<html><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class="">Miles made the claim that BT is “more efficient” than unicast because it somehow becomes "EFFECTIVELY multicast - avoiding redundant traffic when more than one destination is downloading the same file, at the same time.” I don’t believe this is true. <div class=""><br class=""></div><div class="">BT is a UDP-based protocol that senses queuing delays and defers more aggressively than TCP when they happen. Here’s the protocol spec: <a href="http://www.bittorrent.org/beps/bep_0003.html" class="">http://www.bittorrent.org/beps/bep_0003.html</a>, if you can find any redundancy reduction in it please point it out.<div class=""><br class=""></div><div class="">RB<br class=""><div><br class=""><blockquote type="cite" class=""><div class="">On Feb 26, 2019, at 2:16 PM, Guy Almes <<a href="mailto:galmes@tamu.edu" class="">galmes@tamu.edu</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><div class="">Richard,<br class=""> If you do multicast at the network layer, you get IP multicast, Steve Deering's thesis project that escaped from the lab and has challenged network engineers ever since.<br class=""> But if you do multicast at the application layer, you get lots of (IP) unicast traffic, but with some of the properties of IP multicast and also with some of the advantages of TCP and without the challenging routing issues of IP multicast. Examples include BitTorrent, Unidata's LDM/IDD software, and the USENET netnews utility.<br class=""> Oh, and you can also do multicast at the Ethernet level. Historically, it was the multicast feature of the then-new 10Mb/s Ethernet that triggered Deering's considering the possibility of multicast at the network layer.<br class=""><br class=""> So IMHO the term multicast can be used appropriately without necessarily referring to network-layer IP multicast.<br class=""><br class=""> Back to the primary topic,<br class=""><span class="Apple-tab-span" style="white-space:pre"> </span>-- Guy<br class=""><br class="">On 2/26/19 15:35, Richard Bennett wrote:<br class=""><blockquote type="cite" class="">Perhaps you can explain that the term "EFFECTIVELY multicast” means to you, and how it applies to BitTorrent. Every time I’ve looked at it in Wireshark I see nothing but unicast.<br class="">RB<br class=""><blockquote type="cite" class="">On Feb 26, 2019, at 10:01 AM, Miles Fidelman <<a href="mailto:mfidelman@meetinghouse.net" class="">mfidelman@meetinghouse.net</a> <<a href="mailto:mfidelman@meetinghouse.net" class="">mailto:mfidelman@meetinghouse.net</a>>> wrote:<br class=""><br class="">Well, that's not how it's supposed to work. Or claimed to work.<br class=""><br class="">On 2/25/19 8:27 PM, Richard Bennett wrote:<br class=""><blockquote type="cite" class="">Naw, it’s all unicast with plenty of redundant traffic moving along long routes.<br class=""><br class=""><blockquote type="cite" class="">On Feb 25, 2019, at 5:49 PM, Miles Fidelman <<a href="mailto:mfidelman@meetinghouse.net" class="">mfidelman@meetinghouse.net</a> <<a href="mailto:mfidelman@meetinghouse.net" class="">mailto:mfidelman@meetinghouse.net</a>>> wrote:<br class=""><br class="">That's not what anybody said. It's EFFECTIVELY multicast - avoiding redundant traffic when more than one destination is downloading the same file, at the same time. That's its whole point. (Or as someone else put it, it's a caching mechanism.)<br class=""><br class="">Miles<br class=""><br class="">On 2/25/19 4:24 PM, Richard Bennett wrote:<br class=""><blockquote type="cite" class="">Bittorrent doesn’t use multicast.<br class=""><br class=""><blockquote type="cite" class="">On Feb 25, 2019, at 1:42 PM, Miles Fidelman <<a href="mailto:mfidelman@meetinghouse.net" class="">mfidelman@meetinghouse.net</a> <<a href="mailto:mfidelman@meetinghouse.net" class="">mailto:mfidelman@meetinghouse.net</a>>> wrote:<br class=""><br class="">Well yes, but torrent is a distribution mechanism - it's not an infrastructure for maintaining or mirroring files. It's essentially another, sometimes more efficient, option for click-to-download (e.g., ftp, http, bittorrent). And it's only more efficient if multiple people are downloading at the same time.<br class=""><br class="">Miles<br class=""><br class="">On 2/25/19 12:28 PM, Richard Bennett wrote:<br class=""><blockquote type="cite" class="">No, Bittorrent uses DHTs and accesses as many copies of a given file as users choose to share. It has to be running to serve files, however.<br class=""><br class="">RB<br class=""><br class=""><blockquote type="cite" class="">On Feb 25, 2019, at 9:59 AM, Miles Fidelman <<a href="mailto:mfidelman@meetinghouse.net" class="">mfidelman@meetinghouse.net</a> <<a href="mailto:mfidelman@meetinghouse.net" class="">mailto:mfidelman@meetinghouse.net</a>>> wrote:<br class=""><br class="">On 2/24/19 9:53 PM, John Levine wrote:<br class=""><br class=""><blockquote type="cite" class=""><blockquote type="cite" class="">That's what I find intriguing about my Benevolent BotNet notion. Rather<br class="">than depending on finding an institution interested in, competent at,<br class="">and willing to save history, and hoping that it has longevity, you rely<br class="">on a network of volunteers to provide that survivable infrastructure by<br class="">volunteering their excess computing resources.<br class=""></blockquote>Hi again. Please look at Bittorrent and tell us how it is different<br class="">from what you're proposing.<br class=""><br class="">Bittorrent has the advantage of already existing and being deployed<br class="">all over the world. It's notorious for pirated music but it's also<br class="">widely used for sharing linux distributions and the like.<br class=""><br class=""></blockquote>Bit torrent is transient. It's more like an ad-hoc multi-cast<br class="">streaming. When nobody is downloading, there may be only one copy of<br class="">the file.<br class=""><br class="">Now gnutella, and some of the other P2P file sharing systems - that<br class="">replicate copies, or distribute files across a distributed hash table -<br class="">that's another story entirely.<br class=""><br class="">-- <br class="">In theory, there is no difference between theory and practice.<br class="">In practice, there is. .... Yogi Berra<br class=""><br class="">_______<br class="">internet-history mailing list<br class=""><a href="mailto:internet-history@postel.org" class="">internet-history@postel.org</a> <<a href="mailto:internet-history@postel.org" class="">mailto:internet-history@postel.org</a>><br class=""><a href="http://mailman.postel.org/mailman/listinfo/internet-history" class="">http://mailman.postel.org/mailman/listinfo/internet-history</a><br class="">Contact list-owner@postel.org for assistance.<br class=""></blockquote><br class="">—<br class="">Richard Bennett<br class="">High Tech Forum <<a href="https://urldefense.proofpoint.com/v2/url?u=http-3A__hightechforum.org_&d=DwMFaQ&c=ODFT-G5SujMiGrKuoJJjVg&r=R09ttqQsnYaGPTsoYTZvLQ&m=L_GuN-mjLyb3nq7400xTV8D7FqWBXEnvfamqUrl6ys4&s=5sVVbAboWDOn4Em7VNOaohMIw5oSQNOpdgpOgTEb2co&e=" class="">https://urldefense.proofpoint.com/v2/url?u=http-3A__hightechforum.org_&d=DwMFaQ&c=ODFT-G5SujMiGrKuoJJjVg&r=R09ttqQsnYaGPTsoYTZvLQ&m=L_GuN-mjLyb3nq7400xTV8D7FqWBXEnvfamqUrl6ys4&s=5sVVbAboWDOn4Em7VNOaohMIw5oSQNOpdgpOgTEb2co&e=</a>> Founder<br class="">Ethernet & Wi-Fi standards co-creator<br class=""><br class="">Internet Policy Consultant<br class=""><br class=""></blockquote>-- <br class="">In theory, there is no difference between theory and practice.<br class="">In practice, there is. .... Yogi Berra<br class=""></blockquote><br class="">—<br class="">Richard Bennett<br class="">High Tech Forum <<a href="https://urldefense.proofpoint.com/v2/url?u=http-3A__hightechforum.org_&d=DwMFaQ&c=ODFT-G5SujMiGrKuoJJjVg&r=R09ttqQsnYaGPTsoYTZvLQ&m=L_GuN-mjLyb3nq7400xTV8D7FqWBXEnvfamqUrl6ys4&s=5sVVbAboWDOn4Em7VNOaohMIw5oSQNOpdgpOgTEb2co&e=" class="">https://urldefense.proofpoint.com/v2/url?u=http-3A__hightechforum.org_&d=DwMFaQ&c=ODFT-G5SujMiGrKuoJJjVg&r=R09ttqQsnYaGPTsoYTZvLQ&m=L_GuN-mjLyb3nq7400xTV8D7FqWBXEnvfamqUrl6ys4&s=5sVVbAboWDOn4Em7VNOaohMIw5oSQNOpdgpOgTEb2co&e=</a>> Founder<br class="">Ethernet & Wi-Fi standards co-creator<br class=""><br class="">Internet Policy Consultant<br class=""><br class=""></blockquote>-- <br class="">In theory, there is no difference between theory and practice.<br class="">In practice, there is. .... Yogi Berra<br class="">_______<br class="">internet-history mailing list<br class=""><a href="mailto:internet-history@postel.org" class="">internet-history@postel.org</a> <<a href="mailto:internet-history@postel.org" class="">mailto:internet-history@postel.org</a>><br class=""><a href="http://mailman.postel.org/mailman/listinfo/internet-history" class="">http://mailman.postel.org/mailman/listinfo/internet-history</a><br class="">Contact list-owner@postel.org for assistance.<br class=""></blockquote><br class="">—<br class="">Richard Bennett<br class="">High Tech Forum <<a href="https://urldefense.proofpoint.com/v2/url?u=http-3A__hightechforum.org_&d=DwMFaQ&c=ODFT-G5SujMiGrKuoJJjVg&r=R09ttqQsnYaGPTsoYTZvLQ&m=L_GuN-mjLyb3nq7400xTV8D7FqWBXEnvfamqUrl6ys4&s=5sVVbAboWDOn4Em7VNOaohMIw5oSQNOpdgpOgTEb2co&e=" class="">https://urldefense.proofpoint.com/v2/url?u=http-3A__hightechforum.org_&d=DwMFaQ&c=ODFT-G5SujMiGrKuoJJjVg&r=R09ttqQsnYaGPTsoYTZvLQ&m=L_GuN-mjLyb3nq7400xTV8D7FqWBXEnvfamqUrl6ys4&s=5sVVbAboWDOn4Em7VNOaohMIw5oSQNOpdgpOgTEb2co&e=</a>> Founder<br class="">Ethernet & Wi-Fi standards co-creator<br class=""><br class="">Internet Policy Consultant<br class=""><br class=""></blockquote>-- <br class="">In theory, there is no difference between theory and practice.<br class="">In practice, there is. .... Yogi Berra<br class="">_______<br class="">internet-history mailing list<br class=""><a href="mailto:internet-history@postel.org" class="">internet-history@postel.org</a> <<a href="mailto:internet-history@postel.org" class="">mailto:internet-history@postel.org</a>><br class=""><a href="http://mailman.postel.org/mailman/listinfo/internet-history" class="">http://mailman.postel.org/mailman/listinfo/internet-history</a><br class="">Contact list-owner@postel.org for assistance.<br class=""></blockquote>—<br class="">Richard Bennett<br class="">High Tech Forum <<a href="https://urldefense.proofpoint.com/v2/url?u=http-3A__hightechforum.org&d=DwMFaQ&c=ODFT-G5SujMiGrKuoJJjVg&r=R09ttqQsnYaGPTsoYTZvLQ&m=L_GuN-mjLyb3nq7400xTV8D7FqWBXEnvfamqUrl6ys4&s=LZmy5fQZwLAb8wV6BIqZQ4PoPWOZ9QTG2meSKhwn4gc&e=" class="">https://urldefense.proofpoint.com/v2/url?u=http-3A__hightechforum.org&d=DwMFaQ&c=ODFT-G5SujMiGrKuoJJjVg&r=R09ttqQsnYaGPTsoYTZvLQ&m=L_GuN-mjLyb3nq7400xTV8D7FqWBXEnvfamqUrl6ys4&s=LZmy5fQZwLAb8wV6BIqZQ4PoPWOZ9QTG2meSKhwn4gc&e=</a>> Founder<br class="">Ethernet & Wi-Fi standards co-creator<br class="">Internet Policy Consultant<br class="">_______<br class="">internet-history mailing list<br class=""><a href="mailto:internet-history@postel.org" class="">internet-history@postel.org</a><br class="">http://mailman.postel.org/mailman/listinfo/internet-history<br class="">Contact list-owner@postel.org for assistance.<br class=""></blockquote></div></div></blockquote></div><br class=""><div class="">
<div style="color: rgb(0, 0, 0); letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class="">—<br class=""><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class="">Richard Bennett<br class=""><a href="http://hightechforum.org" class="">High Tech Forum</a> Founder</div><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class="">Ethernet & Wi-Fi standards co-creator</div><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><br class=""></div><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class="">Internet Policy Consultant</div></div></div>
</div>
<br class=""></div></div></body></html>