Robert Raszuk <[email protected]> writes:

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. 

This is purely user interface code, you can do this w/o changing the on the 
wire standard encoding.

Thanks,
Chris.
[as wg-member]

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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