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

[Larry Menten <lmenten@lucent.com>]

Brendan Kelly wrote:

>  
> > -----Original Message-----
> > From: Phil Shafer [mailto:phil@juniper.net]
> > Sent: Friday, May 16, 2003 7:26 AM
> > To: Juergen Schoenwaelder
> > Cc: netconf@ops.ietf.org
> > Subject: Re: Separation of configuration and control - good or bad?
> >
> > Juergen Schoenwaelder writes:
> >    
> > > It seems to work in other places, so why not here?
> > >      
> > Not that it can't work, just a matter of ease. If I want to pull
> > down a configuration, do some changes to it and hand it back to the
> > device, it's nice to have the format I hand back to the device be
> > the same as what the device gave me.  This allows simple transformations
> > (ala xslt) in the pattern of:
> >
> >   $config = $jnx->get_configuration();
> >   $new = transform($config, $stylesheet);
> >   $jnx->load_configuration($new);
> >
> >    
>
> Phil's approach also lends itself well to tools which provide deltas on xml
> documents.
> <configuration>
> 	<rip somenamespace:delta="add">
> 		<version>2</version>
> 		<redistribute>
> 			<connected/>
> 		</redistribute>
> 		<network>172.22.0.0</network>
> 	</rip>
> </configuration>
>  
I'd say that that captures the difference.  The Enns model is one in which
configuration is expressed as the transformation of a document.  This is why
you must lock the document before you operate on it.  There is a race 
condition
between the get_configuration and the load_configuration.

I prefer a model in which you explicitly name the target of the 
operation and
you provide only that data relevant to the operation.  The Enns document 
uses
"replace" to delete an element, requiring that all of the siblings of 
the deleted
element must be provided in the transaction even though the intention is 
not to
modify them.  Futhermore, you must now verify that those sibling trees 
to not also
express a configuration change. More unneccessary processing in the agent. 
Seems to me that that is a very indirect way to manage a device.

>  
> > Thanks,
> > Phil
> >
> > --
> > to unsubscribe send a message to netconf-request@ops.ietf.org with
> > the word 'unsubscribe' in a single line as the message text body.
> > archive: <http://ops.ietf.org/lists/netconf/>
> >    
>  
--
Larry Menten               Lucent Technologies/Bell Laboratories
Phone: 908 582-4467        600 Mountain Avenue, Murray Hill, NJ  07974 USA 


--
to unsubscribe send a message to netconf-request@ops.ietf.org with
the word 'unsubscribe' in a single line as the message text body.
archive: <http://ops.ietf.org/lists/netconf/>