From niftynei at gmail.com  Thu Jun 30 03:06:50 2022
From: niftynei at gmail.com (lisa neigut)
Date: Wed, 29 Jun 2022 22:06:50 -0500
Subject: [Lightning-dev] Achieving Zero Downtime Splicing in Practice
 via Chain Signals
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Had another thought: if you've seen a chain close but also have a gossip
message that
indicates this is a splice, you SHOULD propagate that gossip more
urgently/widely than
any other gossip you've got. Adding an urgency metric to gossip is fuzzy to
enforce... *handwaves*.

You *do* get the onchain signal, we just change the behavior of the
secondary information system
instead of embedding the info into the chain..

"Spamming" gossip with splices expensive -- there's a real-world cost
(onchain fees) to
closing a channel (the signal to promote/prioritize a gossip msg) which
cuts down on the ability to send out these 'urgent' messages with any
frequency.

~nifty

On Wed, Jun 29, 2022 at 7:43 PM lisa neigut <niftynei at gmail.com> wrote:

> Adding a noticeable on-chain signal runs counter to the goal of the move
> to taproot / gossip v2, which is to make lightning's onchain footprint
> indistinguishable from
> any other onchain usage.
>
> I'm admittedly a bit confused as to why onchain signals are even being
> seriously
>  proposed. Aside from "infallibility", is there another reason for
> suggesting
> we add an onchain detectable signal for this? Seems heavy handed imo,
> given
> that the severity of a comms failure is pretty minimal (*potential* for
> lost routing fees).
>
> > So it appears you don't agree that the "wait N blocks before you close
> your
> channels" isn't a fool proof solution? Why 12 blocks, why not 15? Or 144?
>
> fwiw I seem to remember seeing that it takes  ~an hour for gossip to
> propagate
> (no link sorry). Given that, 2x an hour or 12 blocks is a reasonable first
> estimate.
> I trust we'll have time to tune this after we've had some real-world
> experience with them.
>
> Further, we can always add more robust signaling later, if lost routing
> fees turns
> out to be a huge issue.
>
> Finally, worth noting that Alex Myer's minisketch project may well
> help/improve gossip
> reconciliation efficiency to the point where gossip reliability is less
> of an issue.
>
> ~nifty
>
>
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