1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
|
Return-Path: <decker.christian@gmail.com>
Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org
[172.17.192.35])
by mail.linuxfoundation.org (Postfix) with ESMTPS id 3B5EF957
for <bitcoin-dev@lists.linuxfoundation.org>;
Fri, 27 Jan 2017 21:28:15 +0000 (UTC)
X-Greylist: whitelisted by SQLgrey-1.7.6
Received: from mail-wm0-f46.google.com (mail-wm0-f46.google.com [74.125.82.46])
by smtp1.linuxfoundation.org (Postfix) with ESMTPS id 9799AE0
for <bitcoin-dev@lists.linuxfoundation.org>;
Fri, 27 Jan 2017 21:28:14 +0000 (UTC)
Received: by mail-wm0-f46.google.com with SMTP id c206so159487110wme.0
for <bitcoin-dev@lists.linuxfoundation.org>;
Fri, 27 Jan 2017 13:28:14 -0800 (PST)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025;
h=date:from:to:subject:message-id:mail-followup-to:references
:mime-version:content-disposition:in-reply-to:user-agent;
bh=PJPEOOvFMTfUWQPI920CIlhjn//5rJzHrUTcqKXaKUI=;
b=oNIZbouT9Jen/BHXfqqKVwuo7V1NkmdRRHCGLeZV/O8NeD3CUANfZIjW+NhdF+lGG9
e8I+e1WrSY2zbK+G60MI46qN5A+qmZxzngplo3c7cYxJS6v7TH50TRDyqTiUMI7v5jp+
huOoX+OhTZerMorXwyfYql95jClmbAXMxMMfRFuVqLHphCx7M2jRnqnte7DbCn2bBbDo
N1ZR5/68sRFC3SHRuPNqcHLqNtgO4wl77d65sUxiz7+5K6Ag15vHpGG9ZCYZyP1ce531
BnwVPFRUfSfq2Lcu4d3VLbb5QGccZIrW0FvwlGs49z0T4TJwwgwyEmq3m6bdO6hgrxp6
N2Bg==
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;
d=1e100.net; s=20161025;
h=x-gm-message-state:date:from:to:subject:message-id:mail-followup-to
:references:mime-version:content-disposition:in-reply-to:user-agent;
bh=PJPEOOvFMTfUWQPI920CIlhjn//5rJzHrUTcqKXaKUI=;
b=JUCRbvY5x0hwFIPpGNZSPb7UX81N4fhTohn/sCEu39580E4jd0WqUdx8z6YIR6sJAq
v2jhn/k2A+M7U0R7vG7Xz0gR7rrN3ijKlaHcPOZVNMG/97TJZN22x3B11K/zjl1U/45Y
Ks4aJsqxYuYg4NtE2qBm9MShOvph69ySnY1whmoCc91iNYrAheVInwO24bN9dPxa8LQ7
BdoKUQeeqGXSuh5oSiAIOdn22h4IAwOvDpbRk8n5AkoHNoNai5K1NeYO0ifnUpgq8zei
ZW7ElKQgtglDTt/E7AzcW7J92qhk5bA6xm9/7BIYlo3piJ4LsJATINArXLKCmwp/Rh8E
821g==
X-Gm-Message-State: AIkVDXL1k2hKKiW3wpjYPuRj31Z+kgLHXIBp+U2qOyLGOH7R24h1gY+y18Pd89zS8nLawQ==
X-Received: by 10.223.175.49 with SMTP id z46mr10993020wrc.84.1485552492883;
Fri, 27 Jan 2017 13:28:12 -0800 (PST)
Received: from nex ([2a02:aa16:1105:4a80:6410:eecc:2c5:aa08])
by smtp.gmail.com with ESMTPSA id b8sm9746264wrb.17.2017.01.27.13.28.11
for <bitcoin-dev@lists.linuxfoundation.org>
(version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128);
Fri, 27 Jan 2017 13:28:11 -0800 (PST)
Date: Fri, 27 Jan 2017 22:28:10 +0100
From: Christian Decker <decker.christian@gmail.com>
To: bitcoin-dev@lists.linuxfoundation.org
Message-ID: <20170127212810.GA5856@nex>
Mail-Followup-To: Christian Decker <decker.christian@gmail.com>,
bitcoin-dev@lists.linuxfoundation.org
References: <201701270107.01092.luke@dashjr.org>
<CAAy62_+1OjF3V5g4wpOyW0KtNGodddJu_cxOfG-f+8LB7D=rPA@mail.gmail.com>
<CAAy62_JuWMQ=HMmcw8GsQSDM8S+4LJeG1GHw1OdT+mQC3H-DOA@mail.gmail.com>
<201701270414.18553.luke@dashjr.org>
<CAAy62_LHtrx7k73kznMpPvheA--0T9YiHkjHArf2KK0Qt+ViUg@mail.gmail.com>
<CAAy62_LeNi1djDmArX0RWW=rD0GJU9eSqCy0o4G9eg3Y7O+0Wg@mail.gmail.com>
<CAMZUoKnxqxvPQehdWo1ZaHB-1-od4cHvJRDTmF5x7ty1CdLbUQ@mail.gmail.com>
<CAMZUoK=eb3jgA7Rwt38tvZt0tYk7gRVPc_2=HUWg1L_vaD93uw@mail.gmail.com>
<CAMZUoKmUH7ah7pnUgLHFtwYacw2=v3rJ0-csJ8thRy=REM92iw@mail.gmail.com>
<CAB3F3DviHkQo9ndYphOgUvgSum9TTzX=AA_Acdf-9sZJ7TuHuQ@mail.gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <CAB3F3DviHkQo9ndYphOgUvgSum9TTzX=AA_Acdf-9sZJ7TuHuQ@mail.gmail.com>
User-Agent: Mutt/1.5.23.1 (2014-03-12)
X-Spam-Status: No, score=-1.5 required=5.0 tests=BAYES_00,DKIM_SIGNED,
DKIM_VALID, DKIM_VALID_AU, FREEMAIL_FROM, RCVD_IN_DNSWL_NONE,
RCVD_IN_SORBS_SPAM autolearn=no version=3.3.1
X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on
smtp1.linux-foundation.org
Subject: Re: [bitcoin-dev] Three hardfork-related BIPs
X-BeenThere: bitcoin-dev@lists.linuxfoundation.org
X-Mailman-Version: 2.1.12
Precedence: list
List-Id: Bitcoin Protocol Discussion <bitcoin-dev.lists.linuxfoundation.org>
List-Unsubscribe: <https://lists.linuxfoundation.org/mailman/options/bitcoin-dev>,
<mailto:bitcoin-dev-request@lists.linuxfoundation.org?subject=unsubscribe>
List-Archive: <http://lists.linuxfoundation.org/pipermail/bitcoin-dev/>
List-Post: <mailto:bitcoin-dev@lists.linuxfoundation.org>
List-Help: <mailto:bitcoin-dev-request@lists.linuxfoundation.org?subject=help>
List-Subscribe: <https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev>,
<mailto:bitcoin-dev-request@lists.linuxfoundation.org?subject=subscribe>
X-List-Received-Date: Fri, 27 Jan 2017 21:28:15 -0000
On Fri, Jan 27, 2017 at 03:47:20PM -0500, Greg Sanders via bitcoin-dev wrote:
> Note that the 4MB number comes from a single network metric.
>
> Quotes directly from the paper in question:
> http://fc16.ifca.ai/bitcoin/papers/CDE+16.pdf
>
> >Our results hinge on the key metric of effective throughput in the overlay
> network, which we define here as which blocks propagate within an average
> block interval period the percentage of nodes to.
> ...
> >Note that as we consider only a subset of possible metrics (due to
> difficulty in accurately measuring others), our results on
> reparametrization may be viewed as upper bounds: additional metrics could
> reveal even stricter limits.
>
> It says nothing about any mining centralization pressure, DoS attacks, etc.
> A single metric among many we have to contend with.
>
As one of the authors of that paper and the source of the measurement
data I'd also like to point out that the 4MB number is indeed intended
as an optimistic upper bound on todays network capacity.
More importantly it's not a black and white situation, where there is
a magic number beyond which Bad Things (TM) happen, it's a spectrum on
which we can see a few threshold beyond which we _know_ Bad Things
definitely happen. Miner centralization pressure is felt earlier.
|
