Revisiting pathfinding

The gossip protocol ensures widespread dissemination of messages by flooding the network, a method that becomes less reliable as the network expands. This unreliability can lead participants to depend on larger nodes, which might be custodial, for their node operations due to these nodes' higher liquidity and ability to more effectively probe the network.

A proposed solution to this pathfinding issue involves nodes requesting path information from their channel peers rather than relying solely on their own network maps or gossip data. This method, already implemented outside of the lightning protocol by the Phoenix wallet using the Acinq node, suggests that a node could ask a connected peer for a path to the desired destination. This peer-to-peer request chain continues until a viable path is established without needing to broadcast channel balances. This approach not only enhances payment reliability and custody control but also introduces the potential for nodes to adjust routing fees with greater precision.

However, this solution raises privacy concerns because it requires disclosing the transaction's destination to at least one channel peer. Despite these concerns, the shifting landscape towards "Lightning-as-a-Service" models indicates a growing preference for reliability over privacy among network participants. For those prioritizing privacy, reliance on gossip data remains an option. Additionally, the development of trampoline and blinded paths offers mechanisms to obscure destinations, suggesting a layered approach where the network’s core focus on reliability is complemented by optional privacy features. This strategy mirrors other networks where a reliable foundation supports added layers of privacy according to user preference.