I wouldn't say it's weird. We used to use CPU-bound proof-of-work, so network-bound one is just not so familiar.
Not just "not so familiar", it has completely different properties.
Your hashing power depends only on what you do. I.e. you need to buy certain hashing device, then pay for electricity. Costs are well understood, and you get stable hash rate if your hardware works.
But network bandwidth's nature is very different: it, by definition, depends on your interactions with whole network.
It's impossible to receive and transmit data at faster rate than allowed by a channel throughput.
It isn't enough to buy channel to some peer, as peer might not want to relay your traffic at full channel bandwidth.
Costs depend greatly on who you are:
- For tier 1 networks bandwidth is usually free, they don't pay for peering. So for them it is about costs of creating channels, after that traffic is essentially free
- Smaller networks might need to pay for peering, but they can get some free traffic on traffic exchanges and whatnot.
- Commercial users often pay a lot for bandwidth they use. Unless they can find some wholesale deal. Wholesale bandwidth is much cheaper than regular price you can get from ISP, but you have to commit to some minimum. This is how things like imgur.com and sendbigfiles.com are possible. Just one shitty image on imgur can easily generate 100 GB traffic, but apparently they have fat pipes...
- Residential user often pay a tiny sum for considerable bandwidth, but it depends on where you live. Essentially, ISPs think that even if you have 50 Mbit/s connection, you'll be using a tiny fraction of it on average. Some ISPs throttle heavy users...
So traffic price might change 1000-fold depending on who you are, where you are and how you're going to use it.
Thus it IS possible to simulate 1000 nodes for costs of just 1 node if you have some sweet deal.
Just like any computer center/cluster can attempt to attack Bitcoin.
Not really the same: attacking Bitcoin has opportunity/electricity costs. While spare bandwidth is essentially free.
ISPs have to cooperate each with other, coz in Qubic nodes r supposed to be distributed randomly around the globe.
Have you ever heard about packet spoofing? Your ISP can pretend to be around the globe.
![Smiley](https://bitcointalk.org/Smileys/default/smiley.gif)
You cannot really check where packets come from geographically.
Attack on Qubic might cost just a couple of bucks. Or billions. It depends on an implementation.
As I said, fundamental cost structure is different.
I think it would be cool to see a protocol where PoW will be augmented with some network-level checks. Essentially, we could isolate asshole miners who block legit transactions, or perform double-spends. I have designed a basic sketch of such implementation, BTW...
But using only "proof-of-bandwidth" seems to be a recipe for disaster: it waste resources just like Bitcoin, but does not provide same security.