North American Network Operators Group Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical Re: Cascading Failures Could Crash the Global Internet
I believe the comments about heterogenous networks has to do with a measurement called assortivitiy that is used in statistical mechanics. A homogenous network is when nodes connect preferentially to nodes like them. In a heterogenous network they connect to nodes that are not like them. For networks like the Intneret and the electric grid it is measured by the number of connections a node has. The kicker, that the author's are alluding to, is that the more heterogenous a network is the more vulnerable it is to targeted attack. By taking out a highly connected node - lots of poorly connected nodes that use it as a hub are lost. The AS network had the highest heterogenous score of real-world tested networks, so lots of folks on that bandwagon. That said I don't think the tolerance parameter they set up in the paper makes much sense when applied to the Internet at the AS level. Basically it says once traffic exceeds a certain threshold the node will fail and cause cascades across the network. You guys are the experts but that does not sound overly realistic. ----- Original Message ----- From: Douglas Denault <[email protected]> Date: Saturday, February 8, 2003 7:31 am Subject: Re: Cascading Failures Could Crash the Global Internet > > The model proposed makes several assumptions. My question is about: > > Many real-world networks are heterogeneous and as such are > expected to > undergo large-scale cascades if some vital nodes are attacked. > > on page 3. I do not get the basis for this assumption. So any help > for a 60's > educated math major would be appreciated. > > > On Thu, 6 Feb 2003 [email protected] wrote: > > > > > The paper is avaibable on the Los Alamos site free of charge: > > > > http://xxx.lanl.gov/PS_cache/cond-mat/pdf/0301/0301086.pdf > > > > > > > > ----- Original Message ----- > > From: Sean Donelan <[email protected]> > > Date: Thursday, February 6, 2003 12:43 pm > > Subject: Cascading Failures Could Crash the Global Internet > > > > > > > > > > > Sigh, there are differences between tightly coupled networks, > such as > > > the electric power grid and loosely couple networks like the > > Internet. > > > But there are also some similarities, such as electric grids > use DC > > > interconnections to limit how far AC disturbances propagate; the > > > Internet uses AS interconnections to limit IGP disturbances from > > > propagating. > > > > > > http://sci.newsfactor.com/perl/story/20686.html > > > > > > The actual article requires payment to read > > > http://ojps.aip.org/getabs/servlet/GetabsServlet? > > prog=normal&id=PLEEE8000066000006065102000001&idtype=cvips&gifs=Yes > > > > > > > > > > > > > _____ > Douglas Denault > [email protected] > Voice: 301-469-8766 > Fax: 301-469-0601 > > >
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