[Cake] Re: [Rpm] Re: [Bloat] Re: "Fi-Wi is a new forwarding plane for wireless" - Bob McMahon

[Frantisek Borsik <frantisek.borsik@gmail.com>]

Hey Bob,

This is all nice and all, but it really doesn't matter. The only measurable
term IMO we really need is this - is the setup we are using good enough and
delivering all we need? And the answer for ISP like Dan and many that will
come "to Jesus" is sounding YES. It's here, it's cheap, it's getting better.

You will get your evidence and then what? When (and big iF) Fi-Wi will
materialize, we will have Wi-Fi 8
<https://www.linkedin.com/feed/update/urn:li:activity:7460998580456116224/>
for those interested in chasing marginal improvements and the latest thing.
Jonathan Morton will deliver his improvement on CAKE, we might even get
into microsecond territory. There will be FQ-PIE, PURPLE CAKE, HTB-MQ (to
supplement CAKE-MQ)...

Anyway, you will like this:
https://arstechnica.com/gadgets/2017/02/going-hands-on-and-behind-the-scenes-at-the-plume-wi-fi-hq/

Plume used to do this, you will have your Fi-Wi house test bed up and
running, soon. Let's have fun and do another round of the good ole
Wi-Fi/mesh router rumble:

https://arstechnica.com/gadgets/2016/09/the-router-rumble-ars-diy-build-faces-better-tests-tougher-competition/
https://arstechnica.com/gadgets/2016/12/review-comparing-google-wifi-to-other-mesh-networking-heavyweights/

Maybe Jim and Ars Technica would be interested in it.


All the best,

Frank

Frantisek (Frank) Borsik


*In loving memory of Dave Täht: *1965-2025

https://libreqos.io/2025/04/01/in-loving-memory-of-dave/


https://www.linkedin.com/in/frantisekborsik

Signal, Telegram, WhatsApp: +421919416714

iMessage, mobile: +420775230885

Skype: casioa5302ca

frantisek.borsik@gmail.com


On Sun, May 24, 2026 at 11:57 PM <bob.mcmahon@umbernetworks.com> wrote:

> Hi Frank,
>
> The question needs to be framed in measurable terms.
>
> The systems you named operate at different layers than the 802.11 MAC/PHY
> layer where TXOP allocation, retries, EDCA contention, AMPDU behavior, and
> airtime utilization occur throughout the building. batman-adv routes
> between mesh nodes. CAKE and FQ-CoDel operate on IP-layer queues. QoE
> middle-boxes operate from the WAN/IP side.
>
> So the question is whether IP-layer AQMs or WAN-side QoE systems affect
> measurable 802.11 MAC/PHY behavior under load.
>
> If they do, the predicted MAC/PHY effects would include:
>
>    - lower failed TXOP percentage
>    - lower retransmission airtime fraction
>    - improved AMPDU completion efficiency
>    - higher payload delivered per TXOP
>    - lower AMPDU truncation frequency
>    - reduced EDCA wait distributions
>    - improved airtime utilization
>    - reduced service-time variance
>    - changed MCS distributions across stations under realistic spatial
>    topology, particularly at coverage edges and where multiple APs or RRHs are
>    candidates for node selection
>
> That is the measurement gap I am pointing at. The industry has extensive
> 802.11 feature lists and marketing claims, with comparatively little open
> tooling to falsify what those actually do to building wide 802.11 MAC/PHY
> behavior under real multi-client, multi-AP load.
>
> I developed and still maintain iperf2 because throughput alone has proven
> an insufficient measurement model for network behavior, e.g. latencies and
> responsiveness under load. Features added to iperf2 include:
>
>    - trip-times
>    - bounceback testing
>    - one-way IP packet timing measurements
>    - packet-level latency histograms
>    - message-level (TCP write/read completion) latency histograms
>    - responsiveness under load measurements
>    - enhanced per-interval reporting
>    - CWND reporting
>    - RTT reporting
>    - bytes/packets in-flight reporting
>    - TCP retransmission reporting
>    - TCP congestion-control selection (CUBIC, BBR, Prague, etc.)
>    - udp-l4s including CE counters and durations
>    - isochronous traffic generation
>    - socket-layer pacing via SO_MAX_PACING_RATE
>    - token-bucket write-rate control
>    - Markov-chain packet-size generation
>    - UDP latency/jitter analysis
>    - multicast testing
>
> Those measurements operate above the 802.11 MAC/PHY. The missing layer
> remains open 802.11 MAC/PHY telemetry, which is what I'm building now.
>
> This measurement standard should apply equally to any claim from any
> architecture, including Fi-Wi.
>
> The question becomes: does centralized MAC telemetry and coordinated
> airtime control affect measurable 802.11 MAC/PHY behavior under load
> relative to autonomous AP operation?
>
> Measure the same MAC/PHY metrics under equivalent topology, offered load,
> and client mix. If those measurements do not improve relative to baseline,
> the architectural claim of Fi-Wi fails. We won't know until Fi-Wi is
> designed, built, deployed and measured at many different locations. The
> theoretical case is strong.  Centralized scheduling, joint optimization,
> and observability all argue for it. The design and measurements are the
> next steps. Then we'll see based on evidence.
>
> Bob
>
> Technically, Betamax was superior to VHS, and yet...
>
> If we would be talking about FiWi pre-jump from Wi-Fi 5 to Wi-Fi6/E/7, I
> would even try to do my best and ignore https://fastgood.cheap.
> But we are not there, for better or for worse.
>
> ISPs like Dan that use Wi-Fi 6 (with mesh, especially based on batman-adv
> and FQ-CoDel / CAKE) and above at customer premises and Quality of
> Experience middle-box on their last-mile, while providing good, personal
> customer service (not some crappy outsourcing of it to India or "AI") will
> be hard to beat, even for a big telco/ISP offering cheaper price. Yes, some
> people will leave but the most of them will be coming back.
>
> This is, believe it or not, not a high bar to jump over, even though not
> many ISPs are getting it already. We all know that more or less: "Bandwidth
> is a lie, Bandwidth is dead," so it's coming. They will be throwing more
> bandwidth on it for some time, but we will be getting from "innovators" to
> "early adopters" soon and then, all we need is just that "crossing the
> chasm."
>
> Despite all the difficulties, it will be faster and cheaper - also "good
> enough," than FiWi. Or rather, it's here already, it's just not evenly
> distributed.
> There might be some good niche use case for FiWi, though, once it will
> mature and get there.
>
> All the best,
>
>
> Frank
>
>
>
> Frantisek (Frank) Borsik
>
>
>
> *In loving memory of Dave Täht: *1965-2025
>
> https://libreqos.io/2025/04/01/in-loving-memory-of-dave/
>
>
>
> https://www.linkedin.com/in/frantisekborsik
>
> Signal, Telegram, WhatsApp: +421919416714
>
> iMessage, mobile: +420775230885
>
> Skype: casioa5302ca
>
> frantisek.borsik@gmail.com
>
> On Sun, May 24, 2026 at 2:12 AM dan <dandenson@gmail.com> wrote:
>
>
>
> On Sat, May 23, 2026 at 10:36 AM <bob.mcmahon@umbernetworks.com> wrote:
>
> > I don't have arguments on the technical bits of your reply.
>
> The industry hasn't provided open source tools to analyze 802.11 properly.
> The proprietary ones are tightly coupled to chip firmware, owned by 802.11
> vendors, and not for sale.
>
> You've built solid networks, especially given how little 802.11 MAC-layer
> and MCS observability current tooling exposes. I hope to make open source
> 802.11 MAC telemetry tools available sooner rather than later. These will
> run on both an ESP32-C5 and an RPi5. The inexpensive ESP32 allows monitors
> to be placed throughout a venue at low cost.
>
> A key issue is what's being measured. Your deployment data is a capacity
> analysis. Once baseline capacity is adequate, user experience is driven by
> tail latency and service-time variance rather than throughput. A network
> can saturate aggregate throughput while still showing large service-time
> variance and long per-flow tails under contention. These are different
> measurements.
>
> And CODEL and CAKE are IP-layer mechanisms. They don't operate on 802.11
> TXOPs or airtime sojourn, which is where the contention and service-time
> variance actually live. AQL is closer. It operates on airtime at the
> driver/firmware boundary, but it's still per-AP. There's no coordination
> across APs and no MAC telemetry exposed upward.
>
> Slide 6 of my DPDK Summit Stockholm talk lays out the layering:
> https://www.umbernetworks.com/DPDK_WiFi_Stockholm_Pres.html
>
> Check out iperf2's advanced features around --bounceback, --trip-times,
> and --histograms. These are available as open source. Man page:
> https://iperf2.sourceforge.io/iperf-manpage.html
>
> I'll try to respond with some metrics soon. My rig is down at the moment,
> so give me a few days.
>
> Bob
>
>
> I agree.  However, I'm not actually just measuring throughput, but running
> latency sensitive applications without issues.  Frank might attest to my
> efforts to reduce latency and I routinely share data on lqos (and another
> QoE product's) TCP measurements for latency and among QoE users, I believe
> my network is top 1% in latency and jitter and in the WISP space.
> Obviously I'm not going to compete with XGSPON operators.. (though I'm only
> measuring TCP because that's the 'easiest' to measure passively
> practically).  While this is not an engineering adequate benchmark, if my
> VoIP handsets work over wireless then the wireless is good is a very
> reasonable latency, jitter, loss argument.  And I run a few brands of WiFi
> based VoIP phones (Fanvill Wxxx series, Yealink Wxx and AXxx series).
> Similarly, if the sonos works and is in sync, the wifi is good.
>
> As a service company and as a user, I don't really care so much where the
> goodness is in the system, mac layer or IP having cake work it's magic.
> Basically running an AP on OFMDA (as much as possible) and well under the
> 'red line' capacity delivers great results on WiFi7 radios (and some WiFi6
> radios).  I have no doubt that FiWi could get more of the theoretical
> throughput delivered at the mac layer.
>
> Deliverables are all that matter to me and I think to buyers and users.
> Benchmarks test deliverables which is great and I'm a routing iperf* user.
> It's engineering's problem to develop the next tech *AND* solicit funding
> to do so.
>
>
>