On 9/13/2002 at 10:30:47 -0400, alex@yuriev.com said:

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Yet, it is reasonable that people expect x % of their traffic to use IX's. If those IX"s are gone then they will need to find another path, and may need to upgrade alternate paths.

I guess the question is.

At what point does one build redundancy into the network.

No, it doesnt necessarily use IX's, in the event of there being no peered path across an IX traffic will flow from the originator to their upstream "tier1" over a private transit link, then that "tier1" will peer with the destination's upstream "tier1" over a private fat pipe then that will go to the destination via their transit private link.

I'm only aware of a few providers who transit across IX's and I think the consensus is that its a bad thing so it tends to be just small people for whom the cost of the private link is relatively high.

I think you are missing a one critical point - IX in this case is not an exchange. It is a point where lots of providers have lots of gear in a highly congested area. However they connect to each other in that area does not matter.

Now presume those areas are gone (as in compeletely gone). What is the possible impact?

They're all completely gone? Then we have a bigger issue than the Internet not working, because lots of us are dead. A lot of the exchange areas are city-wide, in a literal sense. Take DC, for example. Lots of folks connect in DC, not just at MAE-East, but also via direct cross-connects between providers, following a large variety of fiber paths owned by a variety of carriers. A single event that removed all the connectivity from DC would either have to devastate the city and surrounding suburbs, or at a minimum, distrupt electronics (EMP airburst) or hit every power plant in the area (and yeah, that kills folks, too, especially in winter.) Now, having destroyed civilization in DC (so to speak), we have removed a major exchange point, but also all traffic generated in DC. The rest of the Internet is fine. To break the rest of the exchanges, we'd have to do the same to New York, Dallas, Boston, Chicago, Atlanta, San Francisco, San Jose... And that's just in the States. If you were to hit a telco hotel (usually a hard target, but we'll grant you the necessary firepower), you would inconvenience the Internet in that area until another well-connected site could be chosen and filled with equipment. Internet infrastructure is logically mapped to telco infrastructure, and telco infrastructure is ubiquitous. You're looking for a weakness where it isn't. If you wanted to hurt the Internet, you wouldn't hit a city. You'd hit the cross country fiber paths, out in the middle of nowhere. -Dave