Spec Meeting - 17.Jan.2022

There were two pull requests merged: Informing peers about an IP address change and facilitating peer communications before unilateral closes. The IRC meeting was cut a bit shorter than usual due to the US Holiday.

Merged Pull Requests

• #917 - BOLT 1: adds remote address to optional init_tlvs (IP discovery)
  • This notifies a peer when its IP has changed so that it can inform its other peers of the change as well.
• #942 - Removed requirement to broadcast an outdated commitment transaction
  • Instead of immediately unilaterally closing a channel upon discovering that a peer is unable to provide the most up to date channel balance state, this allows the peer other options to recover the state or wait for the peer to send an error before unilaterally closing.

Open Pull Requests

• #910 - Explicitly allow funding_locked early, and support alias scids
  • No second implementation yet. This would allow channel peers to acknowledge payments using an alias until a short channel id is confirmed onchain at a “funding depth of zero”. This is an intended UX improvement for rapid onboarding of new users. They can receive payments on Lightning instantly without needing to wait for multiple blocks onchain to set up a lightning channel. It is a nuanced topic with many risk tolerances and UX tradeoffs which we will explore in a future deep dive.
• #911 - BOLT 7: add gossip address descriptor type DNS hostname
  • This allows node operators to announce a symbolic name such as a domain name to remain reachable despite an IP change.
• #919 - Add a max_dust_htlc_exposure_msat
  • No second implementation yet, just needs cross implementation check. This limits the amount a miner would earn in the event of a unilateral close to a max dust amount plus transaction fees. It caps the amount that is not explicitly associated with one of the channel peers or an HTLC that would be used as fees.
• #941 - Clarification how messages are referred to
  • A clarification to BOLT 1 messages.