Re: [Lsr] [draft-ietf-lsr-flex-algo-08] Clarification on ASLA usage for flex-algo

Hi, Peter,

The flex-algo draft mentions "Min Unidirectional Link Delay as defined in [
RFC7810 <https://tools.ietf.org/html/rfc7810>]". When reading RFC7810, I
found two Sub-TLVs:

4.1. Unidirectional Link Delay Sub-TLV 4.2. Min/Max Unidirectional Link
Delay Sub-TLV

Could you please clarify which one should be used? If "Min/Max
Unidirectional Link Delay Sub-TLV" is used, will the max delay carried in
the subTLV be ignored?

Thanks,
Sarah

On Fri, Aug 7, 2020 at 8:30 AM <tony.li@tony.li> wrote:

>
> Peter,
>
>
> >> . The existing description in section 5.1 indicate that legacy encoding
> (RFC7810 and RFC5305) is used for link attributes. That is not correct
> based upon section 11. To avoid ambiguity can an explicit reference be
> added for [I-D.ietf-isis-te-app]?
> >
> >
> > well, section 5.1. is correct. The Min Unidirectional Link Delay and TE
> Default metric respectively were defined in RFC7810 and RFC5305. The fact
> that we advertise them in ASLA does not change their origin.
>
>
> Could we please get a clarification in section 5.1 then?  The references
> there to 7810 and 5305 without any qualification strongly suggest that the
> encoding from those RFCs should be used.
>
>
> >> Could in section 11 be explicit reference to (e)ag, te-metric and delay
> link attributes MUST be encoded using ASLA..
> >
> > Section 11 already says:
> >
> >   Link attribute advertisements that are to be used during Flex-
> >   Algorithm calculation MUST use the Application Specific Link
> >   Attribute (ASLA) advertisements defined in [I-D.ietf-isis-te-app] or
> >   [I-D.ietf-ospf-te-link-attr-reuse].
> >
> > I'm not sure what else can we say. Listing the ones we use today wold be
> dangerous, because we may define additional ones later and we want the ASLA
> to be mandatory for all of them.
>
>
> You could add a sentence that says:
>
>         In particular, the Min Unidirectional Link Delay, TE Default
> Metric, Administrative Group, Extended Administrative Group, Shared Risk
> Link Group Value TLVs are all to be encoded iin the ASLA advertisements for
> use with FlexAlgo.
>
> Please add any I missed.
>
> Regards,
> Tony
>
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