Tag Archives: cable cut

NANOG: Submarine adopts 40G and 100G

Per Hansen of Ciena at NANOG 50 talked about growing capacity not by adding more data cables under the sea, rather by increasing spectral density. Eventually new cables will be needed, but meanwhile he thinks we can get up from about 2 bits to to 5 or 6 bits per Hertz. It does require more power: same energy per bit, but more bits.

Plus mesh networks for rerouting, even if it means rerouting backwards around the world, he notes. We’ve observed that sort of emergency backwards routing as long ago as January 2008, in the U.A.E. Cable Cut.


Van Meter on Barabasi and Doyle on Internet topology and risks

rdv-hakama-0609.jpg Rodney Van Meter, co-teaching a class by Jun Murai, posts notes on why Albert-László Barabási (ALB) is both right and wrong about the Internet (it is more or less a scale-free network when considered as a network of Autonomous Systems (AS), but contrary to ALB's assumption John Doyle and others have pointed out that the bigger nodes are not central, an AS as a node would be somewhat difficult to take out all at once, there are both higher and lower layer topologies that make the Internet more robust, and the Internet's biggest problem isn't topology at all:

The most serious risks to the Internet are not to individual "nodes" (ASes), but rather stem from the near-monocropping of Internet infrastructure and end nodes, and the vulnerability of the system to human error (and political/economic considerations):

Monoculture, who would have thought it?

For that matter, the Internet's ability to reroute has been very useful to ameliorate topological link breaks at the physical layer, for example undersea cables in the Mediterranean Sea twice last year.