Re: [tsvwg] tsw/ospa: Internet phone-in-QoS ?

[Sebastian Moeller <[e-mail]>]

Hi Jonathan,


> On Apr 14, 2020, at 22:44, Jonathan Morton <[e-mail]> wrote:
> 
>> On 14 Apr, 2020, at 10:46 pm, Toerless Eckert <[e-mail]> wrote:
>> 
>> I have been somewhat following how in the face of COVID-19,
>> the appropriate way to manage congestion control in the Internet 
>> seem to be heads of countries reaching out to the one large content provider
>> they know (Netflix) and ask him to reduce bandwidth pressure on the
>> Internet. Of course, heads of states with differently aged children
>> would know that Disney+ or Apple might be other relevant streaming
>> providers to reach out to, but alas, we have forgotten to elect 
>> those heads of states on such key criteria.
>> 
>> That was of course tongue in cheek of course, but i was somewhat surprised
>> that nobody took up the opportunity so far to ask something like "how are we
>> doing on Net Neutrality" ?, or "what the heck would we actually want it to be" ?
>> 
>> I can see a lot of operational short term workarounds to
>> approximate solutions less silly than phoning CEOs of random companies,
>> but it really strikes me as highly strange that events like the
>> ones we're in right now should not have us re-think to what extend
>> our current presumed strategy is sufficient…
> 
> I'm pretty sure that if ISPs implemented congestion control measures correctly at layer 3, there would be no need to take traffic-source-specific actions so high up the stack (beyond the machine layers) to merely ensure that backhaul networks and peering arrangements are not flooded into oblivion.  I'm talking about simple, well-understood measures such as:

	I disagree a bit, we are witnessing a policy decision by the EU that assumed purely recreational streaming traffic shall take a back-seat to assumed work related "home-office" traffic IFF the network experiences congestion. This is as much about how to distribute available bandwidth between different traffic "classes" as it is about avoiding the undesirable side-effects of congestion, just dealing with the second is not sufficient to solve the first.


> 
> 1: Implement AQM at every potential bottleneck, to limit effect of excess traffic on latency & reliability.  In this context, even WRED without ECN is better than nothing, but doing better would be nice.

	+1

> 
> 2: Share bottleneck capacity fairly between subscribers, so that one household's heavy traffic doesn't unduly impact the service to other households.  Want to download three Steam games, five Netflix streams and a 500-peer BitTorrent swarm all at once?  Go right ahead, but your next-door neighbour will get just as much bandwidth for his videoconference call about keeping a factory production line going.

	+1; and not because equal sharing is optimal in any sense, but because it is the best an intermediate hop can do with its limited information (and even there people complain that per-something queueing is too expensive computationally to do at scale in high speed gear)...
	in a sense fair sharing is the "democracy" of schedulers with Winston Churchill's citation (gently ammended) applicable:
"No one pretends that democracy/FQ is perfect or all-wise. Indeed it has been said that democracy/FQ is the worst form of Government/scheduling except for all those other forms that have been tried from time to time.…"


> 
> If those two measures were widely implemented, there would be no need for data caps, and streaming services' existing quality adjustment algorithms would automatically adjust to match available capacity.

	It is argued, that most streamers use adaptive streaming already, so in essence will scale back under load (but that does not work as well as it should, and due to the existence of over-sized and under-managed queues in the internet creates transient latency excursions that make interactive traffic types like vide-conferencing and gaming suffer).

> 
> There are already published RFCs detailing all the necessary technology to make this work.  It's already available in many end-hosts and CPE boxes.  It's just not widely deployed and switched on in ISPs' networks, where it can do the most good.  But there *are* a few ISPs who have done it, and thus might be good sources of practical expertise on the subject, if only the industry at large was willing to listen.

	+1; but again that is mainly orthogonal to the EU/BEREC action that ruffled a few feathers in the tech community, no?

Best Regards
	Sebastian


> 
> - Jonathan Morton