From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-io1-xd33.google.com (mail-io1-xd33.google.com [IPv6:2607:f8b0:4864:20::d33]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by lists.bufferbloat.net (Postfix) with ESMTPS id B05E83B29D for ; Mon, 29 Nov 2021 07:02:43 -0500 (EST) Received: by mail-io1-xd33.google.com with SMTP id e144so21014345iof.3 for ; Mon, 29 Nov 2021 04:02:43 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc:content-transfer-encoding; bh=/CVdO3cJOPwl4kS5cVNE+4e7hXOTw0VDOxJbaAu/WBk=; b=ELFNbMStwdv6aJ1twwvMbIZLEB91zHPA6GWVw1Z+AeQI2cgKk4w7dwS/Hu3Rxt2bLL oIXK9j7SxuUMORagtBNWzZk57LubdcSdF5WwElhecmbI+CZTHmvvWdrcKMT3DUmxx7fG YB2XTnDz4gmVJZyjaaR0q/2JA7jQ9hLKvI2yqZ3zKYIWVrdK0lB3DE+rPW/ZOI5LrOvL NaRiZsX1nv/d+ttCJZf8J3nbTJtTERNY1rs2M8eaYoDqYMr+vJqU8heaAOtGk8T3KmIH qBDII1oNdgJamUxDUcSVeKfIbzz/Yoss/B7PJ0+EyBohFox9+QDn3CveBy5GPwhUeBLF vFwQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc:content-transfer-encoding; bh=/CVdO3cJOPwl4kS5cVNE+4e7hXOTw0VDOxJbaAu/WBk=; b=FA11t/+uJFyxDfD6RFtMrl66c69Fr0Nicm0YHAjQZ7LXZ+r8RPoip9VGykAiCfrvw4 bHDzKqMiJNKhU10WF5BC8X2QiAB8WdQPlOo8bBxOwY+pcxIi6I6GNIFoXnfMcK8ZUswV oY5JtCs2YlTxA2gLeT29LctxwaVetk9U2tBzxARIhuTrLm5m557ri/Xsp9upBL9n59oS Z+D/j5jn9+9PWz7y6EYwrp0t1XzRbYHAZ8+6Yz+kejs2XRIp0ZSb/6R4jYxoikLqkClG GTwrFvAG6erW3EcuvwxXqqnNGB6nTC7rxMKQytDtc7nA78uFgJqD/BcAweIlj0xRrLZG e2zA== X-Gm-Message-State: AOAM533SiaLDc88YPOQpW7ZRxz4HLcC99baSxPoBmQD3j8thDDHTpkjT TEyeJRZgFA8HlYXG55qcBZm8xgu7gMbuKYUttIc= X-Google-Smtp-Source: ABdhPJzMLPUupuWFdvEH+9qpyQvJTw8e1Brfqxh+Fta/i7LiCXLvTp9+S7ivjFQ36ojEW6RrAPoi3JYzEwNWdI6NYfo= X-Received: by 2002:a05:6638:160c:: with SMTP id x12mr64860337jas.60.1638187362102; Mon, 29 Nov 2021 04:02:42 -0800 (PST) MIME-Version: 1.0 References: In-Reply-To: From: Dave Taht Date: Mon, 29 Nov 2021 04:02:30 -0800 Message-ID: To: Mikel Irazabal Bengoa Cc: bloat , Navid Nikaein , Elena Lopez Aguilera , Ilker Demirkol , Robert Schmidt , irazabal@eurecom.fr Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Subject: Re: [Bloat] Preventing RLC Buffer Sojourn Delays in 5G X-BeenThere: bloat@lists.bufferbloat.net X-Mailman-Version: 2.1.20 Precedence: list List-Id: General list for discussing Bufferbloat List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 29 Nov 2021 12:02:43 -0000 On Mon, Nov 29, 2021 at 2:28 AM Mikel Irazabal Bengoa wrote: > > Hi Dave, > > It is nice to see that this journal caught your attention. Answers betwee= n the lines Good paper! I try to catch up on the backlog of bufferbloat related publications on sundays. Lately, the backlog has got out of hand. > I am always puzzled as to why folk don't benchmark fq-codel (or > something like BQL) > One solution that we propose, DRQL (Dynamic RLC Queue Limit) is pretty mu= ch inspired by BQL, as the name suggests. So yes, one could say that we imp= lemented BQL for RAN. > Maybe this article also answers some questions > https://ieeexplore.ieee.org/document/9169837 Thx! > Regarding fq-codel, we implemented codel, which for our scenario was suff= icient as they were arriving two different QFI type of flows. (one could th= ink of QFIs as DiffServ as there are also exists 64 QoS defined by 3GPP TS= 23.501) Wading through the maze of these standards here is always hard and thank you for referencing the correct document and translating back into language I sort of understand. But in the internet, voice and video are not diffserved, pretty much everything is best effort. > If you want to implement fq-codel on the RLC DRBs, you have to slightly c= ontradict the 3GPP standard. DRBs are initiated by the UEs and, I believe, = that you cannot have packets with the same QFI in different DRBs. > If, on the other hand, you want to implement them in the upper sublayers = (e.g., above SDAP) you need to go beyond the 3GPP specification. It used to be when standards met an actual implementation issue, that the implementation lept forward with something that worked, the vendor kept the idea proprietary for several years, and then, maybe, maybe, it made it into a future revision of the spec. > In any case, among other things, we are currently working at Eurecom in a= flexible traffic flow control mechanism for at least, OpenAirInterface's R= AN stack, to enable more people test their algorithms in a real 5G RAN test= bed. I am delighted to hear of this effort. How do we get in on it? > in scenarios like these. Are the headers not available in the RAN? > (forgive me for forgetting) > > They are available until the PDCP sublayer, AFAIR. > > Anyway, their "vanilla" scenario shows 5G with > 1sec of buffering. > Is that real? > > It is real in the OpenAirInterface project. > https://gitlab.eurecom.fr/oai/openairinterface5g That steer especially. I do much better reading code than specs. > This does not prove that is real or false in commercial base stations. But it is a starting point. One of the cooler things we've been doing with irtt btw is using it at a very high (3ms) interval to map networks like starlinks. I'd really like to start up a project to look harder at lte/5g this way. > Additionally, even though the queuing structure does not change, keep in = mind that the experiments where conducted with a 3GPP compliant 4G RAN stac= k and some additional code for the described scenario. > > BR, > Mikel > > > On Mon, 29 Nov 2021 at 01:34, Dave Taht wrote: >> >> A nice comparison of BBR vs Codel vs FIFO vs their cross-layer >> solution. (they used irtt!) >> >> I am always puzzled as to why folk don't benchmark fq-codel (or >> something like BQL) >> in scenarios like these. Are the headers not available in the RAN? >> (forgive me for forgetting) >> >> Anyway, their "vanilla" scenario shows 5G with > 1sec of buffering. >> Is that real? >> >> https://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=3D9369375 >> >> -- >> I tried to build a better future, a few times: >> https://wayforward.archive.org/?site=3Dhttps%3A%2F%2Fwww.icei.org >> >> Dave T=C3=A4ht CEO, TekLibre, LLC --=20 I tried to build a better future, a few times: https://wayforward.archive.org/?site=3Dhttps%3A%2F%2Fwww.icei.org Dave T=C3=A4ht CEO, TekLibre, LLC