From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pb0-f43.google.com (mail-pb0-f43.google.com [209.85.160.43]) (using TLSv1 with cipher RC4-SHA (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority" (verified OK)) by huchra.bufferbloat.net (Postfix) with ESMTPS id E1980200B49 for ; Sun, 5 Aug 2012 09:53:54 -0700 (PDT) Received: by pbcwz7 with SMTP id wz7so9066355pbc.16 for ; Sun, 05 Aug 2012 09:53:54 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=content-type:mime-version:subject:from:in-reply-to:date:cc :message-id:references:to:x-mailer; bh=mtMbucDIeG2xyE8Z4FBsY20THwnhByn1y3QQtjQp2rY=; b=LVY6BP1rZsk0KwPYCEpc+Ix3CXo4GryR4cdlQntbNrJ+ThhlMro3vAGPZLF0DGVe9q 2BOKZqc5KCLPjXOFj/C7x1l6epYEcMb2tCMaRbRrE7ddEaypcm609HU1M6yxSj7w0cG/ rwVzdax8booP8a/ZvEHGkdVxetyths/fCl1MRdp/aR5sLSI1HvpV2kBmZGc0/4WejVJd UWAemVr+2sdDiEC9VqwjARBWQOZSzfcDKgNSe55ilGq2tI9GOsHftrEEptcd1fFN/7iy htbjDdd8wVsFupddp8u8gdTVSY/JP7eedyreB8NRB0V/uYbcgn8fhM2GJ7EbvT8BJnac o+tg== Received: by 10.68.213.234 with SMTP id nv10mr12722339pbc.56.1344185634233; Sun, 05 Aug 2012 09:53:54 -0700 (PDT) Received: from [192.168.1.104] (74-95-2-169-SFBA.hfc.comcastbusiness.net. [74.95.2.169]) by mx.google.com with ESMTPS id pe2sm3714442pbc.59.2012.08.05.09.53.52 (version=TLSv1/SSLv3 cipher=OTHER); Sun, 05 Aug 2012 09:53:52 -0700 (PDT) Content-Type: multipart/signed; boundary="Apple-Mail=_C9E17FB8-BB4D-4A3C-A723-D608F4DAFD80"; protocol="application/pkcs7-signature"; micalg=sha1 Mime-Version: 1.0 (Mac OS X Mail 6.0 \(1485\)) From: Andrew McGregor In-Reply-To: <1344144623.9299.1557.camel@edumazet-glaptop> Date: Sun, 5 Aug 2012 09:53:49 -0700 Message-Id: References: <1344048299-26267-1-git-send-email-dave.taht@bufferbloat.net> <1344062738.9299.1453.camel@edumazet-glaptop> <501D99C4.20902@pollere.com> <7EB59257-1A8E-4567-8AD3-5016594565CC@gmail.com> <1344144623.9299.1557.camel@edumazet-glaptop> To: Eric Dumazet X-Mailer: Apple Mail (2.1485) Cc: codel@lists.bufferbloat.net Subject: Re: [Codel] [RFC PATCH] codel: ecn mark at target X-BeenThere: codel@lists.bufferbloat.net X-Mailman-Version: 2.1.13 Precedence: list List-Id: CoDel AQM discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 05 Aug 2012 16:53:55 -0000 --Apple-Mail=_C9E17FB8-BB4D-4A3C-A723-D608F4DAFD80 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=us-ascii Well, there's a lot of people at the IETF who really want to do other = things with ECN, but it seems like the simple version is far too = aggressive. So, I think the desirable properties are something like: 1) Allow ECN flows to achieve the same or slightly higher throughput to = maintain an incentive to deploy it. 2) Still drop ECN flows eventually to avoid too much queue buildup. 3) Account somehow for the fact that marking takes longer to control the = queue (but we don't know how much longer). Maybe mark ECN instead of dropping, but if we end up trying to mark/drop = twice in one round, drop the later packets? Oh, and ECN nonce deployment is negligible, to the extent that there are = proposals in the IETF to reuse the bits for other things, and there is = no pushback on that. Andrew On 4/08/2012, at 10:30 PM, Eric Dumazet wrote: > On Sat, 2012-08-04 at 20:06 -0700, Andrew McGregor wrote: >> Well, thanks Eric for trying it. >>=20 >> Hmm. How was I that wrong? Because I was supporting that idea. >>=20 >> Time to think. >=20 > No problem Andrew ;) >=20 > Its seems ECN is not well enough understood. >=20 > ECN marking a packet has the same effect for the sender : reducing = cwnd > exactly like a packet drop. Only difference is avoiding the > retransmit[s]. >=20 > It cannot be used only to send a 'small' warning, while other = competing > non ECN flows have no signal. >=20 > As far as packet schedulers are concerned, there should be no = difference > in ECN marking and dropping a packet. I believe linux packet = schedulers > are fine in this area. >=20 > Now, there are fundamental issues with ECN itself, out of Codel scope, > thats for sure. >=20 > How widely has been RFC 3540 deployed, anybody knows ? >=20 >=20 >=20 --Apple-Mail=_C9E17FB8-BB4D-4A3C-A723-D608F4DAFD80 Content-Disposition: attachment; filename=smime.p7s Content-Type: application/pkcs7-signature; name=smime.p7s Content-Transfer-Encoding: base64 MIAGCSqGSIb3DQEHAqCAMIACAQExCzAJBgUrDgMCGgUAMIAGCSqGSIb3DQEHAQAAoIIFLjCCBSow ggQSoAMCAQICEQDMQ2ZKvgsUYA5oQg5SjWfVMA0GCSqGSIb3DQEBBQUAMIGTMQswCQYDVQQGEwJH QjEbMBkGA1UECBMSR3JlYXRlciBNYW5jaGVzdGVyMRAwDgYDVQQHEwdTYWxmb3JkMRowGAYDVQQK ExFDT01PRE8gQ0EgTGltaXRlZDE5MDcGA1UEAxMwQ09NT0RPIENsaWVudCBBdXRoZW50aWNhdGlv biBhbmQgU2VjdXJlIEVtYWlsIENBMB4XDTExMTAwMTAwMDAwMFoXDTEyMDkzMDIzNTk1OVowJTEj MCEGCSqGSIb3DQEJARYUYW5kcmV3bWNnckBnbWFpbC5jb20wggEiMA0GCSqGSIb3DQEBAQUAA4IB DwAwggEKAoIBAQC+buTRxzSXTQmMyUqaokLJit3xU5WVudxHijhKbGRSTgJ867L/v8+rNhSoFwCV MdKIu/M7apWgGkkA+MT/LjDFj63jLT+4nTTLIojXZdoezbpp/rQ2ViSbi54AjhZBQ5X+yH2xcXmG KpDhZjeZC1bvKNvBtdOHCAcrx1Ys1BNj+AhwridEX/KD0cq5xSsJhjDggF6XSUOsaiqBHR6fiQMi 7gH8EuFBh83oklb/pdreg1fQ7gKJk/Me/atIbE1gtbIR88oaCtXoHfZxgkFwagwMtBHdkxN+wcZy 9xx78el9Lxrjx2nMq50hRlj/bqg/m4rSox7//DKfx7bfKNZAiSMDAgMBAAGjggHkMIIB4DAfBgNV HSMEGDAWgBR6E04AdFvGeGNkJ8Ev4qBbvHnFezAdBgNVHQ4EFgQUXOXqNkq6sNbrD8B41dPko8Gs JucwDgYDVR0PAQH/BAQDAgWgMAwGA1UdEwEB/wQCMAAwIAYDVR0lBBkwFwYIKwYBBQUHAwQGCysG AQQBsjEBAwUCMBEGCWCGSAGG+EIBAQQEAwIFIDBGBgNVHSAEPzA9MDsGDCsGAQQBsjEBAgEBATAr MCkGCCsGAQUFBwIBFh1odHRwczovL3NlY3VyZS5jb21vZG8ubmV0L0NQUzBXBgNVHR8EUDBOMEyg SqBIhkZodHRwOi8vY3JsLmNvbW9kb2NhLmNvbS9DT01PRE9DbGllbnRBdXRoZW50aWNhdGlvbmFu ZFNlY3VyZUVtYWlsQ0EuY3JsMIGIBggrBgEFBQcBAQR8MHowUgYIKwYBBQUHMAKGRmh0dHA6Ly9j cnQuY29tb2RvY2EuY29tL0NPTU9ET0NsaWVudEF1dGhlbnRpY2F0aW9uYW5kU2VjdXJlRW1haWxD QS5jcnQwJAYIKwYBBQUHMAGGGGh0dHA6Ly9vY3NwLmNvbW9kb2NhLmNvbTAfBgNVHREEGDAWgRRh bmRyZXdtY2dyQGdtYWlsLmNvbTANBgkqhkiG9w0BAQUFAAOCAQEAgmf81vnsAnbcmIAyyqvEKxAK jRHerfreN10DK1ISkUJ//U4uffQV8sAGDtyIErzVFsW6NYRmFCMSE20M1ffbFpWUmXCtm/YTlkf1 5STVjTMNshDzMDhpjx99Z2J5RBJPZpXjwmpQnfKwB7zft9TcUSIb9FvZm33EKdF/XlS12U4Q9fsj 2shZf88RituX2+fCWfHoTWiFEhFUkLRtWf1YpgHpEXr82nqROxs/aWNlqtLnwTTu2ULr/WpUaRDs kom8gFZkMgw5kRfLpSXRrCFSORsZzkH2ooRxaJY7wMwZaCUS1am9DuwVy7gehoc3ZsjsDkMObZeu kx7Cg7GxIkgo+zGCA64wggOqAgEBMIGpMIGTMQswCQYDVQQGEwJHQjEbMBkGA1UECBMSR3JlYXRl ciBNYW5jaGVzdGVyMRAwDgYDVQQHEwdTYWxmb3JkMRowGAYDVQQKExFDT01PRE8gQ0EgTGltaXRl ZDE5MDcGA1UEAxMwQ09NT0RPIENsaWVudCBBdXRoZW50aWNhdGlvbiBhbmQgU2VjdXJlIEVtYWls IENBAhEAzENmSr4LFGAOaEIOUo1n1TAJBgUrDgMCGgUAoIIB2TAYBgkqhkiG9w0BCQMxCwYJKoZI hvcNAQcBMBwGCSqGSIb3DQEJBTEPFw0xMjA4MDUxNjUzNDlaMCMGCSqGSIb3DQEJBDEWBBRPtqfY HMOLOnr4Fm2M6TWEri1R6TCBugYJKwYBBAGCNxAEMYGsMIGpMIGTMQswCQYDVQQGEwJHQjEbMBkG A1UECBMSR3JlYXRlciBNYW5jaGVzdGVyMRAwDgYDVQQHEwdTYWxmb3JkMRowGAYDVQQKExFDT01P RE8gQ0EgTGltaXRlZDE5MDcGA1UEAxMwQ09NT0RPIENsaWVudCBBdXRoZW50aWNhdGlvbiBhbmQg U2VjdXJlIEVtYWlsIENBAhEAzENmSr4LFGAOaEIOUo1n1TCBvAYLKoZIhvcNAQkQAgsxgayggakw gZMxCzAJBgNVBAYTAkdCMRswGQYDVQQIExJHcmVhdGVyIE1hbmNoZXN0ZXIxEDAOBgNVBAcTB1Nh bGZvcmQxGjAYBgNVBAoTEUNPTU9ETyBDQSBMaW1pdGVkMTkwNwYDVQQDEzBDT01PRE8gQ2xpZW50 IEF1dGhlbnRpY2F0aW9uIGFuZCBTZWN1cmUgRW1haWwgQ0ECEQDMQ2ZKvgsUYA5oQg5SjWfVMA0G CSqGSIb3DQEBAQUABIIBAKnXRasBJQuHe7ctbH6LdimhsdcHE+OgIVcm++9pojHczYY+PPLckezr 9XzCEDt12MPQUBLiJ49jhcpsnTsfYkYQj9Bx6qBPHZ+ZrG4fC6MdVybWMoCKqMAf6DTZ+dvJDzaf 5lDiyY794Wx7gI69eVmYJlAssHikhrRGYo2RQJnw03989V5y+tJL0+heCGjZlM2L7gbSz0Yd7//m D+erH3I/2eH+TCogKYExLdt4gywF6BSkmvb9NCKa/xDOE36udVGczfQEstglfne9SpqJBze3Mr5S LI44Bft1z4hxdvXZT9Tg8qmDMAjY2zY5qJvvJpu0P64yP2VOMlY4WqHI8kMAAAAAAAA= --Apple-Mail=_C9E17FB8-BB4D-4A3C-A723-D608F4DAFD80--