RE: Referential integrity across reboots

["STEPHAN Emile FTRD/DAC/LAN" <emile.stephan@rd.francetelecom.com>]

Hi,


In the IPPM REPORTING MIB we use an index value choosen in an owner
namespace to preserve the index of a measure accross the reboots and
among the points of measure.

regards
Emile

> -----Message d'origine-----
> De : Mark Ellison [mailto:ellison@ieee.org]
> Envoye : samedi 27 juillet 2002 12:43
> A : mibs@ops.ietf.org
> Cc : Randy Presuhn
> Objet : Re: Referential integrity across reboots
> 
> 
> Hi Randy,
> 
> I have also encountered the described issues with respect to VACM
> configuration and ifIndex and entPhysicalIndex.  When multiple
> administrations need access to thier rows in a shared table, then
> instances must be part of the VACM configuration, and, index values
> within applicable portions of the shared table must persist 
> in order to
> expereience VACM consistency.
> 
> The solution, as Andy described, is to persist index/instance values
> across reboots.
> 
> For ifIndex, we've used an architectural range of values for physical
> interfaces (which MAY change across reboot, or as a result of a
> component hot-swap), and a range of values for virtual interfaces.  It
> turned out these virtual interface instances contain the persistent
> configuration data which was to be accessible to various
> administrations, so index values for these instances MUST 
> persist across
> reboots if the VACM constraints are to work properly.
> 
> An interesting side effect of an agent persisting  index 
> values is that
> it simplifies management applications deriving performance 
> and trending
> information from agent data across reboots.
> 
> Regards,
> 
> Mark Ellison
> Ellison Software Consulting, Inc.
> 
> 
> 
> Randy Presuhn wrote:
> 
> > Hi -
> >
> > A problem has popped up in a couple of working groups needing
> > to handle persistant configuration data.
> >
> > An example of the basic problem is that VACM is based on the
> > assumption that the name of an object instance to which access
> > is to be controlled will remain the same across reboots.
> > For objects whose names change, like table entries indexed
> > with ifIndex, fine-grained access control becomes problematic.
> >
> > However, it's not just a problem with VACM.  It shows up
> > anywhere where we can have things like row or instance pointers
> > as configuration data that needs to survive a reboot, and
> > those pointers can reference objects whose names might change.
> > So, for example, the event mib, the alarm mib, the arc mib,
> > the expression mib, the notification filtering in RFC 2573,
> > rmon's thresholding, and nmpconf pm mib scripts are just a
> > few examples of things that could run afoul of this.
> >
> > Thoughts?
> >
> >  ------------------------------------------------------
> >  Randy Presuhn          BMC Software, Inc.  1-3141
> >  randy_presuhn@bmc.com  2141 North First Street
> >  Tel: +1 408 546-1006   San Jose, California 95131  USA
> >  ------------------------------------------------------
> >  My opinions and BMC's are independent variables.
> >  ------------------------------------------------------
> 
> 
> 
>