From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from sog-mx-4.v43.ch3.sourceforge.com ([172.29.43.194] helo=mx.sourceforge.net) by sfs-ml-3.v29.ch3.sourceforge.com with esmtp (Exim 4.76) (envelope-from ) id 1XCzcS-0005qb-S4 for bitcoin-development@lists.sourceforge.net; Thu, 31 Jul 2014 23:18:44 +0000 Received-SPF: pass (sog-mx-4.v43.ch3.sourceforge.com: domain of gmail.com designates 209.85.220.171 as permitted sender) client-ip=209.85.220.171; envelope-from=gmaxwell@gmail.com; helo=mail-vc0-f171.google.com; Received: from mail-vc0-f171.google.com ([209.85.220.171]) by sog-mx-4.v43.ch3.sourceforge.com with esmtps (TLSv1:RC4-SHA:128) (Exim 4.76) id 1XCzcR-00057V-Pq for bitcoin-development@lists.sourceforge.net; Thu, 31 Jul 2014 23:18:44 +0000 Received: by mail-vc0-f171.google.com with SMTP id hq11so5464695vcb.16 for ; Thu, 31 Jul 2014 16:18:38 -0700 (PDT) MIME-Version: 1.0 X-Received: by 10.52.69.172 with SMTP id f12mr1567193vdu.9.1406848718260; Thu, 31 Jul 2014 16:18:38 -0700 (PDT) Received: by 10.52.187.132 with HTTP; Thu, 31 Jul 2014 16:18:38 -0700 (PDT) In-Reply-To: References: Date: Thu, 31 Jul 2014 16:18:38 -0700 Message-ID: From: Gregory Maxwell To: Kaz Wesley Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-Spam-Score: -1.6 (-) 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 (gmaxwell[at]gmail.com) -0.0 SPF_PASS SPF: sender matches SPF record -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 X-Headers-End: 1XCzcR-00057V-Pq Cc: Bitcoin Dev Subject: Re: [Bitcoin-development] Squashing redundant tx data in blocks on the wire 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, 31 Jul 2014 23:18:45 -0000 On Thu, Jul 31, 2014 at 3:27 PM, Kaz Wesley wrote: >> the FEC still lets you fill in the missing transactions without knowing = in advance all that will be missing. > > I don't see why we need to solve that problem, since the protocol > already involves exchanging the information necessary to determine > (with some false positives) what a peer is missing, and needs to > continue doing so regardless of how blocks are transmitted. False positives, and if you have more than one peer=E2=80=94 false negative= s. (or a rule for what you must keep which is conservative in order to avoid creating huge storage requirements=E2=80=94 but then also has false negatives). > As far as I can tell, channel memory sparseblocks achieve most of the > possible bandwidth savings, and when FEC-based mempool synchronization > is implemented its benefits can be applied to the sparseblocks by > resetting the channel memory to the mutual mempool state each time > mempool differences are exchanged. Am I missing a benefit to doing FEC > at block forwarding time that can't be realized by FEC-based mempool > synchronization, implemented separately from channel-memory based > index-coding? Yes, minimizing latency in the face of multiple peers. Otherwise no. And certantly no reason to to implement something simple firs= t.