Published on: 2020-01-07T14:57:41+00:00
In an email, a proposed algorithm for conducting payments that optimally reduces the imbalance of nodes during (multipath) payments was shared. The algorithm calculates the new node balance coefficient ν′u after a payment has been made, taking into account the total funds of the node and the sum of the capacities of its payment channels. The algorithm also computes values ζ(u,v1),…,ζ(u,vd) for all online channel partners, assuming channels are ordered in decreasing imbalance and omitting channels with an imbalance less than the new node balance coefficient.The suggestion was made that this algorithm could be useful for guiding the splitting of payments in multipath transactions. For example, if a payer named Alice has channels to Bob and Charlie, and Alice-Bob has an imbalance of 0.5, while Alice-Charlie has an imbalance of 0.5, then if Alice needs to make a payment of 0.1, it is recommended to split the payment into two parts: 0.05 via Alice-Bob and 0.05 via Alice-Charlie. It was asked whether this calculation could be derived from the published rule, where if one of the payer channels is imbalanced in favor of the payer, the payment should not be split, but if the payment would result in an imbalance against the payer, some amount should be split to another channel.A research paper titled "Imbalance measure and proactive channel rebalancing algorithm for the Lightning Network" by Rene Pickhardt and Mariusz Nowostawski was published on arxiv.org. The paper describes a protocol that significantly improves the success rate of single-unit payments in a balanced network. The success rate increases from 11.2% to 98.3%, and the median possible payment size across all pairs of participants increases from 0 to 0.5 mBTC for initial routing attempts on the cheapest path. Pickhardt suggests that this, combined with multi-part/path payments, could be the future of the lightning network.Pickhardt also proposes extending BOLTs (Basis of Lightning Technology) with two new gossip queries/replies, "query_want_rebalance_channel_ids" and "reply_want_rebalance_channel_ids," which would allow nodes to initiate fee-free rebalancing operations. However, he acknowledges the need for protection against probing attacks to safeguard node privacy. He also addresses the potential abuse of circular fee-free payments and suggests that open and transparent rebalancing cycles could be blocked if nodes feel they are being abused.Pickhardt welcomes feedback and discussion on his proposals for BOLT extensions, particularly BOLT 14, recognizing that it may be a controversial topic.
Updated on: 2023-07-31T22:29:51.989213+00:00