Hi - It is with no little amusement that I watch this thread struggling with questions that were solved fairly neatly a quarter century ago in GDMO/CMIP-land. I'm *not* suggesting we go back there, but would like to offer an observation about modeling that might help.
The organization of instance data in SNMP is a direct mirror of the "object" definitions. Simple at first, but quickly becoming baroque as various minds of "multiplexing" are added to compensate for post hoc deficiencies in the index structures. Life is such that once a resource has been modeled, it will be used/re-used/embedded in systems in ways in which its designers couldn't be expected to imagine. A consequence of this is that if instance naming is completely locked down when the management interface for a resource is first defined (as it is in SNMP) then all sorts of peculiar hacks will be needed to deal with, for example, virtual routers. Unfortunately, an SNMP/SMI-like mindset is so pervasive that folks seem to overlook that there are other ways to deal with this situation. What GDMO did was to use a separate "NAME BINDING" construct to specify contexts in which instances might show up, allowing instances to be put in places that weren't even imagined when the original class definition was written. Name bindings could be standardized, or be vendor or even product-specific, allowing the simplicity or complexity of a given system's instance tree to reflect the actual simplicity or complexity of that system, rather than requiring all systems to be structured for the worst case. Yes, separating the specification of instance naming in large part from class definition does have implications for how one does access control, and how clients figure out how to ask a server to create something, but it's not a huge deal - it's just not like VACM, and a whole slew of hacky solutions and "wierd plumbing adapters" (to borrow from Jeff Case) just go away. Strangely, it makes the job of the initial modeler and of the eventual user much easier. Randy _______________________________________________ netmod mailing list [email protected] https://www.ietf.org/mailman/listinfo/netmod
