Received: from sog-mx-1.v43.ch3.sourceforge.com ([172.29.43.191] helo=mx.sourceforge.net) by sfs-ml-2.v29.ch3.sourceforge.com with esmtp (Exim 4.76) (envelope-from ) id 1YzPYs-0006xk-GB for bitcoin-development@lists.sourceforge.net; Mon, 01 Jun 2015 13:15:26 +0000 Received-SPF: pass (sog-mx-1.v43.ch3.sourceforge.com: domain of gmail.com designates 209.85.217.174 as permitted sender) client-ip=209.85.217.174; envelope-from=gavinandresen@gmail.com; helo=mail-lb0-f174.google.com; Received: from mail-lb0-f174.google.com ([209.85.217.174]) by sog-mx-1.v43.ch3.sourceforge.com with esmtps (TLSv1:RC4-SHA:128) (Exim 4.76) id 1YzPYq-0002eC-PU for bitcoin-development@lists.sourceforge.net; Mon, 01 Jun 2015 13:15:26 +0000 Received: by lbcmx3 with SMTP id mx3so84084076lbc.1 for ; Mon, 01 Jun 2015 06:15:18 -0700 (PDT) MIME-Version: 1.0 X-Received: by 10.152.5.134 with SMTP id s6mr20112038las.99.1433164518382; Mon, 01 Jun 2015 06:15:18 -0700 (PDT) Received: by 10.25.90.75 with HTTP; Mon, 1 Jun 2015 06:15:18 -0700 (PDT) In-Reply-To: References: <554BE0E1.5030001@bluematt.me> Date: Mon, 1 Jun 2015 09:15:18 -0400 Message-ID: From: Gavin Andresen To: Alex Mizrahi Content-Type: multipart/alternative; boundary=089e013d101005e33e0517749e4e X-Spam-Score: -0.6 (/) X-Spam-Report: Spam Filtering performed by mx.sourceforge.net. See http://spamassassin.org/tag/ for more details. -1.5 SPF_CHECK_PASS SPF reports sender host as permitted sender for sender-domain 0.0 FREEMAIL_FROM Sender email is commonly abused enduser mail provider (gavinandresen[at]gmail.com) -0.0 SPF_PASS SPF: sender matches SPF record 1.0 HTML_MESSAGE BODY: HTML included in message -0.1 DKIM_VALID_AU Message has a valid DKIM or DK signature from author's domain 0.1 DKIM_SIGNED Message has a DKIM or DK signature, not necessarily valid -0.1 DKIM_VALID Message has at least one valid DKIM or DK signature 0.0 AWL AWL: Adjusted score from AWL reputation of From: address X-Headers-End: 1YzPYq-0002eC-PU Cc: Bitcoin Dev Subject: Re: [Bitcoin-development] Fwd: Block Size Increase Requirements 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: Mon, 01 Jun 2015 13:15:26 -0000 --089e013d101005e33e0517749e4e Content-Type: text/plain; charset=UTF-8 On Sun, May 31, 2015 at 6:55 PM, Alex Mizrahi wrote: > Yes, if you are on a slow network then you are at a (slight) disadvantage. >> So? >> > > Chun mentioned that his pool is on a slow network, and thus bigger blocks > give it an disadvantage. (Orphan rate is proportional to block size.) > You said that no, on contrary those who make big blocks have a disadvantage. > And now you say that yes, this disadvantage exist. > > Did you just lie to Chun? > Chun said that if somebody produced a big block it would take them at least 6 seconds to process it. He also said he has nodes outside the great firewall ("We also use Aliyun and Linode cloud services for block propagation."). So I assumed that he was talking about the "what if somebody produces a block that takes a long time to process" attack -- which doesn't work (the attacker just increases their own orphan rate). If the whole network is creating blocks that takes everybody (except the person creating the blocks) six seconds to broadcast+validate, then the increase in orphan rate is spread out over the whole network. The network-wide orphan rate goes up, everybody suffers a little (fewer blocks created over time) until the next difficulty adjustment, then the difficulty drops, then everybody is back in the same boat. If it takes six seconds to validate because of limited bandwidth, then he should connect via Matt's fast relay network, which optimize new block announcements so they take a couple orders of magnitude less bandwidth. If it takes six seconds because he's trying to validate on a raspberry pi.... then he should buy a better validating machine, and/or help test the current pending pull requests to make validation faster (e.g. https://github.com/bitcoin/bitcoin/pull/5835 or https://github.com/bitcoin/bitcoin/pull/6077 ). If Chun had six seconds of latency, and he can't pay for a lower-latency connection (or it is insanely expensive), then there's nothing he can do, he'll have to live with a higher orphan rate no matter the block size. -- -- Gavin Andresen --089e013d101005e33e0517749e4e Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
On S= un, May 31, 2015 at 6:55 PM, Alex Mizrahi <alex.mizrahi@gmail.com= > wrote:
=
Yes, if you are on a slow network = then you are at a (slight) disadvantage. So?
=

Chun mentioned that his= pool is on a slow network, and thus bigger blocks give it an disadvantage.= (Orphan rate is proportional to block size.)=C2=A0
=
<= div class=3D"gmail_quote">
You said that no, on contrary those who make= big blocks have a disadvantage.
And now you say that yes, this d= isadvantage exist.
=C2=A0
Did you just lie to Chun?

Chun said that if somebody produced a = big block it would take them at least 6 seconds to process it.

H= e also said he has nodes outside the great firewall ("We also use Aliyun and Linode cloud services f= or block
propagati= on.").

So I assumed that he was talking about t= he "what if somebody produces a block that takes a long time to proces= s" attack -- which doesn't work (the attacker just increases their= own orphan rate).

If the whole network is creating = blocks that takes everybody (except the person creating the blocks) six sec= onds to broadcast+validate, then the increase in orphan rate is spread out = over the whole network. The network-wide orphan rate goes up, everybody suf= fers a little (fewer blocks created over time) until the next difficulty ad= justment, then the difficulty drops, then everybody is back in the same boa= t.=C2=A0

If it takes six seconds to validate becau= se of limited bandwidth, then he should connect via Matt's fast relay n= etwork, which optimize new block announcements so they take a couple orders= of magnitude less bandwidth.

If it takes six se= conds because he's trying to validate on a raspberry pi.... then he sho= uld buy a better validating machine, and/or help test the current pending p= ull requests to make validation faster (e.g.=C2=A0https://github.com/bitcoin/bitcoin/pull/583= 5 or=C2=A0http= s://github.com/bitcoin/bitcoin/pull/6077 ).

If Chun had six seconds of latency, and he can= 't pay for a lower-latency connection (or it is insanely expensive), th= en there's nothing he can do, he'll have to live with a higher orph= an rate no matter the block size.

--
--
Gavin Andresen
--089e013d101005e33e0517749e4e--