Re: [Detnet] TSN scheduling/queuing algorithms and DetNet

["Black, David" <[e-mail]>]

Hi Florian,

Still posting as an individual - the two of us are on the same page ...

> Since I was not able to attend the meeting and I can not find any minutes or recording, I would love to get more background about this question, especially why you explicitly marked **algorithms** as bold.

I was drawing a distinction between the entire scope of TSN technology, which is a layer-2 subnet when fully deployed, versus just the TSN scheduling/queuing algorithms (e.g., Qbv) which are readily deployable at layer 3.

> And for those scenarios my current working assumption is actually that all DetNet nodes that route on L3 between L2 TSN
> networks would be able to directly apply all TSN techniques (like Qbv and CQF) without any special consideration for them on L3.

+1 on "directly apply all TSN techniques (like Qbv and CQF) without any special consideration for them on L3" - and in particular, I believe that this direct application is possible now (i.e., no need to wait for IETF to publish a detnet RFC that says it's ok to do this obvious thing ...).

> The only exception is that the L3 processing MIGHT take more time than L2 bridging and this might have to be taken into account e.g. when calculating a Qbv schedule.
> Do you agree or is there something I overlook?

I don't think you've missed anything major ...

Thanks, --David

-----Original Message-----
From: Florian Kauer <[e-mail]> 
Sent: Thursday, October 5, 2023 3:22 AM
To: Black, David; [e-mail]
Cc: Black, David
Subject: Re: [Detnet] TSN scheduling/queuing algorithms and DetNet


[EXTERNAL EMAIL] 

Hi David,
thanks for bringing up this point!
Since I was not able to attend the meeting and I can not find any minutes or recording, I would love to get more background about this question, especially why you explicitly marked **algorithms** as bold.

For the use cases I am currently considering for DetNet (industrial control/vPLC and pro audio) the scaling requirements (time asynchrony, propagation latency...) are IMHO of lower importance at the moment. And for those scenarios my current working assumption is actually that all DetNet nodes that route on L3 between L2 TSN networks would be able to directly apply all TSN techniques (like Qbv and CQF) without any special consideration for them on L3. The only exception is that the L3 processing MIGHT take more time than L2 bridging and this might have to be taken into account e.g. when calculating a Qbv schedule. Do you agree or is there something I overlook?

Thanks,
Florian

On 04.10.23 23:30, Black, David wrote:
> For clarity, this is posted as an individual contributor …
> 
>  
> 
> In the most recent open working meeting, Toerless and I had a discussion about whether DetNet nodes could use the TSN scheduling/queuing algorithms.
> 
>  
> 
> Checking the DetNet RFCs, what I believe I see is:
> 
>   * Toerless’s assertion that all DetNet RFC references to TSN refer to layer-2 TSN subnets appears to be correct.
>   * OTOH, I did not see anything that prohibits implementation and use of the TSN scheduling/queuing **algorithms** at layer 3 in DetNet nodes.
> 
>  
> 
> I would hope that it’s not necessary to publish an RFC to bless the use of the TSN scheduling/queuing algorithms at layer 3 in DetNet Nodes …
> 
>  
> 
> Thanks, --David
> 
> * *
> 
> *David L. Black, *Sr. Distinguished Engineer, Technology & Standards
> 
> Infrastructure Solutions Group,*Dell Technologies*
> 
> mobile [phone] [e-mail] <mailto:[e-mail]>
> 
>  
> 
> 
> _______________________________________________
> detnet mailing list
> [e-mail]
> https://urldefense.com/v3/__https://www.ietf.org/mailman/listinfo/detnet__;!!LpKI!nabqKqkaJqASqxUmFFXsdWshrCNzaQHg7m-v-hGX_vjxDkaPwEjaN_7LLu4bVsAoreoYzg2j8oO_zNFgpKpK_IqND_rO3Q$ [ietf[.]org]