The dynamics of the Bitcoin relay network can be complex, especially when nodes on the network are running different relay policies. These policies determine which transactions are propagated across the network and which ones are filtered out. In a homogenous network where all nodes have the same relay policy, transactions should propagate seamlessly. However, when nodes have heterogenous policies, the network’s efficiency can be compromised.
The Bitcoin relay network operates on a flood-fill architecture, where transactions are forwarded to every connected node except the one it originated from. This architecture ensures that transactions eventually reach miners for confirmation. Introducing filters in relay policies can impede transaction propagation and reduce the network’s reliability.
In a scenario where some nodes filter out certain transactions while others propagate them, a minority of nodes can ensure the transactions still reach miners. This tolerant minority creates a sub-network within the larger network to guarantee transaction propagation. Even if the majority filters out transactions, a small group can maintain connectivity to miners.
If there is no tolerant minority, miners may set up alternative ways for users to submit filtered transactions for confirmation. Miners are profit-driven entities and will accommodate transactions that users are willing to pay for. Relay policies cannot censor transactions that are consensus valid and financially viable for miners.
Ultimately, relay policy is not a substitute for consensus rules. Undesirable transactions can only be prevented from confirmation through a consensus change. If transactions could be easily censored through relay policies, Bitcoin’s censorship resistance would be compromised. The network’s resilience lies in its ability to maintain consensus rules despite varying relay policies among nodes.