Fiber cut?

Tue Apr 22 05:40:28 UTC 2003

On Mon, 21 Apr 2003, Steve Gibbard wrote:
> This is NANOG, and this is pretty basic, so this is probably the wrong
> forum for this explanation.  That said, if a small ISP gets taken off line
> by a fiber cut, it's far more likely to be somewhere between the major
> backbone and the ISP (a circuit which from the ISP's perspective may be
> controlled by the major backbone), than it is that the fiber cut will
> actually isolate the major backbone's POP.  The major backbones at this
> point have a fair amount of redundancy built in, while the circuit from
> the major backbone to the ISP is likely to be a single circuit on a single
> path.
>
> Still, even in that environment, most circuit outages are not fiber cuts.

There are no reliable public statistics concerning outage causes for IP
networks.  The FCC and NRIC have a focus group establishing a voluntary
outage reporting process for Cable, IP and Wireless providers.  See
http://www.nric.org/

Last quarter 49% of all FCC reported outages were facility failures (cable
cuts and similar outside plant problems).  Other sources of outages were
Signalling (21%), CO Power (12%), Local switch (12%) and Tandem switch (6%).