A good analogy (I think) is real borders. In this case airspace borders. What Egypt have done would be the equivalent of saying to it's air controllers "Any pl

A good analogy (I think) is real borders. In this case airspace borders. What Egypt have done would be the equivalent of saying to it's air controllers "Any plane incoming for an Egyptian airport, tell them we don't know where it is." And the only option that plane has is to return home (real analogy: the message gets sent to the source airport and the plane disappears into a black hole). However, any plane that wishes to fly through Egyptian airspace to reach other countries, that's fine, and get's it's routing directions just fine. The alternatives that the article are talking about, closing down the "bottom" routers: close down all the airports, instead of the whole airspace. This has the same effect, but is harder to co-ordinate. A complete border shutdown would be like unplugging the cables... any aircraft flying through the airspace would be blackholed, and aircraft attempting to fly in will be blackholed, any attempting to fly through will be blackholed... all with a polite notice of course. DNS would be equivalent of keeping the airports open & saying "shut down all the screens and don't let any airline attendant tell people the gate that their plane is flying from" (except that are millions of gates...). If you're smart enough to have written it down (cached), or know the gate directly, then you're still going to make your flight. If you don't, you've no chance of making it. (Let's not add vhosts into the mix... okay, maybe for fun... like arriving at the plane, and them saying "this service stops at 100s of destinations, and you've lost your ticket, so we can't let you board").