Too Many Connections Weaken Networks

itwbennett writes "Conventional wisdom holds that more connections make networks more resilient, but a team of mathematicians at UC Davis have found that that is only true up to a point. The team built a model to determine the ideal number of cross-network connections. 'There are some benefits to opening connections to another network. When your network is under stress, the neighboring network can help you out. But in some cases, the neighboring network can be volatile and make your problems worse. There is a trade-off,' said researcher Charles Brummit. 'We are trying to measure this trade-off and find what amount of interdependence among different networks would minimize the risk of large, spreading failures.' Brummitt's team published its work (PDF) in the Proceedings of The National Academies of Science."

Comments

Primitive

[gilgongo]

I'm sure that in 100 years time, people will look back on our understanding of networks, information and culture in the same way as we look back on people's understanding of the body's nervous or endocrine systems 100 before now. This study hints at our lack of knowledge about what the hell is happening.

Re:Primitive

[gl4ss]

the study was about power grids, where it makes a bit more sense. of course in that context(and in data-networks, though with data it actually matters where a certain data packet goes as data consumers don't just want _any_ data, they need specific data, but power you don't much care where it actually came from..).

still, gotta wonder, in real world context you'd need to think about what kind of real mechanisms are used for making the new connections and safeties supposed to stop cascades from spreading.

Re:Primitive

[Anonymous Coward]

Cascades on power networks happen when you suddenly lose source, without rejecting the drain. I.e. the load remains high, but suddenly the flow required to supply that load has to shift because a link went down due to failure/overload.

There is a protection against this, it is called selective load rejection. You shut off large groups of customers, plain and simple. And you do it very very fast. Then you reroute the network to make sure power is going to be able to flow over links that will not overload, and do a staggered reconnect of the load you rejected.

That costs BIG $$$$ (in fines, lost revenue, and indirect damage due to brown-outs), and there is a silent war to try to get someone ELSE to reject load instead of your network. The only thing that balances it are extremely steep fines among the power networks themselves, and in countries that are not nasty jokes, the government regulatory body.

I am not exactly sure how to move that to a BGP4, IS-IS or OSPFv2/v3 network, where instead of a sink pressure, you have a source pressure.

Too many cooks....

[bwohlgemuth]

As a telecom geek, I see many people create these vast, incredibly complex networks that end up being more difficult to troubleshoot and manage because they invoke non-standard designs which fail when people wander in and make mundane changes. And then when these links fail, go down for maintenance....surprise, there's no 100% network availability.

Three simple rules to networks...

Simple enough to explain to your grandmother.
Robust enough to handle an idiot walking in and disconnecting something.
Reasonable enough to be able to be maintained by Tier I staffing.