Received: from sog-mx-3.v43.ch3.sourceforge.com ([172.29.43.193] helo=mx.sourceforge.net) by sfs-ml-4.v29.ch3.sourceforge.com with esmtp (Exim 4.76) (envelope-from ) id 1Z374D-0001Ol-Vu for bitcoin-development@lists.sourceforge.net; Thu, 11 Jun 2015 18:19:05 +0000 X-ACL-Warn: Received: from mail-oi0-f49.google.com ([209.85.218.49]) by sog-mx-3.v43.ch3.sourceforge.com with esmtps (TLSv1:RC4-SHA:128) (Exim 4.76) id 1Z3743-000429-KK for bitcoin-development@lists.sourceforge.net; Thu, 11 Jun 2015 18:19:05 +0000 Received: by oiha141 with SMTP id a141so8339155oih.0 for ; Thu, 11 Jun 2015 11:18:50 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:in-reply-to:references:date :message-id:subject:from:to:cc:content-type; bh=ZcSyQ2vpCLR6hDI6m1xy+PwwKMJvUV0vxMXOr99tI6E=; b=iCArYDefwGCehbDJJaY23GHJR9ScfI74cn1pqwMKfvT9IMrIhhl2KHpRvxK4Jt4f0V sK9aLINypKpcQ1JmDGFtzidV0jUGwVhnVR3BgQgdrcS7YFED5mT5otlKmqftT6LxyiXU /7TvTtFVIsF2VgQ4ywcA1lJoo1gUcKMOjUZuQTHV8jMTsTnWwDgsKFheGdVwPZHfOT2C PXjuYigLv8ILO45nwe3W2JkjFfahHN6rr8kl4gb+eQi3iRRRtjlSpJy6uUUmXhRgyDeg EMtChzPMparyOJi1m3eKx0yQHNlY7g+TgbGcglVg4w/hjAMA0CiU+Y04PcjcMImvhjtO 5hrA== X-Gm-Message-State: ALoCoQmrYppsHuvrsj3czW/wp6U8h5UhrUp6fqrGxixxlthuBpNZPQ7IExeAL8i4FLMx0dzXOzVd MIME-Version: 1.0 X-Received: by 10.202.170.82 with SMTP id t79mr8578263oie.40.1434046730152; Thu, 11 Jun 2015 11:18:50 -0700 (PDT) Received: by 10.182.47.229 with HTTP; Thu, 11 Jun 2015 11:18:50 -0700 (PDT) In-Reply-To: <20150611131048.GA24053@savin.petertodd.org> References: <20150611131048.GA24053@savin.petertodd.org> Date: Thu, 11 Jun 2015 12:18:50 -0600 Message-ID: From: Nathan Wilcox To: Peter Todd Content-Type: multipart/alternative; boundary=001a113c32ecf146e605184205af X-Spam-Score: 1.0 (+) X-Spam-Report: Spam Filtering performed by mx.sourceforge.net. See http://spamassassin.org/tag/ for more details. 1.0 HTML_MESSAGE BODY: HTML included in message X-Headers-End: 1Z3743-000429-KK Cc: Bitcoin Dev Subject: Re: [Bitcoin-development] Proposal: SPV Fee Discovery mechanism X-BeenThere: bitcoin-development@lists.sourceforge.net X-Mailman-Version: 2.1.9 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 11 Jun 2015 18:19:06 -0000 --001a113c32ecf146e605184205af Content-Type: text/plain; charset=UTF-8 On Thu, Jun 11, 2015 at 7:10 AM, Peter Todd wrote: > On Wed, Jun 10, 2015 at 02:18:30PM -0700, Aaron Voisine wrote: > > The other complication is that this will tend to be a lagging indicator > > based on network congestion from the last time you connected. If we > assume > > that transactions are being dropped in an unpredictable way when blocks > are > > full, knowing the network congestion *right now* is critical, and even > then > > you just have to hope that someone who wants that space more than you do > > doesn't show up after you disconnect. > > Hence the need for ways to increase fees on transactions after initial > broadcast like replace-by-fee and child-pays-for-parent. > > I haven't looked closely at replace-by-fee yet, but I assume this is a non-consensus change to mempool mechanics. To me, this seems like the "actuator" side of fee mechanics: it provides a transaction sender a way to influence the system. By contrast, learning about fees is the "sensor" side of fee mechanics. Consider how a replace-by-fee wallet makes fee decisions. When does it replace by fee? It needs feedback in one of two forms: a. Direct feedback from a trnasaction relay service, or: b. Information in the blockchain, which is verified by all verifying nodes and refined by all miners. The first kind of information is quite acceptable and practical for many use cases, but leave the wallet vulnerable to fabrications by that service. This vulnerability is precisely what SPV security intends to mitigate, right? With only information type a, a (non-SPV) wallet can "shop around" to find competing services, and this should work pretty well, provided the wallet can discover those competing services. If, OTOH, the wallet has access to information type b, it now has "perfect competition" across all such services, even when it can't discover the low-priced services directly. This actual-fees-in-the-actual-block-chain information of type b seem like a powerful source of pricing information, and if SPV security is already valuable for other reasons, then it seems natural to leverage that value. Re: "dropped in an unpredictable way" - transactions would be dropped > lowest fee/KB first, a completely predictable way. > > -- > 'peter'[:-1]@petertodd.org > 0000000000000000124bae79afdcee9267b4e6f8137758b8b4135455cd8e3bfd > > > ------------------------------------------------------------------------------ > > _______________________________________________ > Bitcoin-development mailing list > Bitcoin-development@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/bitcoin-development > > -- Nathan Wilcox Least Authoritarian email: nathan@leastauthority.com twitter: @least_nathan PGP: 11169993 / AAAC 5675 E3F7 514C 67ED E9C9 3BFE 5263 1116 9993 --001a113c32ecf146e605184205af Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
On Thu, Jun 11, 2015 at 7:10 AM, Peter Todd <pete@petert= odd.org> wrote:
On Wed, Jun 10,= 2015 at 02:18:30PM -0700, Aaron Voisine wrote:
> The other complication is that this will tend to be a lagging indicato= r
> based on network congestion from the last time you connected. If we as= sume
> that transactions are being dropped in an unpredictable way when block= s are
> full, knowing the network congestion *right now* is critical, and even= then
> you just have to hope that someone who wants that space more than you = do
> doesn't show up after you disconnect.

Hence the need for ways to increase fees on transactions after initi= al
broadcast like replace-by-fee and child-pays-for-parent.


I haven't looked closely at replac= e-by-fee yet, but I assume this is a non-consensus change to mempool mechan= ics. To me, this seems like the "actuator" side of fee mechanics:= it provides a transaction sender a way to influence the system.=C2=A0 By c= ontrast, learning about fees is the "sensor" side of fee mechanic= s.

Consider how a replace-by-fee wallet makes fee decisio= ns. When does it replace by fee?=C2=A0 It needs feedback in one of two form= s:

a. Direct feedback from a trnasaction relay service, o= r:

b. Information in the blockchain, which is verified by= all verifying nodes and refined by all miners.

The first= kind of information is quite acceptable and practical for many use cases, = but leave the wallet vulnerable to fabrications by that service. This vulne= rability is precisely what SPV security intends to mitigate, right?

With only information type a, a (non-SPV) wallet can &quo= t;shop around" to find competing services, and this should work pretty= well, provided the wallet can discover those competing services. If, OTOH,= the wallet has access to information type b, it now has "perfect comp= etition" across all such services, even when it can't discover the= low-priced services directly.

This actual-fees-in-the-ac= tual-block-chain information of type b seem like a powerful source of prici= ng information, and if SPV security is already valuable for other reasons, = then it seems natural to leverage that value.


<= blockquote class=3D"gmail_quote" style=3D"margin:0 0 0 .8ex;border-left:1px= #ccc solid;padding-left:1ex"> Re: "dropped in an unpredictable way" - transactions would be dro= pped
lowest fee/KB first, a completely predictable way.

--
'peter'[:-1]@pet= ertodd.org
0000000000000000124bae79afdcee9267b4e6f8137758b8b4135455cd8e3bfd

---------------------------------------------------------= ---------------------

_______________________________________________
Bitcoin-development mailing list
Bitcoin-develo= pment@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/bitcoin-de= velopment




--
Nathan Wilcox
Least Authoritarian

email: nathan@leastauthority.co= m
twitter: @least_nathan
PGP: 11169993 / AAAC 5675 E3F7 514C 67ED= =C2=A0E9C9 3BFE 5263 1116 9993
--001a113c32ecf146e605184205af--