From owner-freebsd-net@freebsd.org Mon Jun 24 15:00:53 2019 Return-Path: Delivered-To: freebsd-net@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id DD21B15D0211 for ; Mon, 24 Jun 2019 15:00:53 +0000 (UTC) (envelope-from freebsd-rwg@gndrsh.dnsmgr.net) Received: from gndrsh.dnsmgr.net (br1.CN84in.dnsmgr.net [69.59.192.140]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id CFB2F71C54 for ; Mon, 24 Jun 2019 15:00:52 +0000 (UTC) (envelope-from freebsd-rwg@gndrsh.dnsmgr.net) Received: from gndrsh.dnsmgr.net (localhost [127.0.0.1]) by gndrsh.dnsmgr.net (8.13.3/8.13.3) with ESMTP id x5OF0nDT044102; Mon, 24 Jun 2019 08:00:49 -0700 (PDT) (envelope-from freebsd-rwg@gndrsh.dnsmgr.net) Received: (from freebsd-rwg@localhost) by gndrsh.dnsmgr.net (8.13.3/8.13.3/Submit) id x5OF0nRT044101; Mon, 24 Jun 2019 08:00:49 -0700 (PDT) (envelope-from freebsd-rwg) From: "Rodney W. Grimes" Message-Id: <201906241500.x5OF0nRT044101@gndrsh.dnsmgr.net> Subject: Re: Odd TCP ECN related bahavior In-Reply-To: <777f12f5-3c58-a6ef-5a92-df6be9372ec6@gmail.com> To: "Jukka A. Ukkonen" Date: Mon, 24 Jun 2019 08:00:49 -0700 (PDT) CC: freebsd-net@freebsd.org X-Mailer: ELM [version 2.4ME+ PL121h (25)] MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=US-ASCII X-Rspamd-Queue-Id: CFB2F71C54 X-Spamd-Bar: ++ Authentication-Results: mx1.freebsd.org X-Spamd-Result: default: False [2.19 / 15.00]; ARC_NA(0.00)[]; NEURAL_HAM_MEDIUM(-0.02)[-0.020,0]; FROM_HAS_DN(0.00)[]; TO_DN_SOME(0.00)[]; NEURAL_SPAM_SHORT(0.71)[0.709,0]; MIME_GOOD(-0.10)[text/plain]; RCVD_TLS_LAST(0.00)[]; DMARC_NA(0.00)[dnsmgr.net]; AUTH_NA(1.00)[]; RCVD_COUNT_THREE(0.00)[3]; TO_MATCH_ENVRCPT_SOME(0.00)[]; MX_GOOD(-0.01)[cached: gndrsh.dnsmgr.net]; RCPT_COUNT_TWO(0.00)[2]; NEURAL_SPAM_LONG(0.57)[0.570,0]; R_SPF_NA(0.00)[]; FREEMAIL_TO(0.00)[gmail.com]; FROM_EQ_ENVFROM(0.00)[]; R_DKIM_NA(0.00)[]; MIME_TRACE(0.00)[0:+]; ASN(0.00)[asn:13868, ipnet:69.59.192.0/19, country:US]; MID_RHS_MATCH_FROM(0.00)[]; IP_SCORE(0.04)[ip: (0.14), ipnet: 69.59.192.0/19(0.07), asn: 13868(0.05), country: US(-0.06)] X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 24 Jun 2019 15:00:54 -0000 > > Hi all, > > I am not on this mailing list. So, all responses should be sent > to my personal address. > > I just noticed somewhat confusing network behavior when I was > using wireshark to understand why certain connections have been > unexpectedly slow. > > My 11.3 stable (latest update 2019-06-23) seems to do this > according to wireshark... > > .... ..00 = Explicit Congestion Notification: Not ECN-Capable Transport (0) You only show 1 packet, and without the type of that packet I can not tell if this is an error in the code or simply that you captured one of the packets that does not marked with ECN bits even in an ECN flow Note also that ECN is negotiated on a per TCP connection, not on every single packet. > > My system has this set, though... > > net.inet.tcp.ecn.enable: 1 So ecn should be negotiated in both directions. > > At the same time the peer system was reporting ECN capability... > > .... ..10 = Explicit Congestion Notification: ECN-Capable Transport > codepoint '10' (2) > > Apparently increasing the value in... > > net.inet.tcp.ecn.maxretries > > doesn't help. > > What should I make of this? Is the ECN implementation in 11.3 somehow > faulty or is this something more down to earth? If it is I would certainly like to now asap, > --jau -- Rod Grimes rgrimes@freebsd.org