Patrick W. Gilmore wrote:
End of day, an IXP is not some magical thing. It is an ethernet switch allowing multiple networks to exchange traffic more easily than direct interconnection - and that is all it should be. It should not be mission critical. Treating it as such raises the cost, and therefore barrier to entry, which lowers its value.
Exchange points are often located in the same building as a carrier hotel which houses infrastructure for many ISPs and many transit providers. If you consider the internet is used only by teenage males to learn about female anatomy (pictures and movies), then your statement is acceptable. But with the Internet now used for serious applications, the focus point of a carrier hotel and exchange becomes much more mission critical. Ane because it is a focus point, it becomes much harder to have redundancy in the buildings (to provide for disaster tolerance). So the natural avenue is to strenghten/re-inforce your one central building. But availability s measured by the weakest link. You can have a bunker data centre like the one shown in this thread, but if, at the end of the day, all of a city's fibre links to the rest of the world follow the same railway track right of way to exit the city (and cross the same bridges) , then you still have a weak spot and central points of failure.