Re: [YANG] default values

[Balazs Lengyel <[e-mail]>]

Hello,
I think you are arguing about different things. As I understand your comments:
Statement 1) says: defaults are important, so if we do have an agreed default value, we should 
document it in a proper, formal way. (I fully support this.)
Statement 2) says: it is very difficult to agree on good default values so we should use 
extreme caution specifying "mandatory" defaults in standards. I can agree with that as well.
We can still to define recommended-only defaults in the description statement if the default is 
not obvious enough.

The two statements do not contradict each other in my view.

Also while it is difficult to define default values in standards, YANG and NETCONF will be used 
a lot to define proprietary data models as well. It is much easier to define defaults here, and 
yes we do want a formal definition of these defaults (actually we already have it in the 
Ericsson-DML.)

Balazs


Ladislav Lhotka wrote:
> Jon Saperia píše v St 16. 01. 2008 v 11:54 -0500:
> 
>> I understand your perspective but even  though I said what I said, if  
>> we were to go down this path, defaults can be helpful.  Any manager  
>> that attempts the configuration function will have to be pretty  
>> sophisticated because of the variability (even with standards) that  
>> will be sure to exist. That does not mean that they will not do bad  
>> things from time to time, but the market has a way of fixing things.
> 
> I am not against specifying defaults (reasonably), I only don't like the
> fact that changing a default value implies a different data model. I
> understand the data model primarily as a means for checking whether a
> given document is valid or not and default values are irrelevant in this
> respect. It is already difficult to standardise the knobs and default
> values are yet another level.
> 
> Lada
> 
>> /jon

-- 
Balazs Lengyel                       Ericsson Hungary Ltd.
TSP System Manager
ECN: 831 7320                        Fax: [phone]
Tel: [phone]     email: [e-mail]


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