Re: [eman] Entity identification method

[Benoit Claise <[e-mail]>]

Hi Juergen,

draft-parello-eman-energy-aware-mib has its own pmIndex index, but also 
pmPhysicalEntity (as a non index MIB object) if the ENTITY-MIB is supported.
Isn't it the best of both worlds?
If the ENTITY-MIB is not supported, the pmIndex does its job.
If you need to report on the remote entities, the pmIndex does its job.
If the ENTITY-NIB is supported, then the pmPhysicalEntity contains the 
pointer to the ENTITY-MIB

Btw, the same principle has been applied for the Power Ethernet MIB 
[RFC3621] with pmEthPortIndex and pmEthPortGrpIndex 
PethPsePortGroupIndexOrZero.
And again with the [LLDP-MIB 
<http://tools.ietf.org/html/draft-parello-eman-energy-aware-mib-00#ref-LLDP-MIB>] 
and [LLDP-MED-MIB 
<http://tools.ietf.org/html/draft-parello-eman-energy-aware-mib-00#ref-LLDP-MED-MIB>] 
with pmLldpPortNumber

See inline.
> Hi Benoit and all,
>
> I agree that we should find a common identification method
> for entities used by all MIB modules. This does not apply to
> the POWER MIB only, but to all MIB modules in the eman WG.
> The modules will use an entity ID as index for their tables.
> Which entity is identified by the index can be resolved by
> other MIB modules, such as the POWER AWARE MIB module
> (draft-parello-eman-energy-aware-mib) or the ENTITY MIB
> module (RFC 4133).
> I see three basic scenarios for the entity identification:
>
>    a) a device just reports on its own power state and energy
>       consumption and it reports on its own as a single unit.
>
>       Then we have a single index only stating "it's me".
>       Such a device usually does not need further identification
>       of itself, because typically there are sufficient other
>       MIB modules for this purpose running in the same SNMP engine,
>       that provide information about the device's IP address,
>       manufacturer, operating system, etc. In such a case a
>       'trivial' index, such as '0' should be used in order to
>       keep it simple in this most simple case.
>
>    b) a device reports on its own but not just as a single unit
>       but it reports power states and energy consumption for its
>       individual components, for example it may report separately
>       on contained hard drives, line cards, back planes,
>       processor boards, etc.
>
>       In such a case, identification of these components as
>       individual entities would be required. The ENTITY MIB
>       module was designed for this purpose and would be a good
>       choice here. Also the POWER AWARE MIB module would be
>       useful in this case.
>
>    c) a device reports on energy consumption of other, remote
>       devices. Then remote devices (and potentially also their
>       contained components need to be identified. For
>       identifying remote components there is the POWER AWARE MIB
>       module that has been designed for this purpose. As far as
>       I understand, the ENTITY MIB module is not applicable to
>       remote devices.
>
> In summary,
>    - if you need to report on remote entities (case c)),
>      you need the POWER AWARE MIB module,
>    - if you report only on entities locally contained
>      in the reporting device (case b)), you can use
>      the POWER AWARE MIB or the ENTITY MIB
>    - if you report just on your own as a single device
>      (case a)), identification is trivial
>
> Hence, my recommendation (stated for POWER-STATE MIB and
> ENERGY MIB in draft-quittek-power-mib-02) would be:
>
> If there is an implementation of the POWER AWARE MIB module
> instantiated in the local SNMP engine, then you SHOULD
> (or MUST?) use it for indexing (pmIndex).
> If this is not the case but there is an ENTITY MIB instance
> available, then you SHOULD use this one (entPhysicalIndex).
> If neither of this MIB modules is available you should use
> index 0 only and be limited to report on the local device
> as a single entity only.
Another problem that is linked: index persistence.
If the persistence is required (to be discussed), and if you use the 
entPhysicalIndex as an index in these MIB module, basically you're 
asking for the ENTITY-MIB persistence.
IMHO, another reason to have this level of indirection via the pmIndex 
-> pmPhysicalEntity

Regards, Benoit (as a contributor)
> That's just my view. Certainly, there are more ways of
> entity identification. I look forward to discussing them.
>
> Thanks,
>
>      Juergen
>
>
> On 26.10.10 11:44  "Benoit Claise"<[e-mail]>  wrote:
>
>> Hi Juergen,
>>
>> Thanks for the clarification.
>>
>> Something key is to agree on the Power Monitor index for all MIB
>> modules, which IMHO should be part of the Energy-aware Networks and
>> Devices MIB module, but reuse in the other MIB modules.
>>
>> Regards, Benoit.
>>> Hi Benoit,
>>>
>>> Thanks for checking all drafts.
>>>
>>> I don't think that draft-quittek-power-mib-02 makes significant
>>> contributions to the Energy-aware Networks and Devices MIB.
>>> It just covers the Power and Energy Monitoring MIB and the Battery MIB.
>>>
>>> Thanks,
>>>       Juergen
>>>
>>>
>>> On 26.10.10 08:22  "Benoit Claise"<[e-mail]>   wrote:
>>>
>>>> Dear all,
>>>>
>>>> I went through the exercise of mapping the existing six chartered items
>>>> with the existing draft content.
>>>>
>>>> _Energy Management Requirements_
>>>> http://tools.ietf.org/html/draft-quittek-power-monitoring-requirements-02
>>>> https://datatracker.ietf.org/doc/draft-norwin-energy-consider/
>>>> _
>>>> Energy Management Framework_
>>>> http://tools.ietf.org/html/draft-claise-power-management-arch-02
>>>>
>>>> _Energy-aware Networks and Devices MIB_
>>>> http://tools.ietf.org/html/draft-parello-eman-energy-aware-mib-00
>>>> http://tools.ietf.org/html/draft-quittek-power-mib-02
>>>>
>>>> _Power and Energy Monitoring MIB_
>>>> http://tools.ietf.org/html/draft-claise-energy-monitoring-mib-06
>>>> http://tools.ietf.org/html/draft-quittek-power-mib-02
>>>>
>>>> _Battery MIB_
>>>> http://tools.ietf.org/html/draft-quittek-power-mib-02
>>>>
>>>> _Energy Management Applicability_
>>>> http://datatracker.ietf.org/doc/draft-tychon-eman-applicability-statement/
>>>>
>>>> Please let me know if I made any mistakes or if I missed any draft?
>>>>
>>>> Regards, Benoit.
>>>> _______________________________________________
>>>> eman mailing list
>>>> [e-mail]
>>>> https://www.ietf.org/mailman/listinfo/eman