[bitcoin-dev] Hard fork proposal from last week's meeting

Johnson Lau jl2012 at xbt.hk
Wed Mar 29 15:34:41 UTC 2017


> On 29 Mar 2017, at 14:24, Emin Gün Sirer via bitcoin-dev <bitcoin-dev at lists.linuxfoundation.org> wrote:
> 
> >Even when several of the experts involved in the document you refer has my respect and admiration, I do not agree with some of their conclusions
> 
> I'm one of the co-authors of that study. I'd be the first to agree with your conclusion
> and argue that the 4MB size suggested in that paper should not be used without
> compensation for two important changes to the network.
> 
> Our recent measurements of the Bitcoin P2P network show that network speeds
> have improved tremendously. From February 2016 to February 2017, the average
> provisioned bandwidth of a reachable Bitcoin node went up by approximately 70%. 
> And that's just in the last year.

4 * 144 * 30 = 17.3GB per month, or 207GB per year. Full node initialisation will become prohibitive for most users until a shortcut is made (e.g. witness pruning and UTXO commitment but these are not trust-free)

> 
> Further, the emergence of high-speed block relay networks, like Falcon (http://www.falcon-net.org <http://www.falcon-net.org/>)
> and FIBRE, as well as block compression, e.g. BIP152 and xthin, change the picture dramatically. 

Also as the co-author of the selfish mining paper, you should know all these technology assume big miners being benevolent.

> 
> So, the 4MB limit mentioned in our paper should not be used as a protocol limit today. 
> 
> Best,
> - egs
> 
> 
> 
> On Tue, Mar 28, 2017 at 3:36 PM, Juan Garavaglia via bitcoin-dev <bitcoin-dev at lists.linuxfoundation.org <mailto:bitcoin-dev at lists.linuxfoundation.org>> wrote:
> Alphonse,
> 
>  
> 
> Even when several of the experts involved in the document you refer has my respect and admiration, I do not agree with some of their conclusions some of their estimations are not accurate other changed like Bootstrap Time, Cost per Confirmed Transaction they consider a network of 450,000,00 GH and today is 3.594.236.966 GH, the energy consumption per GH is old, the cost of electricity is wrong even when the document was made and is hard to find any parameter used that is valid for an analysis today.
> 
>  
> 
> Again with all respect to the experts involved in that analysis is not valid today.
> 
>  
> 
> I tend to believe more in Moore’s law, Butters' Law of Photonics and Kryder’s Law all has been verified for many years and support that 32 MB in 2020 are possible and equals or less than 1 MB in 2010.
> 
>  
> 
> Again may be is not possible Johnson Lau and LukeJr invested a significant amount of time investigating ways to do a safe HF, and may be not possible to do a safe HF today but from processing power, bandwidth and storage is totally valid and Wang Chung proposal has solid grounds.
> 
>  
> 
> Regards
> 
>  
> 
> Juan
> 
>  
> 
>  
> 
> From: Alphonse Pace [mailto:alp.bitcoin at gmail.com <mailto:alp.bitcoin at gmail.com>] 
> Sent: Tuesday, March 28, 2017 2:53 PM
> To: Juan Garavaglia <jg at 112bit.com <mailto:jg at 112bit.com>>; Wang Chun <1240902 at gmail.com <mailto:1240902 at gmail.com>>
> Cc: Bitcoin Protocol Discussion <bitcoin-dev at lists.linuxfoundation.org <mailto:bitcoin-dev at lists.linuxfoundation.org>>
> 
> 
> Subject: Re: [bitcoin-dev] Hard fork proposal from last week's meeting
> 
>  
> 
> Juan,
> 
>  
> 
> I suggest you take a look at this paper: http://fc16.ifca.ai/bitcoin/papers/CDE+16.pdf <http://fc16.ifca.ai/bitcoin/papers/CDE+16.pdf>  It may help you form opinions based in science rather than what appears to be nothing more than a hunch.  It shows that even 4MB is unsafe.  SegWit provides up to this limit.
> 
>  
> 
> 8MB is most definitely not safe today.
> 
>  
> 
> Whether it is unsafe or impossible is the topic, since Wang Chun proposed making the block size limit 32MiB.  
> 
>  
> 
>  
> 
> Wang Chun,
> 
> 
> Can you specify what meeting you are talking about?  You seem to have not replied on that point.  Who were the participants and what was the purpose of this meeting?
> 
>  
> 
> -Alphonse
> 
>  
> 
> On Tue, Mar 28, 2017 at 12:33 PM, Juan Garavaglia <jg at 112bit.com <mailto:jg at 112bit.com>> wrote:
> 
> Alphonse,
> 
>  
> 
> In my opinion if 1MB limit was ok in 2010, 8MB limit is ok on 2016 and 32MB limit valid in next halving, from network, storage and CPU perspective or 1MB was too high in 2010 what is possible or 1MB is to low today.
> 
>  
> 
> If is unsafe or impossible to raise the blocksize is a different topic. 
> 
>  
> 
> Regards
> 
>  
> 
> Juan
> 
>  
> 
>  
> 
> From: bitcoin-dev-bounces at lists.linuxfoundation.org <mailto:bitcoin-dev-bounces at lists.linuxfoundation.org> [mailto:bitcoin-dev-bounces at lists.linuxfoundation.org <mailto:bitcoin-dev-bounces at lists.linuxfoundation.org>] On Behalf Of Alphonse Pace via bitcoin-dev
> Sent: Tuesday, March 28, 2017 2:24 PM
> To: Wang Chun <1240902 at gmail.com <mailto:1240902 at gmail.com>>; Bitcoin Protocol Discussion <bitcoin-dev at lists.linuxfoundation.org <mailto:bitcoin-dev at lists.linuxfoundation.org>>
> Subject: Re: [bitcoin-dev] Hard fork proposal from last week's meeting
> 
>  
> 
> What meeting are you referring to?  Who were the participants?
> 
>  
> 
> Removing the limit but relying on the p2p protocol is not really a true 32MiB limit, but a limit of whatever transport methods provide.  This can lead to differing consensus if alternative layers for relaying are used.  What you seem to be asking for is an unbound block size (or at least determined by whatever miners produce).  This has the possibility (and even likelihood) of removing many participants from the network, including many small miners.  
> 
>  
> 
> 32MB in less than 3 years also appears to be far beyond limits of safety which are known to exist far sooner, and we cannot expect hardware and networking layers to improve by those amounts in that time.
> 
>  
> 
> It also seems like it would be much better to wait until SegWit activates in order to truly measure the effects on the network from this increased capacity before committing to any additional increases.
> 
>  
> 
> -Alphonse
> 
>  
> 
>  
> 
>  
> 
> On Tue, Mar 28, 2017 at 11:59 AM, Wang Chun via bitcoin-dev <bitcoin-dev at lists.linuxfoundation.org <mailto:bitcoin-dev at lists.linuxfoundation.org>> wrote:
> 
> I've proposed this hard fork approach last year in Hong Kong Consensus
> but immediately rejected by coredevs at that meeting, after more than
> one year it seems that lots of people haven't heard of it. So I would
> post this here again for comment.
> 
> The basic idea is, as many of us agree, hard fork is risky and should
> be well prepared. We need a long time to deploy it.
> 
> Despite spam tx on the network, the block capacity is approaching its
> limit, and we must think ahead. Shall we code a patch right now, to
> remove the block size limit of 1MB, but not activate it until far in
> the future. I would propose to remove the 1MB limit at the next block
> halving in spring 2020, only limit the block size to 32MiB which is
> the maximum size the current p2p protocol allows. This patch must be
> in the immediate next release of Bitcoin Core.
> 
> With this patch in core's next release, Bitcoin works just as before,
> no fork will ever occur, until spring 2020. But everyone knows there
> will be a fork scheduled. Third party services, libraries, wallets and
> exchanges will have enough time to prepare for it over the next three
> years.
> 
> We don't yet have an agreement on how to increase the block size
> limit. There have been many proposals over the past years, like
> BIP100, 101, 102, 103, 104, 105, 106, 107, 109, 148, 248, BU, and so
> on. These hard fork proposals, with this patch already in Core's
> release, they all become soft fork. We'll have enough time to discuss
> all these proposals and decide which one to go. Take an example, if we
> choose to fork to only 2MB, since 32MiB already scheduled, reduce it
> from 32MiB to 2MB will be a soft fork.
> 
> Anyway, we must code something right now, before it becomes too late.
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>  
> 
> 
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