Re: [Detnet-dp-dt] quick notes from 1/24/17 call

[Jouni Korhonen <[e-mail]>]

Lou,

> On Jan 25, 2017, at 1:48 PM, Lou Berger <[e-mail]> wrote:
> 
> 
> 
> On 1/25/2017 3:47 PM, Jouni Korhonen wrote:
>> --
>> Jouni Korhonen, Broadcom Ltd.
>> M: [phone]
>> 
>>> On Jan 25, 2017, at 12:44 PM, Lou Berger <[e-mail]> wrote:
>>> 
>>> Jouni/Team,
>>> 
>>>   Sounds like good progress. A couple of questions:
>>> 
>>> - I see you thinking about CoS,  That's good.  Have you thought about
>>> how QoS (flow specific resource allocation) is tagged/managed?
>> Not yet. One possibility would be associating this to the “detnet PW” label, but haven’t really looked into that yet.
> Mapping a PW down to an mpls service label (before the transport label)
> would fit with existing architecture, and I bet hardware.  You could
> even use SR underneath. 
> 
>>> - Have you had any discussions yet about DetNet without MPLS, i.e.,
>>> DetNet flows over IP? If so, what are you thinking?
>> Nothing yet. We have been very MPLS biased.
> 
> That's fine.  One concern I have is if detnet specific functions rely on
> a CW or detnet label, that it can't be made to work with IP while the
> converse wouldn't be true.  Of course there's the alternative that IP
> hosts would implement basically PW transport  over IP. 

That’s what I have had in mind i.e., DetNet over IP is actually just a PW with IP PSN. I cannot speak for others, though.

> The real point here is a gentle reminder that DetNet service over IP is
> in scope for the DT...

Sure. We’ll keep this also in pipe.

- Jouni


> 
> Thanks for the quick reply!
> 
> Lou
> 
>> 
>> - JOuni
>> 
>>> Thanks,
>>> 
>>> Lou
>>> 
>>> PS I will make it to one of these calls at some point...
>>> 
>>> On 1/25/2017 11:44 AM, Jouni Korhonen wrote:
>>>> Folks,
>>>> 
>>>> We had a +1h call last night. Participants: Jouni, Carlos, Loa, Norm, Yuanlong, Janos and Tal.
>>>> 
>>>> For the discussion refer to Loa’s slides sent to the DT list on 1/13/17.
>>>> 
>>>> We seemed to have reached consensus on PWs and three label approach i.e., transport label + PW label + “detnet PW” label (d-pw in slides and this one is associated with the seqnum). The “detnet PW” label is end to end between detnet flow end points and unique within the detnet domain. This arrangement will cause 16 octet overhead (3x label + cw):
>>>> 
>>>> +-----------------+
>>>> | Transport Label | --> per each LSR; top of stack
>>>> +-----------------+
>>>> | PW Label        | --> per each PW (between T-PEs and/or S-PEs)
>>>> +-----------------+
>>>> | Detnet PW Label | --> between DetNet end points
>>>> +-----------------+
>>>> | CW - 28 bit sn  | --> associated with DetNet PW label 
>>>> +-----------------+
>>>> | Payload         | --> whatever we transport
>>>> +-----------------+
>>>> 
>>>> Multiplexing: one transport label may transport PW labels, and one PW label may transport multiple “detnet PW” labels.
>>>> 
>>>> The (virtual) network topology (LSP paths) can be programmed at the PW level. This means any detnet flow can use those without having to setup path individually for each “detnet PW”. As a consequence adding new detnet flows to system is enable i.e., when the duplicate detection and elimination function sees a new “detnet PW” label, it can instantiate new function to deal with duplicate detection and elimination - dynamically. 
>>>> 
>>>> We started the discussion on class of service and how that could be arranged in a label stack. The CoS could use the EXP bits on the transport label. However, it needs to be checked whether/how different CoS could be “propagated” through the label stack e.g., in a case where “detnet PW” labels/flows have different CoS needs. Need to check whether this is sufficient as a way forward.
>>>> 
>>>> Need some more thinking:
>>>> * CoS (see above)
>>>> * Any need for timestamps (we did not discuss this, but see IETF97 presentation about RTP headers)?
>>>> 
>>>> Next call:
>>>> Tue 1/31/2017 the usual time.
>>>> 
>>>> 
>>>> --
>>>> Jouni Korhonen, Broadcom Ltd.
>>>> M: [phone]
>>>> 
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>> 
>