Re: Separation of configuration and control - good or bad?

[Larry Menten <lmenten@lucent.com>]

Eliot Lear wrote:

> [I am *still* not receiving netconf mail.  Please include me in 
> responses].
>
> > What I was expressing is that if you wish to, for example, delete an 
> > interface without
> > deleting one that might be created, then after you have done your 
> > "get" operation
> > you must lock the configuration to prevent, for example, another 
> > interface being created
> > by another user that will be SILENTLY deleted when you submit your 
> > delete operation.
>
> This is true if you are updating the entire configuration, or if your 
> interfaces are sequentially named on the fly.  Those circumstances do 
> exist, and some care must be taken to avoid such race conditions. 
> Locking is a viable approach to tackling the problem.  The granularity 
> of locking is something I addressed in my previous message.

As the draft currently stands, the deletion of an interface requires 
providing the complete, desired
configuration subtree to be contained in the parent element and doing a 
"replace" operation.
Do you agree that this is the implication of the design, or am I missing 
something?

> > You have missed the point. The spec forces a mechanism that makes many
> > simple configuration operations fragile and dangerous. Nothing to do 
> > with the
> > schema. All to do with the model adopted in the draft.
>
> This is just hyperbole.  Adding even a non-granular lock fixes your 
> complaint.
It wasn't meant to be hyperbole.  A design that supports 
add/delete/replace/merge
and explicitly names the target of the operation does not require as 
much locking
to assure robust management as one that expresses transactions as 
overlay/replace/merge
and leaves it to the agent to determine what target was meant.

Larry

Larry Menten               Lucent Technologies/Bell Laboratories
Phone: 908 582-4467        600 Mountain Avenue, Murray Hill, NJ  07974 USA 


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