Hi Chris,

It seems that there is a subtle but important element on which we may have
different opinion.

You said: "has to deploy new software that contains the new Wizbang
feature, right?"

IMO however we are dealing with case where software already supports all
required functions on a box. It is just not using it from day one. You buy
a router with OS features which allow you to build zoo of different
forwarding paradigms.

Say day one you see a need to enable flex-algo_1 You enable day one links
to distribute link attributes required for this.

Day two you want to define new FAD and flood this enabling new flex-algo_2.
You reuse already present link attributes entirely or partially in
flex-algo_2 computation. You do not need to touch 100000s of links each
time you enable new flex_algo.

That's a selling point to me.

If we would expect that folks will limit flex-algo to just a few maybe this
all does not matter. But if we see proposals with rainbow of colors each
mapped to different flex-algo and perhaps subtle forwarding difference
(same metric but just a different min threshold per each flex-algo) it
seems pretty bad idea to explicitly enable each app each time such new
threshold used to build different topology.

Example:

link attribute:  delay

applications:

flex-algo_1 - build topology where max delay does not exceed 10 ms - color:
premium best effort
flex-algo_2 - build topology where max delay does not exceed 8 ms -  color:
black
flex-algo_3 - build topology where max delay does not exceed 6 ms - color:
bronze
flex-algo_4 - build topology where max delay does not exceed 4 ms - color:
blue
flex-algo_5 - build topology where max delay does not exceed 3 ms - color:
silver
flex-algo_6 - build topology where max delay does not exceed 3 ms - color:
gold

etc ...

Now tell me how does it make sense to enable each app on the link delay
attribute ?

Cheers,
Robert



On Sat, Mar 26, 2022 at 6:42 AM Christian Hopps <[email protected]> wrote:

>
> Robert Raszuk <[email protected]> writes:
>
> > Les,
> >
> > I don't think this is noise.
> >
> > Your examples are missing key operational consideration .. Link
> > attribute applicable to ANY application may be advertised well ahead
> > of enabling such application in a network.
> >
> > So requesting operator to always advertise tuple of app + attr is not
> > looking forward and makes unnecessary operational burden.
>
> [as wg-member]
>
> Hi Robert,
>
> Originally this was the argument that sort of put wind in the sails (for
> me) for this any bit, but some more thinking about how things would really
> work changed my mind.
>
> In order for some new feature, let's call it Wizbang, to take advantage of
> existing any bit marked attributes, the operator still has to deploy new
> software that contains the new Wizbang feature, right? So the addition of a
> new Wizbang bit pretty much comes free for the operator.
>
> So, this draft really is just about making the encoding a bit more
> efficient.
>
> I think if we were defining a new encoding, having this functionality
> makes sense, but we aren't defining a new encoding. The proposal is to
> change an existing published encoding, and the bar has to be higher for
> that I think.
>
> Thanks,
> Chris.
> [as wg member]
>
>
> >
> > Thx.
> > R.
> >
>
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