delvingbitcoin

0conf LN channels and v3 anchors

0conf LN channels and v3 anchors

Original Postby t-bast

Posted on: January 30, 2024 10:24 UTC

In the ongoing development and refinement of version 3 (v3), there is an intricate issue that revolves around the transaction topology, particularly concerning the funding transaction's interaction with unconfirmed inputs.

A potential solution under consideration involves limiting the funding transaction to exclude any unconfirmed inputs, creating a more straightforward A → B → {C, D, CPFP bump} structure. This approach aims to mitigate complexities; however, it raises concerns because it may inhibit the common practice of chaining unconfirmed splices, an essential feature for some users.

Moreover, while the system can function adequately if the funding transaction confirms independently or through the Child Pays For Parent (CPFP) method—assuming B has a change output—the necessity of a change output is not ideal. The current workaround involves incorporating a change output in the funding or splice transaction on B's side to enable the application of CPFP as a defensive measure against transaction pinning. Although not optimal, this method is a continuation of existing strategies and does not present new challenges specifically introduced by v3. This strategy suggests that while v3 brings certain improvements, it also retains some of the limitations of previous iterations that require workarounds like the use of CPFP for transaction confirmation.