Hi Barry, thanks for your comments, and for pointing out that the tone of my post may not have been as I had intended. My message to DN was constructive, it was not intended to challenge anyone's credibility. That's too strong a word. I went to some measure to convey a different spirit, perhaps I didn't go far enough, but I was not attempting to discredit DN, per se, intentionally. Apologies are in order to DN if that's what was interpreted by anyone.
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Re: strain, I don't know what the climate and the ocean currents are at those depths, especially between ridges in the mountain ranges, or how constant they may be. I would imagine, however, that getting cable down to ocean floor levels in valleys, especially at the midpoint between NA and Europe where the mountain ridges are most pronounced, might get to be an undertaking in itself, where peaks are many and the distances between them 'relatively' short.
Also, the ocean floor itself may not always be the most predictable of environments, much less hospitable to outside visitors who plan to stay a while, especially in those mountainous and volcanic ranges where volatility and stress are constant.
I am not going to suggest that the following passage corroborates any of these points of view, or notions, and that's what much of these ares, notions, some of which are based on second-hand information, but regard it for what it is worth, and you can draw your own inferences, accordingly:
From: globalcomms.co.uk
"...plotting a secure route under the sea is no easy task. Aside from innumerable man-made hazards in shallower waters, deep ocean terrain has a surprising share of ‘Grand Canyons' and Himalayan-scale mountain ranges, not to mention hundreds of volcanoes and regions where devastating earthquakes are common. If cables are to survive, all of these features need to be avoided....The sea covers approximately 70 per cent of the planet's surface with over 80 per cent of it being more than 3,000 metres deep. This all goes to make the business of marine route engineering and cable installation a challenging and technical business, highly reliant on accurate surveying, navigation and seamanship.
"Although some areas of the sea floor have been surveyed and mapped in detail, more is known about the surface of the moon than the deep ocean bed. Even when the cable has been laid successfully to plan, so called ‘natural' disasters can occur..."
Again, I would hardly hold this up as a proof, one way or the other, but it does highlight some interesting conditions which are known to exist.
It's been difficult, historically, to get information on this subject, especially at the actual job level, although more is being written about it recently due to the heightened awareness and the increased activity in this space.
Much of my own personal recall about this topic derives from shop talk and what could possibly be construed as folk lore-ish accounts of the laying of earlier cables in the Atlantic, and I may be wrong with regards to the ones which constitute the AC's, and others, which have been placed more recently. So, I would likewise be very agreeable to some definitive level of clarification, and correction, where warranted.
I was asking DN to check these issues out further, while I myself admittedly was implying that other explanations were possible. I asked what references were used in coming up with this knowledge. I didn't come right and say it, instead I softened it by stating that I thought some of DN's accounts were incorrect.
Re: self healing, DN didn't state "self heal," you are correct. Instead, self healing was implied in words that could only mean self heal from inferences made through popular associations, and that's why sought to clarify the notion, while at the same time using the qualifying term, "imply," in characterizing this inference in the upstream post which I was alluding to.
IMO, the general directions of each of the issues mentioned by DN were credible ones, no doubt, and they constitute some very popular notions as to what is taking place "down there" and on shore. I was asking for clarifications, and pointing out the differences between what was being "implied" to be a fast ring restoral, vs what I perceive to be a more involved set processes than what is achievable in a more controlled terrestrial venue, as would be supported by a single carrier, or closely coordinated co-carrier combination.
[[To highlight this point a bit further, we recently had a discussion here, or it might have been somewhere else on SI, concerning an Internet backbone and peering provider's (I believe it as Above.net who lost an OC-3 in the process) who, after a terrestrial fiber break here in the states, found themselves sending packets to Europe and back. I believe the trace routes showed Denmark IP addresses in them, in order to get domestic end points talking to one another again, since their IP trunk routes which were on linear SONET pipes did not self heal. And I suspect that this was the case because those routes were never intended to, nor were they billed as, self healing in the classical <50 msec sense. More likely, they were governed by a more manually intensive, or at best DACS controlled, administration plan of recovery, predicated on the crieteria I mentioned in my last post.
Again, my apologies to DN if my comments were viewed as discrediting, on a personal level. I, too, welcome corrections here, and further comment, since much of what I've stated here is based on assumptions and inferences, as well.
Regards, Frank Coluccio |
