3 ms·
The stability of it is the giveaway. It's not a meta-stable failure state, it's a fully stable failure state. There is positive feedback; increased latency on
by msandford 12y ago
The stability of it is the giveaway. It's not a meta-stable failure state, it's a fully stable failure state. There is positive feedback; increased latency on a link begets further link usage; which causes more latency, etc.
Had there been some kind of negative feedback (in the electrical engineering sense of the word) and this still happened somehow it might be a lot more difficult to track down. But introducing negative feedback is what they did to solve the problem, so perhaps it wouldn't have still happened.
http://en.wikipedia.org/wiki/Feedback http://en.wikipedia.org/wiki/Feedback
- ngbronson 12y agoMetastability comes in when you think about the problem that originally triggered congestion. A normal network overload caused by a bulk transfer, for example, can be fixed by canceling the transfer. Once you add the feedback loop, however, you need to both cancel the transfer and remove lots of other load. I use the term metastable because although it is fully stable (that's the problem!) it isn't the "ground state". Another way to say it is that the metastable states are only local attractors.