Another way to cripple the internet on a more regional basis is that most national and international data travels through specific cable networks.
So in Ireland for instance the backbone fibre lines are owned by 3 or 4 entities (it has been a long time since I checked) and they are linked at specific physical locations where they also link to the international cables.
The same occurs in other countries. So if one identifies these interchanges and target them physically you break up the national internet in a country in isolated minor networks.
Similar weaknesses exist in the power grid and the power grid is attackable via software.
It should also be noted that cell phones are capable of mesh networking. That is, in the absence of a cell tower in range a phone could pass messages to another nearby phone, which passes that on to another until an active cell tower is reached. Currently telecom companies have that functionality shut off but people worried about natural disasters have been pushing governments to mandate that telecom companies enable such features to function in a disaster scenario.
It may have got some traction in California, though I am not sure if it yet law. So you may want to consider that in your scenario.
So in Ireland for instance the backbone fibre lines are owned by 3 or 4 entities (it has been a long time since I checked) and they are linked at specific physical locations where they also link to the international cables.
The same occurs in other countries. So if one identifies these interchanges and target them physically you break up the national internet in a country in isolated minor networks.
Similar weaknesses exist in the power grid and the power grid is attackable via software.
It should also be noted that cell phones are capable of mesh networking. That is, in the absence of a cell tower in range a phone could pass messages to another nearby phone, which passes that on to another until an active cell tower is reached. Currently telecom companies have that functionality shut off but people worried about natural disasters have been pushing governments to mandate that telecom companies enable such features to function in a disaster scenario.
It may have got some traction in California, though I am not sure if it yet law. So you may want to consider that in your scenario.