[Bloat] [Cerowrt-devel] DOCSIS 3+ recommendation?

MUSCARIELLO Luca IMT/OLN luca.muscariello at orange.com
Fri Mar 20 04:18:35 EDT 2015

I agree. Having that ping included in Ookla would help a lot more


On 03/20/2015 12:18 AM, Greg White wrote:
> Netalyzr is great for network geeks, hardly consumer-friendly, and even so
> the "network buffer measurements" part is buried in 150 other statistics.
> Why couldn't Ookla* add a simultaneous "ping" test to their throughput
> test?  When was the last time someone leaned on them?
> *I realize not everyone likes the Ookla tool, but it is popular and about
> as "sexy" as you are going to get with a network performance tool.
> -Greg
> On 3/19/15, 2:29 PM, "dpreed at reed.com" <dpreed at reed.com> wrote:
>> I do think engineers operating networks get it, and that Comcast's
>> engineers really get it, as I clarified in my followup note.
>> The issue is indeed prioritization of investment, engineering resources
>> and management attention. The teams at Comcast in the engineering side
>> have been the leaders in "bufferbloat minimizing" work, and I think they
>> should get more recognition for that.
>> I disagree a little bit about not having a test that shows the issue, and
>> the value the test would have in demonstrating the issue to users.
>> Netalyzer has been doing an amazing job on this since before the
>> bufferbloat term was invented. Every time I've talked about this issue
>> I've suggested running Netalyzer, so I have a personal set of comments
> >from people all over the world who run Netalyzer on their home networks,
>> on hotel networks, etc.
>> When I have brought up these measurements from Netalyzr (which are not
>> aimed at showing the problem as users experience) I observe an
>> interesting reaction from many industry insiders:  the results are not
>> "sexy enough for stupid users" and also "no one will care".
>> I think the reaction characterizes the problem correctly - but the second
>> part is the most serious objection.  People don't need a measurement
>> tool, they need to know that this is why their home network sucks
>> sometimes.
>> On Thursday, March 19, 2015 3:58pm, "Livingood, Jason"
>> <Jason_Livingood at cable.comcast.com> said:
>>> On 3/19/15, 1:11 PM, "Dave Taht" <dave.taht at gmail.com> wrote:
>>>> On Thu, Mar 19, 2015 at 6:53 AM,  <dpreed at reed.com> wrote:
>>>>> How many years has it been since Comcast said they were going to fix
>>>>> bufferbloat in their network within a year?
>>> I¹m not sure anyone ever said it¹d take a year. If someone did (even if
>>> it
>>> was me) then it was in the days when the problem appeared less
>>> complicated
>>> than it is and I apologize for that. Let¹s face it - the problem is
>>> complex and the software that has to be fixed is everywhere. As I said
>>> about IPv6: if it were easy, it¹d be done by now. ;-)
>>>>> It's almost as if the cable companies don't want OTT video or
>>>>> simultaneous FTP and interactive gaming to work. Of course not. They'd
>>>>> never do that.
>>> Sorry, but that seems a bit unfair. It flies in the face of what we have
>>> done and are doing. We¹ve underwritten some of Dave¹s work, we got
>>> CableLabs to underwrite AQM work, and I personally pushed like heck to
>>> get
>>> AQM built into the default D3.1 spec (had CTO-level awareness & support,
>>> and was due to Greg White¹s work at CableLabs). We are starting to field
>>> test D3.1 gear now, by the way. We made some bad bets too, such as
>>> trying
>>> to underwrite an OpenWRT-related program with ISC, but not every tactic
>>> will always be a winner.
>>> As for existing D3.0 gear, it¹s not for lack of trying. Has any DOCSIS
>>> network of any scale in the world solved it? If so, I have something to
>>> use to learn from and apply here at Comcast - and I¹d **love** an
>>> introduction to someone who has so I can get this info.
>>> But usually there are rational explanations for why something is still
>>> not
>>> done. One of them is that the at-scale operational issues are more
>>> complicated that some people realize. And there is always a case of
>>> prioritization - meaning things like running out of IPv4 addresses and
>>> not
>>> having service trump more subtle things like buffer bloat (and the
>>> effort
>>> to get vendors to support v6 has been tremendous).
>>>> I do understand there are strong forces against us, especially in the
>>>> USA.
>>> I¹m not sure there are any forces against this issue. It¹s more a
>>> question
>>> of awareness - it is not apparent it is more urgent than other work in
>>> everyone¹s backlog. For example, the number of ISP customers even aware
>>> of
>>> buffer bloat is probably 0.001%; if customers aren¹t asking for it, the
>>> product managers have a tough time arguing to prioritize buffer bloat
>>> work
>>> over new feature X or Y.
>>> One suggestion I have made to increase awareness is that there be a
>>> nice,
>>> web-based, consumer-friendly latency under load / bloat test that you
>>> could get people to run as they do speed tests today. (If someone thinks
>>> they can actually deliver this, I will try to fund it - ping me
>>> off-list.)
>>> I also think a better job can be done explaining buffer bloat - it¹s
>>> hard
>>> to make an Œelevator pitch¹ about it.
>>> It reminds me a bit of IPv6 several years ago. Rather than saying in
>>> essence Œyou operators are dummies¹ for not already fixing this, maybe
>>> assume the engineers all Œget it¹ and what to do it. Because we really
>>> do
>>> get it and want to do something about it. Then ask those operators what
>>> they need to convince their leadership and their suppliers and product
>>> managers and whomever else that it needs to be resourced more
>>> effectively
>>> (see above for example).
>>> We¹re at least part of the way there in DOCSIS networks. It is in D3.1
>>> by
>>> default, and we¹re starting trials now. And probably within 18-24 months
>>> we won¹t buy any DOCSIS CPE that is not 3.1.
>>> The question for me is how and when to address it in DOCSIS 3.0.
>>> - Jason

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