The Hengchun Earthquake : A Flashback to the Networking Disaster

On one side, it is no doubt that network reliability is important. But on the other side, "important" is something that can be understood differently. Thus, network reliability might be implemented variously according to some tradeoffs. What portion given to reliability aspects depends on the owners' strategy and policy. Let's consider an example.



A powerful earthquake of 7.1 magnitude happened on 26th December 2006, shaking the seabed off southern Taiwan. 9 submarine cables in the strait of Luzon between Taiwan and the Philippines were broken, disrupting communications to/from several asian countries to the rest of the world via those regional/trans-pacific cables. As of 2007, at least 16 submarine cables are laid on the seabed of the Luzon strait; why do so many systems have paths through this region ? is there no other possibility to connect SE Asia to the US ? Hmm.

What were the impacts of this earthquake? Yes, sure :-D the Internet in Asia stopped ! According to ANC:

• Taiwan, Hong Kong, China (total daily GDP = USD 7.56 bn) went offline ... as did most of South (East) Asia
• Google, Yahoo, MSN (total daily revenue = USD 53.4 mn) became unreachable from much of Asia (of significant traffic originators!)

• Estimated total bandwidth impacted 600+ Gbps
• Estimated total Internet capacity impacted 500+ Gbps

The role of telecommunication and the Internet is nowadays almost not replaceable. Such a disastrous event would affect day-to-day (business) activities such as financial markets (incl. banking, commerce, airline bookings etc.) and general communications (e.g. voice, email, web etc.). In the above case, even with the rerouting through undamaged cables, delays were experienced in the following weeks. It took 11 ships 49 days to restore everything back to normal. This was due to the number of faults, the availability of cable repair vessels, adverse sea conditions, the occurance of faults in water depths down to 4000m and the burial of some cables under a layer of mud.

The following cable systems were affected by the Hengchun earthquake (totally 21 faults were recorded in 9 cables):

• C2C : 2 major breaks (S2/5)
• APCN : 2 major breaks (sB5/B17)
• APCN2 : 2 major breaks (s3/7)
• SMW3 : 3 major breaks
• EAC : 1 minor break
• ...