Re: Self healing, Diversity-Redundancy, Submarine FO Splicing
                      Dave, thanks for bailing me out with undersea-related questions which are                      consistent with those from Dennis. The edit timer creamed me when I was                      about to add some language about the use of cameras, electronic locator                      methods, remote operated vehicles (ROVs), etc. 
                      To answer your last question first, in shallow water closest to the landing                      point, double armor is used. The thickness and number of layers of armor                      tapers gradually width ocean depth. Don't know for sure if this aids in the                      location process, but it makes sense if electronic means are being                      employed. There was once a problem with the emissions being sent out                      from fiber optic cables attracting sharks. Don't recall if they were                      ultrasonic waves, or what, but the sharks had a field day chewing up the                      armor, and through to the fiber in some cases, causing major failures to                      occur. Anyone recall this, and what the fix was?                     ---                     "Self-healing: Is that to say that it's self-healing to nicks and scrapes,                      but not to limb-severing wounds?"
                      Yes. If the limbs in your analogy happen to be Digital Cross Connects                      and classical switching machines, and the scrapes and nicks happen to be                      fiber breaks and SONET nodes.                     ---
                      "Geographic diversity of the cable routes... by some distance greater                      than the bucket width of a backhoe... and preferably many miles.. is the                      only way to achieve this, correct?"
                      End to end geographic diversity, with no crossovers anywhere along the                      way. That one exception is probably due to a main central  manhole                      somewhere that has all the activity in it. It will get you every time. |