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Date: Sun, 31 May 2015 15:49:05 -0400
Message-ID: <CABsx9T3UXCeh_-5bpKiF53+9LrufN596LnFyRq4fqN7PcVq7jg@mail.gmail.com>
From: Gavin Andresen <gavinandresen@gmail.com>
To: gb <kiwigb@yahoo.com>
Content-Type: multipart/alternative; boundary=001a11c382d07feeb00517660045
Cc: Bitcoin Dev <bitcoin-development@lists.sourceforge.net>
Subject: Re: [Bitcoin-development] [Bulk] Re: Fwd: Block Size Increase
	Requirements
Precedence: list

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On Sun, May 31, 2015 at 9:31 AM, gb <kiwigb@yahoo.com> wrote:

> Aren't you calculating bandwidth for a singly-connected node? A "highly
> connected" miner could have 30-100 node connections so you probably need
> to increase your traffic estimates by that factor.
>
> I.e. For 100MB blocks, 30-100 Mbps and $60-$100 per day data costs.
>

No, randomly connected gossip networks (which is what the Bitcoin p2p
network is) don't work that way, bandwidth is (roughly) O(N) where N is the
number of bytes relayed to everybody.

(it is actually a small multiple of N, because of the overhead of 'inv'
messages, and if we ever get really serious about scaling up we'll need to
fix the protocol to reduce that overhead, but that won't be a problem for
years).


-- 
--
Gavin Andresen

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<div dir=3D"ltr"><div class=3D"gmail_extra"><div class=3D"gmail_quote">On S=
un, May 31, 2015 at 9:31 AM, gb <span dir=3D"ltr">&lt;<a href=3D"mailto:kiw=
igb@yahoo.com" target=3D"_blank">kiwigb@yahoo.com</a>&gt;</span> wrote:<br>=
<blockquote class=3D"gmail_quote" style=3D"margin:0 0 0 .8ex;border-left:1p=
x #ccc solid;padding-left:1ex"><div id=3D":1rq" class=3D"a3s" style=3D"over=
flow:hidden">Aren&#39;t you calculating bandwidth for a singly-connected no=
de? A &quot;highly<br>
connected&quot; miner could have 30-100 node connections so you probably ne=
ed<br>
to increase your traffic estimates by that factor.<br>
<br>
I.e. For 100MB blocks, 30-100 Mbps and $60-$100 per day data costs.<br></di=
v></blockquote></div><br>No, randomly connected gossip networks (which is w=
hat the Bitcoin p2p network is) don&#39;t work that way, bandwidth is (roug=
hly) O(N) where N is the number of bytes relayed to everybody.</div><div cl=
ass=3D"gmail_extra"><br></div><div class=3D"gmail_extra">(it is actually a =
small multiple of N, because of the overhead of &#39;inv&#39; messages, and=
 if we ever get really serious about scaling up we&#39;ll need to fix the p=
rotocol to reduce that overhead, but that won&#39;t be a problem for years)=
.<br><br clear=3D"all"><div><br></div>-- <br><div class=3D"gmail_signature"=
>--<br>Gavin Andresen<br></div>
</div></div>

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