On Sat, 14 Sep 2002 sgorman1@gmu.edu wrote:
The point being from a structural stand point there is convincing empirical evidence that the Internet is not a distributed network.
Due to policy constraints the commercial Internet more closely mimics a collection of decentralized networks. However, things are more complicated because IP permits networks of any size to interconnect a almost any level over almost any communications technology. We normally consider it an error when external traffic transits an intranet or extranet. But during a disaster, capacity is capacity.
a small minority has the vast majority of conections. The applied side of this I think I've posted about before, so please pardon the redundancy, is that Internet as the AS and router level is very resilent to random failures but highly susceptible to targeted failures. This has become so predominant in the literature it has left many folks asking questions along the lines of security.
This has come up on this list and others before. I've previously commented on some of the published papers. I'll try not to repeat everything. The missing piece from most of the previous papers I've read is how do you find out how much unused capacity exists? BGP views and Skitter data is very good at finding used paths, but it tells you nothing about how much "shadow" capacity exists. Generally, after a disaster you'll discover new capacity exists in the Internet which you couldn't detect before the disaster. Where does that capacity come from, and why couldn't you detect it before the disaster? And how much capacity exists in the shadows?
This has led a scramble to come up with new Internet topology generators - another laundry list of references and approaches - but the reported security implications have had a bumpier road. Are all these computer scientist and physicists wrong, I'm sure a good case could be made against them, but it leaves several open questions. There have been several good cases made for the resilence of the statas quo and good arguments that there could be problems. The question is how much of it is political. One side looking for problems they can point fingers at in the name of homeland security and one side denying any problem at all because it is a lot cheaper if there is no problem.
The research community comes up with a model how the Internet works. They hypothesize various outcomes based on that model. The final section of any research report is a list of problems requiring more research :-) The operational community looks at the model, goes behind the curtain and compares the model to their operational networks. We find the model doesn't match. The operational community comes back out from behind the curtain and tells the research community our network doesn't have that problem. And if it did, its fixed now :-) The research community asks can we please peek behind the curtain? The operational community says we respectfully must decline. Rinse. Repeat. I probably won't make it to the next NANOG in Eugene, but on Sunday afternoon NANOG is hosting a research/operation forum to allow researchers to solicit feedback from the operations community. The proposal deadline is Monday, September 16.