[tsvwg] Re: WGLC for A NQB PHB for Differentiated Services (draft-ietf-tsvwg-nqb) to end 27th May 2024.

[Sebastian Moeller <[e-mail]>]

Hi Jason,


> On 21. May 2024, at 15:57, Livingood, Jason <jason_livingood=[e-mail]> wrote:
> 
> On 5/21/24, 02:34, "Sebastian Moeller" wrote:
> 
>> [SM] Could you be a bit more explicit, what exactly did you test, what was posiztive and did yu also look for side effects?
> 
> While you directed this question to Michael, we have tested this as well in our field trials. We have for example, tested single queue with AQM and looked at p99 latency under load and jitter as well as median & max bitrate for different application flows - then turned on NQB LL and observed the same for the classic and LL queues. What we have found generally is that the bitrates, working latency, and jitter for classic traffic with single queue AQM and dual queue LL is the same; classic queue applications do not experience degradation.

[SM] Puzzled, how can the bitrate in the C-queue not change when there is also quantitative traffic in the L-queue?

> At the same time, the NQB flow experiences working latency that approaches idle latency, with consistently low latency.

[SM] Well, we know that priority scheduling does work and will give a sufficiently sparse traffic in the priority class shorter delays (and more potential throughput)... so that is not all that surprising.
Surprising is that according to your argument that improvement in service did not come at a cost for other traffic. And I question that, priority scheduling does not magically create more capacity or transmit opportunities, for every packet you treat to less delay, some other packet(s) will be treated to more delay. We can argue that the amount of this additional delay is insignificant, but that is a different claim than 'it does not exist' as you seem to be making above.


Regards
	Sebastian

> 
> JL
> 
>