional earthquake, but also anchors dropped from fishing boats and curious nibbles from sharks, as the weakest link?

Or should they marvel at the quick recovery - many users were able to get back online yesterday - that the Internet is said to be built for?

Experts are divided. Some, like Mr Frank Dzubeck, president of US-based telecoms consultancy Communications Networks Architects, say that Asian economies should not rely on cables laid so close to earthquake zones.

The argument goes that there should be more cyber highways laid directly to the US, instead of going through Japan and Taiwan.

On the other hand, some telcos ask: Would anyone need two CTEs if the existing one was not affected by major jams caused by serious car breakdowns every day?

Telecoms executives say that cyber highways - like roads - should follow the business. That is, the routes should link up as many countries as possible, so that the billions of dollars invested in the cables can be fully utilised.

Asia Netcom's president Wilfred Kwan told The Straits Times: 'Taiwan and Japan are in the earthquake zone. Should we avoid those countries? I don't think so.'

His company runs the East Asia Crossing undersea network, which was relatively unscathed, and is now taking on Internet traffic from other affected networks.

He said: 'I don't think you can stop an earthquake from happening. But you can limit the damage.'

This is one point that everyone seems to agree on. There should be adequate back-up, in case a similar earthquake hits again.

But nobody knows exactly how much back-up is enough. Right now, telcos are already using several different networks to connect overseas.

StarHub, for example, has links not just to East Asia Crossing but to almost all the major cables in the region. Yet it was hit by the downtime.

SingTel co-owns several cable networks in the region, which would seem to guarantee that it would not be cut off totally if one of them was disrupted.

Yet, SingTel also got hit. Four of its cable networks were damaged in the quake, so it had to divert some of the traffic over land and via satellite.

Right now, the best bet seems to be to react fast to any problems, say telcos. In Singapore, at least, most users here were able to surf the Net yesterday, though some e-mail messages were not delivered.

The good news is that India, Asia's outsourcing hub in the west, was not hit hard this time.

But India will do well to learn how to recover from an info blackout. After all, how can call centre staff in India help a customer if he is unable to answer calls?