The amount of hops a chunk takes to reach the recipient is O(log(n)) in a worst case scenario. For example, in a network with 1 million nodes that means about 20 hops. Popular chunks get cached, reducing their hop count, so to take this into account and for the sake of simplicity, let’s say we have a SAFE network with an average chunk hop count of 10.
This means that for every GET of a (1 MB) chunk a vault serves, 10 MB of both up- and download bandwidth is used for routing (by all intermediary vaults), while only 1 MB upload bandwidth is used for actual farming (by the vault that had the chunk). Every vault is expected to route data for it’s position in the DHT, regardless of the size of the vault. This means that the chunk routing burden for a vault is equal to:
H = average hop count
S = average size of a chunk (almost 1 MB)
G = total network-wide GETs per day
C = average amount of copies per chunk (usually 6)
V = amount of vaults in the network
Daily vault routing burden = (H * S * G * C) / V
I’ve provided an example value for all except G, which is anyone’s guess. I think 1 billion client GETs per day in a network of 1 million vaults is realistic, to the low side even. This results in a daily 60 GB up- and download burden for routing for every vault, which is about 0.7 MB/s.
We haven’t included other message types (PUT’s and such), nor churn, nor actual farming, only routing. All this considered, I doubt it is feasible to farm on smartphone connections or in areas where telecommunication infrastructure is poor. I’m even concerned about whether it’s possible to farm on home connections in countries with high quality infrastructure. Even if you don’t have a datacap, your ISP probably isn’t going to let you get away with a daily consumption of 60 GB upload bandwidth.
Please make my day by poking some big holes in my reasoning?