From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from vps.slashdirt.org (vps.slashdirt.org [144.91.108.218]) (using TLSv1.2 with cipher ADH-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.bufferbloat.net (Postfix) with ESMTPS id 900C33CB47 for ; Fri, 13 Dec 2019 08:43:30 -0500 (EST) Received: from mail.zigoo.net (localhost [127.0.0.1]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by vps.slashdirt.org (Postfix) with ESMTPSA id 8374E603EA for ; Fri, 13 Dec 2019 14:43:29 +0100 (CET) DKIM-Filter: OpenDKIM Filter v2.11.0 vps.slashdirt.org 8374E603EA DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=slashdirt.org; s=mail; t=1576244609; bh=Q6CEMALZbs7jbbIZi0NeYYoHNtq9vGobFbOsaL+jdlY=; h=Date:From:Subject:To:From; b=LBjv10JIOZz4EeyNT0iTrNNhOH1tSipv23rYUPpXF7kI8GaIAaCy+WeisMs83KVJD NvZnJfYlqZkiqpZRjccAI3lzaAWP527TZfw9YtNafVYrc9EUR1YSsNmmAGwYQjj5sK y9SbRjjf+4UnCb+KAAVN87ootXcFY4uJYe19jNsk= MIME-Version: 1.0 Date: Fri, 13 Dec 2019 13:43:29 +0000 Content-Type: multipart/alternative; boundary="--=_RainLoop_603_178428716.1576244609" X-Mailer: RainLoop/1.13.0 From: "Thibaut" Message-ID: <1d359153abfc413b4f61c647437427d6@slashdirt.org> To: cake@lists.bufferbloat.net Subject: [Cake] Trouble with CAKE X-BeenThere: cake@lists.bufferbloat.net X-Mailman-Version: 2.1.20 Precedence: list List-Id: Cake - FQ_codel the next generation List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 13 Dec 2019 13:43:30 -0000 ----=_RainLoop_603_178428716.1576244609 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Hi list,=0A=0AI've been using CAKE on my DSL-connected Linux router for t= he last few years, and it worked well until very recently. Two things hap= pened:=0A=0A1) My ISP (French "Free") switched my DSLAM to native IPv6, w= hich for the time being means that I had to revert to using their set-top= -box (Freebox) instead of the VDSL2 model I was using in bridge mode unti= l then (CAKE in "bridged-ptm ether-vlan" mode)=0A2) I upgraded my router = from 3.16 (Devuan Jessie) to 4.9 (Devuan ASCII)=0A=0ASince then, no matte= r which setup I use, I cannot get CAKE to work as intended. Specifically,= any long-standing best effort stream (such as a remote rsync) will be th= rottled to a near grinding halt even though there is no other significant= traffic going on. Some random bursts can be seen (with iftop) but nothin= g ever gets close to half the maximum bandwidth. This is notably affectin= g the OpenWRT buildbots I'm hosting on this link.=0A=0AIn details:=0A=0A$= uname -a=0ALinux rapid-ts1 4.9.0-11-686 #1 SMP Debian 4.9.189-3+deb9u2 (= 2019-11-11) i686 GNU/Linux=0A=0ACake commit: 183b320 RFC 8622 diffserv3, = 4 & 8 LE PHB support=0A=0Acake setup on the wan iface: bandwidth 1Mbit di= ffserv3 dual-srchost nat nowash ack-filter split-gso bridged-vcmux no-sce= =0Athe available ATM uplink bandwith is 1.2Mbps, I tried going as low as = 700kbps, disabling ack-filter and setting "conservative" to see if it wou= ld make a difference, it wouldn't in any significant way: the upload woul= d still be severely throttled. I also tried disabling the ingress leg to = get that out of the equation: also no difference.=0A=0AAs I broke rule #1= of any setup upgrade (by changing both the link - VDSL to ADSL - and the= running kernel), I can't tell for sure where the fault lies; however I m= ust add something about the "native IPv6 DSLAM" bit:=0A=0AFree uses map-e= /map-t, i.e. ipip6 tunnels on its native v6 DSLAMs. The Freebox still off= ers a public IPv4 to the connected router, but inside the Freebox there i= s an ipip6 tunnel setup to encapsulate the IPv4 traffic into IPv6, a tunn= el over which I have no control. I wonder if this encapsulation and its a= ssociated overhead could be throwing CAKE computations off? FWIW, my rout= er now operates in dual-stack mode, with both a public IPv4 and a public = IPv6 (although for the time being my LAN remains IPv4 only).=0A=0AI haven= 't (yet) found a way to connect directly to the DSLAM without the Freebox= (using my VDSL modem as I did before), so I can't get around this partic= ular blackbox.=0A=0AI hope this provides enough detail, I'm happy to expa= nd as needed: I would really want my CAKE back :)=0A=0ACheers,=0AThibaut ----=_RainLoop_603_178428716.1576244609 Content-Type: text/html; charset="utf-8" Content-Transfer-Encoding: quoted-printable
H= i list,

I've been using CAKE on my DSL-connected Linux router for = the last few years, and it worked well until very recently. Two things ha= ppened:

1) My ISP (French "Free") switched my DSLAM to native IPv6= , which for the time being means that I had to revert to using their set-= top-box (Freebox) instead of the VDSL2 model I was using in bridge mode u= ntil then (CAKE in "bridged-ptm ether-vlan" mode)
2) I upgraded my rou= ter from 3.16 (Devuan Jessie) to 4.9 (Devuan ASCII)

Since then, no= matter which setup I use, I cannot get CAKE to work as intended. Specifi= cally, any long-standing best effort stream (such as a remote rsync) will= be throttled to a near grinding halt even though there is no other signi= ficant traffic going on. Some random bursts can be seen (with iftop) but = nothing ever gets close to half the maximum bandwidth. This is notably af= fecting the OpenWRT buildbots I'm hosting on this link.

In details= :

$ uname -a
Linux rapid-ts1 4.9.0-11-686 #1 SMP Debian 4.9.189= -3+deb9u2 (2019-11-11) i686 GNU/Linux

Cake = commit: 183b320 RFC 8622 diffserv3, 4 & 8 LE PHB support

cake setup on the wan iface: bandwidth 1Mbit diffserv3 = dual-srchost nat nowash ack-filter split-gso bridged-vcmux no-sce
the = available ATM uplink bandwith is 1.2Mbps, I tried going as low as 700kbps= , disabling ack-filter and setting "conservative" to see if it would make= a difference, it wouldn't in any significant way: the upload would still= be severely throttled. I also tried disabling the ingress leg to get tha= t out of the equation: also no difference.

As I broke rule #1 of a= ny setup upgrade (by changing both the link - VDSL to ADSL - and the runn= ing kernel), I can't tell for sure where the fault lies; however I must a= dd something about the "native IPv6 DSLAM" bit:

Free uses map-e/ma= p-t, i.e. ipip6 tunnels on its native v6 DSLAMs. The Freebox still offers= a public IPv4 to the connected router, but inside the Freebox there is a= n ipip6 tunnel setup to encapsulate the IPv4 traffic into IPv6, a tunnel = over which I have no control. I wonder if this encapsulation and its asso= ciated overhead could be throwing CAKE computations off? FWIW, my router = now operates in dual-stack mode, with both a public IPv4 and a public IPv= 6 (although for the time being my LAN remains IPv4 only).

I haven'= t (yet) found a way to connect directly to the DSLAM without the Freebox = (using my VDSL modem as I did before), so I can't get around this particu= lar blackbox.

I hope this provides enough detail, I'm happy to exp= and as needed: I would really want my CAKE back :)

Cheers,
Thib= aut
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