Fiber Optic cable is the most suitable option to connect data network among islands and countries due to the high bandwidth capacity. Fiber optic network can be installed in the land and undersea. Sub marine  cable recovery / problem solving when broken is more difficult than in the land. It is a big challenge!

Submarine cable could be cut or broken due to earthquake, hit by whale or fishing gears, etc. In this situation, the cable ship is urgently dispatched to the cable failure site and repairs the cable.
The cable repair procedure normally consists of the followings:
1) Localization of the cable failure point.
2) Recovery of the failure cable onto the ship
3) Cutting and removal of the cable failure section
4) Jointing of the recovered cable and the spare cable in the cable tank of the ship
5) Confirmation test and reburial of the cable

The difficult thing of this repair processes is localization of the cable failure point. When cable cut then each side of cable will be separated by wave of ocean. The level of difficulty will increase when the ocean currents get heavier and the ocean deeper.

Repairing it needs very high cost to operate the ship, seeking the cable, & recover the damage.