Re: [Detnet-dp-dt] New update of the draft available

[Balázs Varga A <[e-mail]>]

Hi Loa,

I think the addition of the DetNet Flow-ID to the "PW Encapsulation header" changed 
our former discussions. If the DetNet Flow-ID is present, we can change the d-pw label 
during the transport like in case of a legacy MS-PW.

Also we assume no protection other than PRER for DetNet flows (see also the 
draft-architecture, section 3.2).
" 3.2. Explicit routes
... DetNet employs
explicit routes, where the path taken by a given DetNet flow does not
change, at least immediately, and likely not at all, in response to
network topology events. Service protection (Section 3.4 or
Section 3.5) over explicit routes provides a high likelihood of
continuous connectivity. "

> d-pw label with signaling that exposes the "request for DetNet NSP/FRER" to P nodes
Could You explain it more, I do not see your point. Do You propose that the L-label value
would control whether a PW is a DetNet PW with PRER or not?

Thx & Cheers
Bala'zs

-----Original Message-----
From: Detnet-dp-dt [mailto:[e-mail]] On Behalf Of Loa Andersson
Sent: Saturday, March 11, 2017 3:38 AM
To: [e-mail]
Subject: Re: [Detnet-dp-dt] New update of the draft available

Jouni,

Mostly looks very good, the thing I don't understand is why you still say that the L-label is optional, it really isn't.

- we need it to deliver the d-pw label unchanged
- since we can't guarantee that the "P" nodes are not able to do
   DetNet NSP, we can't set up the d-pw label with signaling that
   exposes the "request for DetNet NSP/FRER" to P nodes.
- needed for protection
- the end-to-end tunnel must be the innermost tunnel, carrying
   pw label

There is one case, if two DA-*-PEs are immediately adjacent, there the L-lable will be an implicit NULL label and not appear in the stack, but for the control plane it is there.

/Loa

On 2017-03-11 07:25, Jouni Korhonen wrote:
> * Added Loa’s comments on the L-label.
> * Added Janos’ comments.
> * Added extended forwarder text.
> * Added (speculative text.. can be removed) D bit to flow-id word so 
> that we can check in a ring case the direction of the flow (note this 
> does not double history buffer space as claimed.. did not bother to 
> fix that)
> * reworked the PW encapsulation pictures.
> * Added more content to DA-*-PE descriptions.
>
> - Jouni
>
>

-- 


Loa Andersson                        email: [e-mail]
Senior MPLS Expert                          [e-mail]
Huawei Technologies (consultant)     phone: [phone]

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