Let's say an attacker wants to use/exhaust the network's bandwidth, and
has the choice between renting resources from a commercial provider and
getting the network to "spam" itself it by sending unconfirmed
transactions. We'd like the latter to be more expensive than the former.
The bandwidth for relaying a transaction across the network is roughly
its serialized size (plus relay overhead) x number of nodes. A 1000vB
transaction is 1000-4000B serialized. With 100k nodes, that's 0.1-0.4GB
If the going rate for commercial services is 10c/GB, that's like 1-4c per kvB
of transaction data, so a 1000vB transaction should pay at least $0.04.
At a price of 120k USD/BTC, 100sat is about $0.12. This price allows us
to tolerate a large decrease in the conversion rate or increase in the
number of nodes.
Github-Pull: #33106
Rebased-From: 6da5de58cabc4133c379baa50845e30e5bc6b3e4
Recently added mempool_util implementation probably evolved in parallel with the package RBF one before being submitted as part of ephemeral dust in e2e30e89ba4b9bdbcabaf5b4346610922f0728bb.
