From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.toke.dk (mail.toke.dk [IPv6:2a00:7660:6da:2001::664]) (using TLSv1.2 with cipher ADH-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.bufferbloat.net (Postfix) with ESMTPS id AE03C3B29D for ; Wed, 13 Nov 2019 05:45:53 -0500 (EST) From: Toke =?utf-8?Q?H=C3=B8iland-J=C3=B8rgensen?= DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=toke.dk; s=20161023; t=1573641951; bh=AaNBCsyGuxyiY2AELKDFBVgM466vFjXhGGHBnUpMvjY=; h=From:To:Cc:Subject:In-Reply-To:References:Date:From; b=xqthJQEAMVmErVpzwDGP4zLnWYEwwW6Kqmen9vmQIitUCXPpFwCXe3SVFhOi39imf TEEn4c9O4Qu1sPEdlfdgFnPBc2J1toGNp+5Fz+gyhzOQeLRG088VIQc24KdohJEALH N/MZs+sjg+4E8wMn8Z+cFzpHccfPcKlO+HalX8haYkD4+EDH9S/Pok8/m38FTGT3LJ jhEyMSWlFLLprRoExBESB4o64bczPFVHttoQSER6TWtWgYCE5emRvPz5GTv+JtkIaq n8dRz//4Ez57tNshi15n9OdmuQGawteVJIdFXF6iG4R18sdByXJBOzPI26MLlIfZRe 4aBzKkG7oBhZw== To: Luca Muscariello , "Rodney W. Grimes" <4bone@gndrsh.dnsmgr.net> Cc: ECN-Sane , Rich Brown In-Reply-To: References: <878sokpxdl.fsf@toke.dk> <201911130004.xAD04Vx6041534@gndrsh.dnsmgr.net> Date: Wed, 13 Nov 2019 11:45:51 +0100 X-Clacks-Overhead: GNU Terry Pratchett Message-ID: <8736esoy00.fsf@toke.dk> MIME-Version: 1.0 Content-Type: text/plain Subject: Re: [Ecn-sane] Meanwhile, over on NANOG... X-BeenThere: ecn-sane@lists.bufferbloat.net X-Mailman-Version: 2.1.20 Precedence: list List-Id: Discussion of explicit congestion notification's impact on the Internet List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 13 Nov 2019 10:45:53 -0000 Luca Muscariello writes: > TCP anycast fails in this case and I would not blame the load balancer for > that. > Some people will have a different opinion on that. > > The current Internet just does not support well these use cases. > > At the same time this DNS service is supposed to be used in a different > way. So we may even blame the user? Toke in this case ? > > DNS anycast works as long as it uses UDP. > The IP address returned by the resolver should be unicast and TCP should > run over unicast addresses. > > Toke, Looks like you are doing an HTTP GET directly toward an anycast > address. This is where things are supposed to break and they break. I was just using 1.1.1.1 as a convenient example because it's easy to type. I get the same behaviour to an actual web site hosted on Cloudflare (which is how I discovered it in the first place). Cloudflare makes heavy use of anycast, including to its HTTP endpoints. > If you traceroute over unicast addresses you should see the load > balancer providing stickiness. As I replied to Rod, the non-stickiness was indeed user error on my part. The problem is that the load balancer is hashing on headers including the ECN bits. I guess I'll go reply to the NANOG thread... :) -Toke