From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from sog-mx-2.v43.ch3.sourceforge.com ([172.29.43.192] helo=mx.sourceforge.net) by sfs-ml-4.v29.ch3.sourceforge.com with esmtp (Exim 4.76) (envelope-from ) id 1UJWVi-0001xa-Su for bitcoin-development@lists.sourceforge.net; Sat, 23 Mar 2013 22:01:58 +0000 Received-SPF: pass (sog-mx-2.v43.ch3.sourceforge.com: domain of lavabit.com designates 72.249.41.33 as permitted sender) client-ip=72.249.41.33; envelope-from=calebdelisle@lavabit.com; helo=karen.lavabit.com; Received: from karen.lavabit.com ([72.249.41.33]) by sog-mx-2.v43.ch3.sourceforge.com with esmtp (Exim 4.76) id 1UJWVh-0007aR-7n for bitcoin-development@lists.sourceforge.net; Sat, 23 Mar 2013 22:01:58 +0000 Received: from a.earth.lavabit.com (a.earth.lavabit.com [192.168.111.10]) by karen.lavabit.com (Postfix) with ESMTP id C9A5311B989 for ; Sat, 23 Mar 2013 17:01:51 -0500 (CDT) Received: from 192.168.1.3 (c-174-62-136-247.hsd1.ct.comcast.net [174.62.136.247]) by lavabit.com with ESMTP id GVNL0JFOMO6T for ; Sat, 23 Mar 2013 17:01:51 -0500 Message-ID: <514E2649.70708@lavabit.com> Date: Sat, 23 Mar 2013 18:01:45 -0400 From: Caleb James DeLisle User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130308 Thunderbird/17.0.4 MIME-Version: 1.0 To: bitcoin-development@lists.sourceforge.net References: <1364035346.19716.YahooMailNeo@web161601.mail.bf1.yahoo.com> <201303231452.23042.luke@dashjr.org> In-Reply-To: X-Enigmail-Version: 1.4.6 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Spam-Score: -1.2 (-) X-Spam-Report: Spam Filtering performed by mx.sourceforge.net. See http://spamassassin.org/tag/ for more details. -0.0 RCVD_IN_DNSWL_NONE RBL: Sender listed at http://www.dnswl.org/, no trust [72.249.41.33 listed in list.dnswl.org] 2.9 FSL_HELO_BARE_IP_2 FSL_HELO_BARE_IP_2 -1.5 SPF_CHECK_PASS SPF reports sender host as permitted sender for sender-domain -0.0 SPF_PASS SPF: sender matches SPF record -2.5 RP_MATCHES_RCVD Envelope sender domain matches handover relay domain -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: 1UJWVh-0007aR-7n Subject: Re: [Bitcoin-development] A bitcoin UDP P2P protocol extension 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: Sat, 23 Mar 2013 22:01:59 -0000 On 03/23/2013 11:24 AM, Jeff Garzik wrote: > On Sat, Mar 23, 2013 at 10:52 AM, Luke-Jr wrote: >> On Saturday, March 23, 2013 10:42:26 AM Randy Willis wrote: >>> Introducing super-nodes with thousands of connected peers can greatly help >>> here. >> >> UDP is connectionless. >> I would hope any UDP bitcoin protocol doesn't try to emulate a connection. :/ > > It depends on the usage. Simply broadcasting a TX or INV to a remote > peer does not require a connection, clearly... but you probably want > to signal acceptance of those messages somehow. > > But other uses, like subscribing to a broadcast, does require some > notion of an association. > > In the rough draft, a parallel TCP connection with version/verack > sequence is required, and you may make use of it if a connection is > needed. > > But that is just one approach. A more robust, heavyweight UDP P2P > might be a hole-punching TCP alternative. It's up to the community > and results of experimentation. > > Bittorrent has evolved a full transfer protocol over UDP, to get > around firewalls and the like. > Bittorrent uses UDP in 2 ways and for different reasons. The tracker protocol is now UDP because large trackers are under such enormous strain from short lived HTTP connections (40Gb/s) that there have been instances of upstream routers becoming overloaded from the storm of SYN, ACK and FIN messages. UDP helps solve that. The inter-peer protocol is now UDP because TCP does not play nice in the context of bufferbloat and Bittorrent needs lots of active TCP connections to work, exacerbating the problem. In this instance Bittorrent uses a full userspace TCP stack which just sends w/ UDP. +1 for experimenting with UDP, we might learn some interesting things. It's worthwhile to actually speed test UDP v. TCP because the time to send an INV on an established TCP connection with Nagle disabled may not be significantly longer than that for sending with UDP. Also +1 for experimentation with sending a small transaction instead of an INV, if INVs are not being grouped because we want the fastest possible network propagation, they are mostly overhead anyway. If b/w is more important than propagation speed then of course TCP/Nagle is the way to go. Thanks, Caleb