From denis.d.gorbachev at gmail.com  Wed Dec 16 05:01:37 2015
From: denis.d.gorbachev at gmail.com (Denis Gorbachev)
Date: Wed, 16 Dec 2015 05:01:37 +0000
Subject: [Lightning-dev] Transaction time
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	<87a8pbxnrj.fsf@rustcorp.com.au>
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Rusty, Mark - thanks for the explanations!

On Wed, Dec 16, 2015 at 10:49 AM Mark Friedenbach <mark at friedenbach.org>
wrote:

> It should be noted that this estimation is biasing towards
> worst-case-latency/best-case-decentralization. Even though we will make
> conscious efforts to keep lightning networks as decentralized as possible,
> it is still the case that we will see some centralization pressure due to
> the desire for low latency transactions. I expect that the average user's
> experience of a 10-hop payment would be on the order of 1-2 seconds, with
> the inner-hops being between Tier-1 datacenter nodes primarily with payment
> channels chosen based on network proximity. A 'near' payment to someone
> closer to them would be under a second. But it is very good to know that a
> network consisting entirely of last-mile endpoints geographically
> distributed around the world would only have a worst-case transaction time
> of only about 10s or so. Even that is doable for PoS.
>
> On Wed, Dec 16, 2015 at 8:04 AM, Rusty Russell <rusty at rustcorp.com.au>
> wrote:
>
>> Denis Gorbachev <denis.d.gorbachev at gmail.com> writes:
>> > Assuming a simple case of "Consumer - Relay - Provider" (2 hops), how
>> long
>> > should it take for provider to receive the payment?
>>
>> Assuming established channels already (assuming CPU is instant, so we're
>> just paying for network latency):
>>
>> Consumer offers Relay a contract:
>>         C -> R: update_add_htlc
>>         R -> C: update_accept
>>         C -> R: update_signature
>>         R -> C: update_complete*
>>
>> Relay offers Provider a contract:
>>         R -> P: update_add_htlc
>>         P -> R: update_accept
>>         R -> P: update_signature
>>         P -> R: update_complete*
>>
>> Provider closes contract with relay:
>>         P -> R: update_fulfill_htlc
>>         R -> P: update_accept
>>         P -> R: update_signature
>>         R -> P: update_complete*
>>
>> Relay closes contract with Client:
>>         R -> C: update_fulfill_htlc
>>         C -> R: update_accept
>>         R -> C: update_signature
>>         C -> R: update_complete*
>>
>> You don't need to wait for the update_complete packets to arrive, so
>> that works out to 3 RTTs per hop.  You might expect up to 10 hops in a
>> large lightning network, so 30 RTTs.
>>
>> I'm in Australia, and my bitcoin node latency averages 330ms (ouch!).
>> So that would be 10 seconds.
>>
>> Hope that helps!
>> Rusty.
>>
> _______________________________________________
>> Lightning-dev mailing list
>> Lightning-dev at lists.linuxfoundation.org
>> https://lists.linuxfoundation.org/mailman/listinfo/lightning-dev
>>
> --
@DenGorbachev <https://twitter.com/DenGorbachev>
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