Re: [Detnet-dp-dt] quick notes from 1/31/17 call

[Jouni Korhonen <[e-mail]>]

Loa,

> On 05 Feb 2017, at 20:13, Loa Andersson <[e-mail]> wrote:
> 
> Jouni and Carlos,
> 
> Please see inline
> 
> On 2017-02-06 11:29, Jouni Korhonen wrote:
>> 
>> Carlos,
>> 
>> 
>>> On 05 Feb 2017, at 03:56, Carlos Jesús Bernardos Cano <[e-mail]> wrote:
>>> 
>>> Hi Jouni, all,
>>> 
>>> Thanks for the minutes and apologies for not joining this time.
>>> 
>>> I have a couple of questions:
>>> 
>>> 1. For the transport, we have so far assumed MPLS and IP PSNs (focusing
>>> the discussion mainly on MPLS until this week). Are we restricted to
>>> only these two? I think in some use cases other transports such as
>>> MPLS-TP can be relevant as well. Will we explore this too/make the
>>> solution open enough to support other transports?
> 
> The relationship between the MPLS transport profile and MPLS is that MPLS-TP is a true subset of MPLS, i.e. anything new that was defined for
> MPLS-TP is also applicable for MPLS. On the other hand MPLS-TP explicitly excluded a couple of things that is part of MPLS. The two
> most important things that were excluded was that
> (1) you can not assume the presence of IP or IP routing in MPLS-TP
> (2) PHP is always disabled

Yes... and? I think you cannot assume the presence of IP in a case detnet either, and PHP can always be turned off my configuration.

> 
> The DetNet charter says:
> 
> The Deterministic Networking (DetNet) Working Group focuses on
> deterministic data paths that operate over Layer 2 bridged and Layer 3
> routed segments, ...
> 
> Since MPLS-TP is neither "Layer 2 bridged" or "Layer 3 routed". to me
> it looks like MPLS-TP is excluded.

I don’t quite get the conclusion here. Maybe I am thinking too simple but for me MPLS-TP in DetNet DP case is just labels.

- Jouni


> 
> /Loa
> 
> 
>> 
>> Most of the DetNet DP “sauce” is on the PW layer. We already assured that the PSN can be either a LSP or IP. Since MPLS-TP includes PWE is see no reason why “MPLS-based” PSN could not also be implemented using MPLS-TP.
>> 
>>> 2. How are organizing to work on the first draft text? I'm available to
>>> contribute text.
>> 
>> I’ll get the first round up soon. Then we can divide the job into sections that everybody (volunteering) is responsible for.
>> 
>> - Jouni
>> 
>> 
>> 
>>> 
>>> Thanks!
>>> 
>>> Carlos
>>> 
>>> On Wed, 2017-02-01 at 18:02 -0800, Jouni Korhonen wrote:
>>>> Present: Jouni, Loa, Norm, Balazs, Janos, Tal and David.
>>>> 
>>>> See the attached slideset that was used as the basis during the call.
>>>> The MPLS-based PWE encaps has matured, except for: 1) fine grained
>>>> CoS (i.e., 802.1 has discussed finer granularity of CoS basically to
>>>> a flow level. The flow identification mechanism in .1CB, .1Qci et al
>>>> allows this), and 2) PW CW SN width. We have discussed using 28 bits
>>>> but that might cause issues when interworking with systems that only
>>>> understand 16 bits (HSR and PRP as an examples).
>>>> The CoS part and whether TC bits are copied between layers is still
>>>> to be discussed further.
>>>> IP PSN seems OK. The questions on the slides were discussed:
>>>> - PW labels are still good to have. It makes the stack/implementation
>>>> more streamlined between MPLS and IP PSNs. Also PW labels make PW
>>>> switching way easier e.g., in a case of replication/elimination.
>>>> - In a case of IP PSN each PW will have their own “tunnel” between T-
>>>> /S-PEs. That means e.g., a PW between A and B will have different
>>>> src/dst addresses than a PW between B and D. This makes pinned down
>>>> paths easier to realize using IP PSN.
>>>> 
>>>> Norm asks for the cases where DetNet interworks with e.g. 802.1TSN.
>>>> Would there be a way to regenerate MAC addresses if those are not
>>>> transported over DetNet (this is for the case where the L2 is just so
>>>> bug that interconnect does not make sense). Discussion.. Jouni
>>>> commented that it is not in current document’s scope. Could be worked
>>>> in parallel once the encaps for DetNet DP mature a bit.
>>>> 
>>>> Loa comments that EXP bits in an MPLS labels should use TC instead
>>>> (Traffic Class), see RFC5462.
>>>> 
>>>> Jouni commented that we now start to have enough material to produce
>>>> a draft of a draft. Expect the first version next week.
>>>> 
>>>> Quick discussion on 1588 PTP in DetNet. 1588 packets should not be
>>>> replicated. Actually using DetNet encapsulation for them is not
>>>> really a good idea. Tal will educate us more on that next time.
>>>> 
>>>> Action points:
>>>> Tal will produce a slideset regarding his thoughts/concerns on 1588
>>>> transport in DetNet.
>>>> 
>>>> Next call: 2/7/17 10PM PDT
>>>> 
>>>> 
>>>> --
>>>> Jouni Korhonen, Broadcom Ltd.
>>>> M: [phone]
>>>> 
>>>> _______________________________________________
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>>>> https://www.ietf.org/mailman/listinfo/detnet-dp-dt
>> 
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> 
> -- 
> 
> 
> Loa Andersson                        email: [e-mail]
> Senior MPLS Expert                          [e-mail]
> Huawei Technologies (consultant)     phone: [phone]