Re: [secdir] SECDIR review of draft-ietf-l2vpn-vpls-inter-domain-redundancy-05

[Lizhong Jin <[e-mail]>]

Hi Adrian,
OK with the proposal. Thanks.

Regards
Lizhong

On Thursday, April 17, 2014, Adrian Farrel <[e-mail]> wrote:

> Hello,
>
> Just pitching in on one of the points...
>
> >>> Section 5 ends with a curious statement:
> >>>
> >>>  There are two PW redundancy modes defined in [RFC6870]:
> >>>  Independent mode and Master/Slave mode.  For the inter-
> >>>  domain four-PW scenario, it is required for PEs to ensure
> >>>  that the same mode is supported on the two ICCP peers in
> >>>  the same RG.  One method to ensure mode consistency is by
> >>>  manual operation.  Other methods are also possible and are
> >>>  out of the scope of this document.
> >>>
> >>> This says that two ASes have to ensure that both employ the
> >>> same redundancy mode choice, notes that they can verify
> >>> this manually, and that says there are other options to meet
> >>> this requirement, but provides no description of the other
> >>> options.  Not very useful.
> >>
> >> [Lizhong] I think the text is OK. If you insist, I could remove.
> >
> > the text is not OK, because its states that there are multiple
> > ways to ensure consistency, but  identifies only one.
>
> We had a bit of a go at this text during AD review, and I may be
> responsible for
> it getting into this state.
>
> Previously the document just said that it was required for PEs to ensure
> the
> same mode was in use. I insisted that some description of how this was
> done was
> added. I don't consider manual operation to be a very good solution
> (because of
> the likely errors that will arise), but it is undoubtedly *a* solution.
>
> I don't believe the current text says that there exist other ways of
> meeting the
> requirement. The text uses the word "other methods are also possible"
> which is
> inevitably true. Yet it is also the authors' contention that so long as *a*
> method has been provided, other methods can be out of scope of this
> document (I
> am sure they would be happy for people to invent new mechanisms, it's just
> that
> they don't feel the need).
>
> So, "not very useful", but not false or misleading.
>
> We could probably dilute the text to read:
>
>   There are two PW redundancy modes defined in [RFC6870]:
>   Independent mode and Master/Slave mode.  For the inter-
>   domain four-PW scenario, it is required for PEs to ensure
>   that the same mode is supported on the two ICCP peers in
>   the same RG.  This can be achieved using manual configuration
>   at the ICCP peers. Other methods for ensuring consistency are
>   out of the scope of this document.
>
> Thanks to you both for the work.
>
> Adrian
>
>