From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: mail.toke.dk; spf=pass smtp.mailfrom=; dkim=fail; arc=none (Message is not ARC signed); dmarc=fail (Used From Domain Record) header.from=umbernetworks.com policy.dmarc=quarantine Received: from mail.umbernetworks.com (mail.umbernetworks.com [198.74.51.139]) by mail.toke.dk (Postfix) with ESMTPS id BE9841118C39; Wed, 20 May 2026 00:45:17 +0200 (CEST) Received: from webmail.umbernetworks.com (files.umbernetwork.com [198.74.51.139]) by mail.umbernetworks.com (Postfix) with ESMTPA id 1D90221A4A0; Tue, 19 May 2026 22:45:14 +0000 (UTC) MIME-Version: 1.0 Date: Tue, 19 May 2026 15:45:14 -0700 From: bob.mcmahon@umbernetworks.com To: David Lang Cc: "Livingood, Jason" , Frantisek Borsik , Cake List , Make-Wifi-fast , bloat , Jeremy Austin via Rpm , codel@lists.bufferbloat.net, "Dave.seddon Ca" , William Fisher , Igor Aleinikov , Jim , Jiml , Douglas Fairbairn , Thomas , Tim Odriscoll , Morten , Sebastian Moeller , Mt Denicolo , Mmcmahon01 , Santanu Sinha , Matthew , Koen DS , Shotaro Saito In-Reply-To: <0oq1n88q-36qn-p6s7-699s-p4nr0440p950@ynat.uz> References: <709dac7800ee7ad92aafd4eab1c761d9@umbernetworks.com> <0oq1n88q-36qn-p6s7-699s-p4nr0440p950@ynat.uz> Message-ID: X-Sender: bob.mcmahon@umbernetworks.com Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7bit X-MailFrom: bob.mcmahon@umbernetworks.com X-Mailman-Rule-Hits: nonmember-moderation X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; loop; banned-address; emergency; member-moderation Message-ID-Hash: I4UM7FYVFNX2KEE77JOBQLSDTJ4TT4JY X-Message-ID-Hash: I4UM7FYVFNX2KEE77JOBQLSDTJ4TT4JY X-Mailman-Approved-At: Wed, 20 May 2026 10:22:04 +0200 X-Mailman-Version: 3.3.10 Precedence: list Subject: [Make-wifi-fast] Re: [Bloat] Re: [Cake] "Fi-Wi is a new forwarding plane for wireless" - Bob McMahon List-Id: Lets make wifi fast again! Archived-At: List-Archive: List-Help: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: > the reason home wifi is so bad is because there is no coordination > between the wifi in the diffeent houses/apartments. you don't need to > tie all those devices into a single network to solve that, and unless > you do solve the coordination problem, there is no way for you to make > the rf environment better. > > coordination may only be an 80% solution compared to this, but 80% is a > lot. > David, Even granting the 80% claim, which I don't think holds across 134M occupied homes in the US once you measure broadly enough, the loss functions shift dramatically with density, workload, and metric. Throughput, tail latency, and jitter under load do not degrade for the same reasons, and they do not reduce to a single number. Even inside a single home with one AP and no neighbors, Wi-Fi exhibits pathologies unrelated to cross-network coordination: hidden queues, retry storms, aggregation bursts, EDCA backoff variance, roaming decisions made with stale information, and firmware behavior the operator cannot observe or control. ECN marking, L4S, pacing, and AQMs all assume the layer below them provides observable and reasonably bounded service time. Conventional APs do not provide that. Coordinating neighbors does not fix it. The deeper problem is architectural. Conventional Wi-Fi scatters the observations. No AP sees enough state to make globally correct decisions across space, time, and frequency, so every AP treats overlap as loss and reacts using local, partial information. Neighbor coordination cannot recover information that was never collected, nor can it impose deterministic service intervals on autonomous 802.11 MAC state machines running in opaque vendor firmware. Fi-Wi inverts that architecture. The 802.11 MAC moves to the concentrator, where the observations are co-located and scheduling decisions are made in software the operator or building owner controls. The radios handle PHY/RF execution. One RRH or twenty, the architectural property is the same: airtime scheduling, transport feedback, and observability exist in one place. I put together a small animation showing how contention probability rises rapidly even with relatively small contention windows and moderate active station counts. It helps visualize why systems often become MAC-limited before PHY-limited: https://www.umbernetworks.com/csma-preview.html The "single network" is ultimately a human management abstraction. RF, like rats, does not respect property boundaries. The medium is shared whether or not the management plane pretends otherwise. Coordination between autonomous networks tries to paper over a partition we invented, and the ceiling is set by the partition. Fi-Wi doesn't eliminate the partition globally. It dissolves it within a coverage area, by replacing autonomous APs with radio arrays serving one MAC. Inside the domain, there is no partition to paper over. Engineering that matches physics is the goal. Bob