Re: [DLNEX] [Detnet] FW: New Non-WG Mailing List: DLNEX -- Discussion of reliable and deterministic latency attributes

[Linda Dunbar <[e-mail]>]

Pat,

What you said is so true: “The network can't provide a bounded or deterministic latency to an unbounded flow”.

DETNET charter starts with
The Deterministic Networking (DetNet) Working Group focuses on
deterministic data paths that operate over Layer 2 bridged and Layer 3
routed segments, where such paths can provide bounds on latency, loss,
and packet delay variation (jitter), and high reliability

If I understand it correctly, DETNET focuses on the enabling technologies to ensure deterministic latency path across a set of nodes.

E2E low latency services has many issues, such as:

·        There could be “bounded flows” that need low latency services mixed with other traffic in the network.

·        E2E services may have to go through many hops, links with some links not supporting DETNET.

·        there could be various protection/re-route mechanisms which all increase latency.

·        etc

Some problems specific to WAN include how to isolate the various service traffic, and provide maximum manageability to upper layers.

One company in NANOG asked why not use ICMP to mark the delay along the path to give upper link, ..

Linda


Linda

From: Pat Thaler [mailto:[e-mail]]
Sent: Wednesday, October 19, 2016 5:25 PM
To: Lou Berger <[e-mail]>
Cc: Alia Atlas <[e-mail]>; Patrick Wetterwald (pwetterw) <[e-mail]>; [e-mail]; Pascal Thubert (pthubert) <[e-mail]>; [e-mail]; [e-mail]; Linda Dunbar <[e-mail]>
Subject: Re: [Detnet] FW: New Non-WG Mailing List: DLNEX -- Discussion of reliable and deterministic latency attributes

We have been having recent discussions about latency such as what type of latency is important.

As far as the "feasibility exercise for achieving reliable and deterministic latency through a network element or a segment" that overlaps very much what DetNet and IEEE 802.1 TSN have been doing. I believe we have already shown that it is feasible and are not on specifying how to do that. I'm concerned about the overlap between what that paragraph describes and our work.

There could be useful work on communication from the upper layer of the flow characteristics, behavior and requirements. There probably is some gap to fill that would help our work. I'm concerned that the list description focuses only on exposing lower layer characteristics to the upper layer. The network can't provide a bounded or deterministic latency to an unbounded flow - to determine what latency can be provided, one has to know something about the bandwidth utilization of the flow.

Regards,
Pat

On Wed, Oct 19, 2016 at 1:59 PM, Lou Berger <[e-mail]<mailto:[e-mail]>> wrote:
Hi Alia,

    Overlap looks likely.  I hope that when it does occur, you send
folks over here to contribute -- additional input / WG participation
would be great!  (For folks not familiar with DetNet, check out our
charter at https://datatracker.ietf.org/wg/detnet/charter/)

I expect we'll have some good data plane centric discussions at this
meeting, for those who may be interested (there's even still time to
submit related drafts!)

Cheers,

Lou

DetNet Co-chair

On 10/19/2016 11:46 AM, Alia Atlas wrote:
> Hi Patrick,
>
> The discussion intended on dlnex, a non-WG mailing list, is, I think,
> broader - spanning the range of communications between upper layer
> applications and the network.  It is not clear yet what work might
> develop.  Be sure that I will be watching for any specific overlap
> with DetNet.
>
> I feel that it is useful to make it easy for groups to have a list to
> brainstorm about their ideas before work is mature enough to consider
> for standardization.
>
> Regards,
> Alia
>
> On Wed, Oct 19, 2016 at 8:17 AM, Patrick Wetterwald (pwetterw)
> <[e-mail]<mailto:[e-mail]> <mailto:[e-mail]<mailto:[e-mail]>>> wrote:
>
>     Can someone explain me why this mailing list is created outside of
>     DetNet?
>
>     This sounds like a subset of Detnet no?
>
>     Thanks,
>
>     Patrick
>
>
>     On 19/10/2016, 07:56, "detnet on behalf of Pascal Thubert
>     (pthubert)" <[e-mail]<mailto:[e-mail]>
>     <mailto:[e-mail]<mailto:[e-mail]>> on behalf of [e-mail]<mailto:[e-mail]>
>     <mailto:[e-mail]<mailto:[e-mail]>>> wrote:
>
>         From: IETF-Announce [mailto:[e-mail]<mailto:[e-mail]>
>     <mailto:[e-mail]<mailto:[e-mail]>>] On Behalf Of IETF Secretariat
>         Sent: mardi 18 octobre 2016 22:36
>         To: IETF Announcement List <[e-mail]<mailto:[e-mail]>
>     <mailto:[e-mail]<mailto:[e-mail]>>>
>         Cc: [e-mail]<mailto:[e-mail]> <mailto:[e-mail]<mailto:[e-mail]>>;
>     [e-mail]<mailto:[e-mail]> <mailto:[e-mail]<mailto:[e-mail]>>; [e-mail]<mailto:[e-mail]>
>     <mailto:[e-mail]<mailto:[e-mail]>>
>         Subject: New Non-WG Mailing List: DLNEX -- Discussion of
>     reliable and deterministic latency attributes
>
>
>         A new IETF non-working group email list has been created.
>
>         List address:[e-mail]<mailto:[e-mail]> <mailto:[e-mail]<mailto:[e-mail]>>
>         Archive:
>     https://mailarchive.ietf.org/arch/search/?email_list=dlnex
>     <https://mailarchive.ietf.org/arch/search/?email_list=dlnex>
>         To subscribe: https://www.ietf.org/mailman/listinfo/dlnex
>     <https://www.ietf.org/mailman/listinfo/dlnex>
>
>         Purpose:
>         DLNEX is to discuss various latency characteristics that can
>     be exposed by network elements or segments and to explore if there
>     are any latency related attributes that can be utilized by upper
>     layer. For example, could there be latency exposure that upper
>     layer can utilize to plan how to distribute their content to the
>     right edges to achieve optimal user experience? Or something used
>     by Interactive AR controller to optimize their services? Is there
>     any value gained by upper layer expressing that they would rather
>     have fixed latency than losing packets?
>
>         The discussion is to answer questions like: are there any
>     effective interaction/coordination between upper layer and lower
>     layer to achieve more efficient optimization for latency sensitive
>     services?
>
>         This discussion group is also a place to showcase the state of
>     the arts in latency optimized switching architecture and interface
>     designs, as the feasibility exercise for achieving reliable and
>     deterministic latency through a network element or a segment.
>     Those latency exposures are the foundation for (future) latency
>     optimized control plane.
>
>
>         For additional information, please contact the list
>     administrators.
>
>         _______________________________________________
>         detnet mailing list
>         [e-mail]<mailto:[e-mail]> <mailto:[e-mail]<mailto:[e-mail]>>
>         https://www.ietf.org/mailman/listinfo/detnet
>     <https://www.ietf.org/mailman/listinfo/detnet>
>
>
>     _______________________________________________
>     detnet mailing list
>     [e-mail]<mailto:[e-mail]> <mailto:[e-mail]<mailto:[e-mail]>>
>     https://www.ietf.org/mailman/listinfo/detnet
>     <https://www.ietf.org/mailman/listinfo/detnet>
>
>
>
>
> _______________________________________________
> detnet mailing list
> [e-mail]<mailto:[e-mail]>
> https://www.ietf.org/mailman/listinfo/detnet

_______________________________________________
detnet mailing list
[e-mail]<mailto:[e-mail]>
https://www.ietf.org/mailman/listinfo/detnet