Some of the original f-o submarine cables have consisted of surprisingly few strands, sometimes as few as only four to eight strands, not pairs. That would be 2 to 4 pairs, maybe with two thrown in for maintenance purposes.
Newer constructions have had as many as four working pairs (8 strands) up and operating at one time, using multiple fibers in DWDM configurations. In addition to these, there are usually a couple of strands reserved as spares.
I surmise, without knowing the specifics of GBLX's most recent implementations, their newer constructions still consist of fewer than a dozen individual strands per placement. A pair (two active strands) in each direction at first (with one strand in each direction for working, and one for hot standby), and two strands being used for maintenance and order wire purposes.
The maintenance strands can also assist during times of ring conversions, that is, when they convert from straightaway (point-to-point topologies) to the self-healing ring mode, when the time is right. The time is right when both major legs, or arcs, of the ring are in place. They will usually fire up one leg at a time, upon completion of the first, to optimize usage and revenue potential.
These quantities (which I'm guessing at, where GBLX is concerned) would consume roughly half of the overall potential of the cable, from a physical strand standpoint.
Unless I'm drastically off in my assumptions, I suspect that if I'm erring here, it's probably on the side of too many, and not too few, strands. On the outside, I don't see more that 12 to 18 strands, or 6 to 9 pairs, being laid at this time.
Anyone else? |
