To: Pieter Wuille <pieter.wuille@gmail.com>,
	Bitcoin Protocol Discussion <bitcoin-dev@lists.linuxfoundation.org>,
	Juan Garavaglia <jg@112bit.com>
References: <SC1P152MB1648D0F9DF4279C49D755233F53F0@SC1P152MB1648.LAMP152.PROD.OUTLOOK.COM>
	<CAPg+sBjrjUFJZnCtmcvZYs_pc4T3YzU_jtK+eZANyGKSLavrXg@mail.gmail.com>
From: Eric Voskuil <eric@voskuil.org>
Message-ID: <cfdd397d-afac-e0c3-b347-558152d7a81b@voskuil.org>
Date: Thu, 23 Mar 2017 18:58:37 -0700
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Subject: Re: [bitcoin-dev] Issolated Bitcoin Nodes
Precedence: list

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On 03/23/2017 05:20 PM, Pieter Wuille via bitcoin-dev wrote:
> On Thu, Mar 23, 2017 at 3:37 PM, Juan Garavaglia via bitcoin-dev 
> <bitcoin-dev@lists.linuxfoundation.org> wrote:
>> Long story short, when nodes 0.13+ receive blocks from 0.13+
>> nodes all is ok, and those blocks propagate to older nodes with
>> no issues. But when a block tries to be propagated from bitcoind
>> 0.12.+ to newer ones those blocks are NOT being propagated to the
>> peers with newer versions while these newer blocks are being
>> propagated to peers with older versions with no issues.
>> 
>> My conclusion is that we have a backward compatibility issue
>> between 0.13.X+ and older versions.
> 
> Hello Juan,
> 
> this is expected behaviour. Nodes with segwit active only download 
> blocks from other segwit peers, as old peers cannot provide the 
> witness data they need to verify the blocks.

Juan's statement pertains to incompatibility, not mysterious causation.

Clearly it's a material consideration. Is it an oversight that this is
not documented as an incompatibility in any of the segwit BIPs?

I don't recall any discussion on the importance of segwit bridge
nodes. Is there a plan for bridging mainnet?

e
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