On NANOG are reports of yet another submarine cable in the middle east that was damaged Sunday. It's a cable between Haloul, Qatar and Das, United Arab Emirates.

Also interesting is that Egypt claims no ship were near two of the previous cable cuts.

• AFP: 4th cut
• 3rd cut ISC dairy
• Egypt investigation article into the first two cuts

Now even in the face of this many concurrent submarine cable losses, most will still have (reduced) service, so it's not a reason to panic just yet. See a.o. the renesys blog for reasons not to jump to conclusions too fast.

Still designing for a quadruple failure isn't the most trivial nor economical solution in all cases, especially not when dealing with expensive submarine links.

Submarine cables are essential for the Internet traffic as they are low latency. Geostationary satellites induce -due to the distance they must be at- significant additional delay on the packets, causing trouble for interactive work over those links.

It's a good reminder for those of us who "only" account for double failures when designing systems and networks.

A good question to pose yourself for business critical applications: what if we had a quadruple failure?
It's a good mental exercise for verifying and potentially enhancing your Business Continuity Plan (BCP) and your Disaster Recovery Plan (DRP). Still keep in mind designing for this level of failures in unused capacity (redundancy) will have significant costs associated with it.

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Swa Frantzen -- Gorilla Security