Re: [Lsr] Relationship between ASLA and Flex Algo

[Peter Psenak <[e-mail]>]

Hi Robert,

On 22/08/2021 20:17, Robert Raszuk wrote:
> Hi Les,
> 
> Well I was not really proposing anything just making an observation. If 
> anything adding few more SABM bits for flex-algo, but frankly I can live 
> without them just fine.
> 
> In the light of Peter's response the more interesting is the invention 
> of UDABM field. It is not IETF business so how would anyone 
> accomplish multi vendor interoperability using it ?

setting a bit in UDABM can be done by any vendor. The usage of the bit 
on the Rx side is completely in hands of the user and the consuming 
application and not specified by IETF.

> 
> Question: Can I use UDABM to set bits in metrics for use with selective 
> flex-algo topologies ?

no, all flex-algo constraints are defined in the flex-algo draft.

If you want to exclude/include links in flex-algo constrained topology 
you have affinities to do that.

> 
> Even if it is "not something that IETF is going to specify" - if we 
> define something in the protocol should it be clear what is the intended 
> use case ?

section 4, rfc8919:

   "In addition to supporting the advertisement of link attributes used
    by standardized applications, link attributes can also be advertised
    for use by user-defined applications.  Such applications are not
    subject to standardization and are outside the scope of this
    document.

thanks,
Peter


> 
> Many thx,
> R.
> 
> 
> 
> On Sun, Aug 22, 2021 at 4:48 PM Les Ginsberg (ginsberg) 
> <[e-mail] <mailto:[e-mail]>> wrote:
> 
>     Robert –____
> 
>     __ __
> 
>     I have revised the subject since this is a different topic than the
>     original thread.____
> 
>     __ __
> 
>     If you want to discuss this further, please do so in the renamed
>     thread.____
> 
>     Note that I am NOT encouraging you to continue this discussion – I
>     am in full agreement with Peter. I do not think what you propose is
>     desirable or needed.____
> 
>     __ __
> 
>         Les____
> 
>     __ __
> 
>     __ __
> 
>     *From:* Robert Raszuk <[e-mail] <mailto:[e-mail]>>
>     *Sent:* Sunday, August 22, 2021 6:33 AM
>     *To:* Peter Psenak (ppsenak) <[e-mail]
>     <mailto:[e-mail]>>
>     *Cc:* Les Ginsberg (ginsberg) <[e-mail]
>     <mailto:[e-mail]>>; Ron Bonica <[e-mail]
>     <mailto:[e-mail]>>; [e-mail] <mailto:[e-mail]>
>     *Subject:* Re: [Lsr] New Version Notification for
>     draft-hegde-lsr-asla-any-app-00.txt____
> 
>     __ __
> 
>     Hey Peter,____
> 
>     __ __
> 
>          > And I will perhaps say it again that to me flex-algo is more
>         of a
>          > mechanism to build new applications then NEW APPLICATION itself.
> 
>         no, flex-algo is a single application, it's not a mechanism to
>         create
>         new applications. The fact that you can create many constraints
>         topologies using flex-algo, does not mean these should be
>         considered as
>         different apps. You have to put and keep clear borders at clear
>         places.
>         We have them defined by ASLA and by base flex-algo draft.____
> 
>     __ __
> 
>     Why each constrained topology can not be intuitively called a
>     different network application ? ____
> 
>     __ __
> 
>     Is there any real definition of "IGP application" LSR WG has
>     converged and agreed upon ? ____
> 
>     __ __
> 
>     See your take that it is implicitly defined in flex-algo draft by
>     setting one bit to it in SABM is IMO pretty weak. Maybe it would
>     hold if you forbid to use UDABM for flex-algo metrics, but I do not
>     see such restriction anywhere in flex-algo draft nor in ASLA drafts.
>     That means that implementation may allow it. ____
> 
>     __ __
> 
>     So flex algo is a single app if we use SABM, but it can be multiple
>     apps if we use UDABM ? Don't you think this is a bit loose
>     definition ? ____
> 
>     __ __
> 
>     Cheers,
>     R.____
> 
>     __ __
>