shields@crosslink.NET (Michael Shields) writes:

You'd also want to look at more than just the count of outage reports;

the size of the outages matters, the total size of the network, and

the MTTR. If you "had to" distill it to a single number I suppose

percentage uptime is the one to use.

The problem with percentage uptime is the law of large numbers.

You need a huge disruption affecting a lot of customers for a long

time to move the uptime percentage. As a customer I don't really

care how much everyone else circuits were up. I only care about

how much my circuits are up. If my AT&T circuit is down, it doesn't

matter to me that 99.99999999999999999% of all AT&T's other circuits

are working.

I'm not sure fiber cuts are common enough to make a meaningful

statement about the reliability of one carrier vs. another.

I agree. The initial fiber cut isn't that meaningful. I have no

hypothesis why backhoes (or other natural hazards) would prefer

one carrier's fiber over another carrier's fiber. WilTel's initial

plan of putting fiber inside steel gas pipelines not withstanding.

Hence my original statement that there is no difference between the

carriers based on just fiber cuts. Its like calculating the probability

of a coin flip, just because one carrier had fewer fiber cuts this year

doesn't seem to be a good predictor how many fiber cuts they will have

next year.

But how the carrier reacts after the fiber cut is an area you can

make statements about the differences between one carrier vs. another.