Same with Libya. How did these countries’ dictators cut off the internet?
I know that for some countries, or if you look at the “map of the internet” (just a map of connections) bundle into a few strands- China has this power, as the gov’t controls all major junction, Egypt convers several juntions (of course if those were cut, the entire continent could lose internet- the Suez area is very critical.
Also, with Egypt having a few (I think 4) ISPs, you can cut those- most nations (USA being one of the not following this) only have 1 or 2 major connection points- typically the DNS and such are located in the capitol, or are only 1 point- so its easy to cut 1 main point.
In the Third World, all telecommunications are expected to be government monopoly. Many Third World autarkists believe that allowing it to fall into private hands will result in some Deus Ex style dystopia in which Illuminatist Bob Page controlled all telecommunications networks on earth.
When telecommunications were partially privatized in India, many people of the “homespun cloth” crowd objected to it, even though the same have also protested government controls on media and attacks on civil liberties. I don’t know, they want a world where government owns the media but does not control it? Does it make sense to even them?
Dudes with guns went to an ISP HQ, talked to the boss’s boss and told the IT geeks to settle down or expect talk talk from the Dudes with guns. So, they obey and cut the off access pure and simple.
They have smaller infrastructures than western countries. For example the USA has 7 tier 1 ISPs each with several international connections. That would be very difficult to shut off and especically when you have tier 1 isp’s that are not american within the united states and are providing international connections. It is possible however. Most likely way a government would shut off the internets is by disabling services at the ISP. Within egypt they probably have a one or two isps that control several interational links. I would guess they would do something on the isp side so that all the users stay synced (dsl) but they can’t resolve any ips or dns.
A rogue hub router could be set up to reconnect the system, though ultimately the transmission cables could be cut.
Kinda, you will need cooperation from neighboring network providers, and internal pirate networks to advertise and update an alternative BGP routing table for the country. Then, the propogation of the newly updated global BGP table would still take a long while to update globally(days). Anyone caught adjusting thier return routes, from within the country, will obviously get in some serious trouble, and it wouldn’t be hard to figure out who. 
Theoretically you could run the whole thing on wireless and satellites, but so far we rely on fiber optic cables for the vast majority of our data transmission.
The only problem I see with just cutting the cables out- as it is a lot easier to lay marine cables than pull it through a desert, is that this only isolates the network- to kill intra-network activity, there would be a lot more cables, to me an impossible number to cut, compared to just cutting off the ISP and DNS service.
“to kill intra-network activity, there would be a lot more cables”
that’s the thing that someone else barely touched on…
in order for your browser to work, you need to hit the server that converts the address to the actual server. I believe this is called th DNS. Domain Name Server. I’m not sure, but I believe there might only be a few or maybe just one. If they cut access to that server, your browser will not work.
It will still work. DNS is mostly only for convenience to us humans. When DNS is down if you know ip of website you will still connect to it without a problem. Thats why when you check if your connection is working you should ping an IP adress instead of DNS one. Still DNS is weak point in generally solid internet architecture - it is centralized.
I think Libya just reset the router and changed the password…
DNS is like one of the easiest things to replace. The difficult part, as I said above, will be restructuring the internet’s routing table via BGP, while not getting your internal pirate network dudes in trouble.