Re: [Detnet-dp-dt] detnet LSPs and PWs

["Andrew G. Malis" <[e-mail]>]

Loa et al,

To be clear, there’s currently no definition of PWs encapsulated in PWs,
and while it might be conceptually possible, such as an Ethernet PW carried
within a SONET/SDH PW, I couldn’t imagine a use case for doing it as it’s
very inefficient, and I asked Loa if he had one. And if you were to do so,
each PW in the hierarchy would need NSP functionality and real or emulated
CE access circuits at the endpoints. Also, thinking about it some more, you
couldn’t have both PWs in the same label stack, since a PW emulates a
physical circuit. So there would need to be a separate label stack (and
MPLS LSP) inside the emulated circuit for the outer PW. By definition, PW
labels terminate a label stack.

As I haven’t been following Detnet at all, I don’t have the context for
what you’re trying to accomplish. That said, I’ll take a look at the slides
and let you know if I have any comments.

Cheers,
Andy


On Sun, Feb 12, 2017 at 8:31 PM, Loa Andersson <[e-mail]> wrote:

> Folks,
>
> The mail from Yuanlong mmade me go back and check the PW architecture and
> consult with Andy Malis and Stewart Bryant. So I have one more thing
> that we should discuss on "Tuesday".
>
> What Yaunlong said was: "IMHO, multiple layers of PW is a break from
> the PWE3 architecture, and all DP/CP/MP things will become more
> complicated."
>
> It is correct that multi-layer pw's is problematic, though Andy said
> that "if you have a good use case, you can do it".
>
> The problem is that there is a native service processing (NSP) at the end
> of the PW. Multi-layer PWs will only do NSP at one level. I think
> we should replace the MS-PW with an LSP. I've added one slide (9) and
> change slide 8,9 and 11 in the earlier package. The other slides arere
> for reference
>
> I want Andy and Stewart to have a chance to review this prior to that
> we commit too hard to it. Copied them.
>
>
> /Loa
> --
>
>
> Loa Andersson                        email: [e-mail]
> Senior MPLS Expert                          [e-mail]
> Huawei Technologies (consultant)     phone: [phone]
>