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[37.219.197.32]) by smtp.gmail.com with ESMTPSA id 2adb3069b0e04-58871d48262sm1001907e87.53.2025.09.29.22.19.01 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Mon, 29 Sep 2025 22:19:03 -0700 (PDT) Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 (Mac OS X Mail 14.0 \(3654.100.0.2.22\)) From: Jonathan Morton In-Reply-To: Date: Tue, 30 Sep 2025 08:18:59 +0300 Cc: David Lang , m@jaap.pro, "cake@lists.bufferbloat.net" , Frantisek Borsik Content-Transfer-Encoding: quoted-printable Message-Id: <962896BA-6EE5-4815-B6F9-AC50B7252642@gmail.com> References: <2064666241.42029.1759061544846@app.mailbox.org> To: dave seddon X-Mailer: Apple Mail (2.3654.100.0.2.22) Message-ID-Hash: ORDHNF5ALXONA4EG3H4JZBZB46HNEB65 X-Message-ID-Hash: ORDHNF5ALXONA4EG3H4JZBZB46HNEB65 X-MailFrom: chromatix99@gmail.com X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; loop; banned-address; emergency; member-moderation; nonmember-moderation; administrivia; implicit-dest; max-recipients; max-size; news-moderation; no-subject; digests; suspicious-header X-Mailman-Version: 3.3.10 Precedence: list Subject: [Cake] Re: help request for cake on a large network List-Id: Cake - FQ_codel the next generation Archived-At: List-Archive: List-Help: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: > On 28 Sep, 2025, at 8:07 pm, dave seddon = wrote: >=20 > cakeConfig =3D { > Bandwidth =3D "990M"; # We currently have 1Gb/s, so this is our = limit > OverheadBytes =3D 38; # Ethernet overhead (preamble + inter-frame = gap + FCS) > MPUBytes =3D 84; # Minimum packet unit for Ethernet > NAT =3D true; > FlowIsolationMode =3D "triple"; > PriorityQueueingPreset =3D "besteffort"; > }; It's perhaps worth talking about these parameters a bit. You probably realise that the overhead compensation should be set up for = the physical bottleneck link. Not everything is, or behaves exactly = like, an Ethernet cable, even if the connection between your router and = the transceiver for that link physically is one. Or it might really be = Ethernet, but with extra headers patched into each Ethernet frame (in a = domestic context, that's what PPPoE partially is, but VLANs add an extra = couple of words to a frame too). If in doubt, err on the side of = assuming there's more overhead than you know about. These parameters = are, however, completely inadequate to describe wireless links, = especially WiFi. I'd also like to remind everyone what "triple" flow isolation is. It's = a way to get something like host-and-flow isolation when you're not = certain which side of the link the hosts that want isolating from each = other are; there's a heuristic which effectively decides, dynamically = for each flow, whether to treat it as being src-host or dst-host = isolated. I put it in mainly to serve as a sensible default, since = blindly choosing one or the other would get it wrong exactly half the = time. I don't really like seeing it in a config file that someone's = actually worked on. It's better to explicitly configure this rather than using the = heuristic. The tc-cake keywords are "dual-srchost" if the hosts to be = isolated are upstream of Cake, and "dual-dsthost" if they are = downstream. In a typical installation where two instances of Cake are = managing both directions of traffic, one will be configured each way. It's also possible to disable host-isolation entirely, using the "flows" = keyword to provide the same kind of flow-isolation as fq_codel (or most = other forms of FQ) does. Cake can also provide only host isolation, = relying entirely on statistical multiplexing (and the beneficience of = AQM) for managing flows to each host; the keywords are then "srchost" = and "dsthost" with the same meaning as above. If you are seriously = worried about the number of active users at critical moments, this could = be a useful option for you; the number of hosts Cake can fully handle in = this mode is the same as the number of flows it can handle in the normal = flow-isolation modes. - Jonathan Morton=