Re: [Bloat] ONTs and ITU - T G.988

[Marco Belmonte <marco@heavenlysanctuary.com>]

Well, I for one will be most interesting in watching your progress and 
am available if you need samples (500 Mb Fiber - Frontier FIOS).

Marco

On 1/12/2022 4:57 PM, Dave Taht wrote:
> What appeared to be the case was that a ONT had a 50ms buffer at
> 100Mbit and was reconfigured to drive a gig and thus only had 5ms.
>
> At least, that's what the data looked like. This was on a fairly
> recent reddit thread a month or two back, that I cannot find right
> now. I'm pretty sure it was in the context of eero's
> rolling out a working htb+fq_codel implementation finally for the eero
> 6, (or maybe it was the comcast AQM?0 and us discovering it didn't do
> any good, that the ont was seemingly brutally underbuffered, which
> took days of scratching my head.... multiple flent tests... wish I
> could find that thread...
>
> This is kind of ironic, but the structure of the speedtest (8+ flows
> with short RTTs) actually could lead naturally to buffers that short
> and few would notice.
>
> Anyway, that sparked me finally going and reading up a bit more about
> how ONTs work...
>
>
> On Wed, Jan 12, 2022 at 4:40 PM Marco Belmonte
> <marco@heavenlysanctuary.com> wrote:
>> Dave,
>>
>> Can you describe to me what under buffered would look like? Let's say
>> I'm playing Rocket League on a Frontier FIOS connection... When a
>> situation arises where the connection is under buffered you might see
>> __<Insert DT's Big Brain words here>___.
>>
>> A lot of interrupts being generated? connections timing out? lag?
>>
>> I'm guessing that many of the same symptoms that accompanying buffer
>> bloat also manifest themselves with buffer bleed?
>>
>> Marco
>>
>>
>> On 1/12/2022 3:42 PM, Dave Taht wrote:
>>> Up until this point I haven't cared all that much about fiber, as most
>>> of my observations were that it had "reasonable" buffering and all I
>>> could hold in my head was the 802.11 standards. Since cablemodems are
>>> well on their way to being fixed, wifi is looking good, and I recently
>>> came across an ONT that was actually underbuffered, my holiday reading
>>> consisted of pounding through a ton of fiber specs like this one:
>>>
>>> https://www.itu.int/rec/dologin_pub.asp?lang=e&id=T-REC-G.988-201711-I!!PDF-E&type=items
>>>
>>> There's a lot of promising info in this spec starting from page 104.
>>>
>>> My 1st question is - are there any ONTs that actually do do pause
>>> frames? Or providers that configure for them?
>>>
>>> My second is - what is a cheap way to setup a lab to emulate a good,
>>> common, version of gpon e2e?
>>>
>>> Third - what OS do these things run? Who makes a "good" one?
>>>
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