[Bloat] number of home routers with ingress AQM

[Jonathan Foulkes]

Responses below

> On Apr 2, 2019, at 8:10 AM, Mikael Abrahamsson <swmike at swm.pp.se> wrote:
> 
> On Tue, 2 Apr 2019, Sebastian Moeller wrote:
> 
>> I just wondered if anybody has any reasonable estimate how many end-users actually employ fair-queueing AQMs with active ECN-marking for ingress traffic @home? I am trying to understand whether L4S approach to simply declare these as insignificant in number is justifiable?
> 
> If more than 0.01% of HGWs did this I'd be extremely surprised.

My observation is that the number is very small, even devices with SQM services, rarely see them enabled, and when they are, are set to sub-optimal values. 
I see Sebastian doing a valiant, even heroic effort at addressing technical users questions on forums, but even those users seem confused at times.

> 
>> I know in openwrt with sqm that is the default, but I have no idea about
> 
> To configure ingress shaping you actually have to know the speed and configure it. It's not the default. Also, it's useless if the transport network queues the packets at lower rate than at what you receive it. When I used my DOCSIS connection it routinely forwarded packets at lower rates than what I bought (and had configured the ingress shaper for).

As noted in other responses, the actual throughput needs to be measured and then monitored to ensure the ingress shaping is aligned with current capacity of the link. And not just the HGW to BNG, but just as importantly, account for any constraints in backhaul from the BNG.

> 
>> the number of devices that actually use sqm in the field; @Jonathan: does evenroute have numbers you are willing to share, like total numbers or % of iqrouters with ecn-marking ingress routing active?

@Sebastian, 100% of IQrouters running firmware 3.x (which uses Cake as the default AQM) respect/use ECN. This has been shipping since September, 2018. All existing v2 IQrouters (first ship January 2017) may upgrade to 3x (user initiated, but one-click).
As for split, 70% of deployed IQrouters are doing ECN today. As for count, well, that’s private. But the good new is we have ISP customers rolling them out at a good clip. 
Turns out that having a sane traffic manager at the HGW on every node of a DSLAM is very good for the DSLAM, the backhaul and the actual users, who quit screaming at the ISP ;-)

> 
> ISP networks typically looks like this in the ISP->HGW direction:
> 
> BNG->L2->L2->HGW
> 
> This is the same regardless if it's DSL, DOCSIS, FTTH/PON or whatever. So shaping is done egress on BNG and it tries to send at lower rate than any of the L2 devices. Generally there is no ingress shaping of any kind on the HGW, it doesn't even know what speed the subscription is.
> 
> -- 
> Mikael Abrahamsson    email: swmike at swm.pp.se
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