Comparative Analysis of Lightning's Routing Clients

Lightning Network, the off-chain solution to Bitcoin, uses a combination of source routing, layered encryption and conditional commitments to perform anonymous and atomic multi-hop off-chain payments. The three predominant routing clients used in Lightning - LND, c- Lightning and Eclair - differ in their cost functions for adding channels to a payment path and hence result in differ paths. At the moment, there is no detailed study on how the different path selections affect the quality of the payment in terms of effectiveness and efficiency. Such an evaluation is needed to i) allow users to make informed choices of which client to use, and ii) enable developers of new routing algorithms to take lessons learned from the current designs into account. In this work, we analyze and compare the three predominant routing clients used by Lightning in terms of the path length, maximal delays a payment might experience, fee borne by the sender and success rate of multi-hop transactions. Based on our experiments and results, we recommend LND for users desiring payments with short paths and high success rates, c- Lightning for users desiring paths with low maximal latencies, and Eclair for those looking for cheap paths in terms of fees paid to the nodes that route payments as intermediaries. We further give guidelines for the design of future routing algorithms based on our insights gained from Lightning's current routing.