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Date: Mon, 30 Apr 2012 20:26:26 +0200
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From: Wladimir <laanwj@gmail.com>
To: "Rebroad (sourceforge)" <rebroad+sourceforge.net@gmail.com>
Content-Type: multipart/alternative; boundary=047d7b3395a5904b2504bee997fb
Cc: bitcoin-development@lists.sourceforge.net
Subject: Re: [Bitcoin-development] BIP to improve the availability of blocks
Precedence: list

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On Mon, Apr 30, 2012 at 6:40 PM, Rebroad (sourceforge) <
rebroad+sourceforge.net@gmail.com> wrote:

>
> My proposal is that in addition to the size (which is advertised in
> the header), the hash is also advertised in the header (of a block).
> This would help nodes to determine whether they wanted to reject the
> download. (e.g. if it already had a block matching that hash). This of
> course wouldn't prevent a rogue node from sending an incorrect hash,
> but this would aid in saving bandwidth amongst behaving nodes.
>

I suppose it would make sense for clients to be able to reject blocks that
they already have, if that's not currently possible.

The other part of the proposal is to allow nodes to request upload and
> download blocks that have already been partially downloaded.
>
> This could be done by modifying the existing methods of upload,
> download, or by adding a new method, perhaps even using HTTP/HTTPS or
> something similar. This would also help nodes to obtain the blockchain
> who have restrictive ISPs, especially if they are being served on port
> 80 or 443. This could perhaps also allow web caches to keep caches of
> the blockchain, thereby making it also more available also.
>

You don't need a BIP if you want to somehow fetch the (initial) block chain
outside the bitcoin protocol. You could download it from some http server
or even pass it along on an USB stick. Then with a simple client change you
can import it: https://github.com/bitcoin/bitcoin/pull/883 .

Currently, without this functionality, nodes with restrictive (or
> slow) internet have some options, such as going via a tor proxy, but
> due to the latency, the problem with multiple receptions of the same
> block still occur.
>

If you're behind such a slow internet connection, and concerned about every
bit of bandwidth, it is better to run a lightweight node. For example,
Electrum.

Even if you could reduce the wasted bandwidth a bit by puzzling around with
partial blocks, the download will still be substantial (and that's going to
get worse before it gets better).

Wladimir

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On Mon, Apr 30, 2012 at 6:40 PM, Rebroad (sourceforge) <span dir=3D"ltr">&l=
t;<a href=3D"mailto:rebroad+sourceforge.net@gmail.com" target=3D"_blank">re=
broad+sourceforge.net@gmail.com</a>&gt;</span> wrote: <br><div class=3D"gma=
il_quote">
<blockquote class=3D"gmail_quote" style=3D"margin:0pt 0pt 0pt 0.8ex;border-=
left:1px solid rgb(204,204,204);padding-left:1ex">
<br>
My proposal is that in addition to the size (which is advertised in<br>
the header), the hash is also advertised in the header (of a block).<br>
This would help nodes to determine whether they wanted to reject the<br>
download. (e.g. if it already had a block matching that hash). This of<br>
course wouldn&#39;t prevent a rogue node from sending an incorrect hash,<br=
>
but this would aid in saving bandwidth amongst behaving nodes.<br></blockqu=
ote><div><br>I suppose it would make sense for clients to be able to reject=
 blocks that they already have, if that&#39;s not currently possible.<br>
<br></div><blockquote class=3D"gmail_quote" style=3D"margin:0pt 0pt 0pt 0.8=
ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
The other part of the proposal is to allow nodes to request upload and<br>
download blocks that have already been partially downloaded.<br>
<br>
This could be done by modifying the existing methods of upload,<br>
download, or by adding a new method, perhaps even using HTTP/HTTPS or<br>
something similar. This would also help nodes to obtain the blockchain<br>
who have restrictive ISPs, especially if they are being served on port<br>
80 or 443. This could perhaps also allow web caches to keep caches of<br>
the blockchain, thereby making it also more available also.<br></blockquote=
><div><br>You don&#39;t need a BIP if you want to somehow fetch the (initia=
l) block chain=20
outside the bitcoin protocol. You could download it from some http=20
server or even pass it along on an USB stick. Then with a simple client cha=
nge you can import it: <a href=3D"https://github.com/bitcoin/bitcoin/pull/8=
83">https://github.com/bitcoin/bitcoin/pull/883</a> .<br><br></div><blockqu=
ote class=3D"gmail_quote" style=3D"margin:0pt 0pt 0pt 0.8ex;border-left:1px=
 solid rgb(204,204,204);padding-left:1ex">


Currently, without this=C2=A0functionality, nodes with restrictive (or<br>
slow) internet have some options, such as going via a tor proxy, but<br>
due to the latency, the problem with multiple receptions of the same<br>
block still occur.<br></blockquote><div><br>If you&#39;re behind such a slo=
w internet connection, and concerned about=20
every bit of bandwidth, it is better to run a lightweight node. For example=
, Electrum.<br>
<br>Even if you could reduce the wasted bandwidth a bit by puzzling=20
around with partial blocks, the download will still be substantial (and tha=
t&#39;s going to get worse before it gets better). <br><br>Wladimir<br><br>=
</div></div>

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