Re: [netmod] AD review of draft-ietf-netmod-entity-06

Hi Martin,

We had a discussion on this and we have some concerns about below statement (behavior in the description statement):

>    This leaf can be configured.  The configured value is used only if
>    the server cannot determine the vendor-specific serial number from
>    the component itself.

For the above sentence “server cannot determine” we have 2 cases:
1.	It can’t be determined because there is nothing detected.  According to the NMDA-draft it is clear that in this case there is no row for the associated component and hence no data.  I think this case is covered by the sentence in the latest draft-ietf-netmod-entity for the list “component” where it is stated: “When the server detects a new hardware component, it initializes a list entry in the operational state.”, so the above sentence only applies for the second case below.
2.	The second case is that something is detected but it can’t be read.  We do not see a reason to use the value configured for the leafs ‘serial-num’, ‘mfg-name’ and ‘model-name’ of a matching entry in the configuration data.  These leafs are defined as optional so why would we report something entered by an operator in the operational datastore that intends to report on what is detected?  Is it not better to not report them at all?  In an NMDA context it would be possible to have a different value (or no value at all) for certain leafs while there is something in the running/intended datastore.

Best regards, Bart

-----Original Message-----
From: netmod [mailto:netmod-bounces@ietf.org] On Behalf Of Robert Wilton
Sent: Thursday, December 21, 2017 4:14 PM
To: Martin Bjorklund <mbj@tail-f.com>; netmod@ietf.org
Subject: Re: [netmod] AD review of draft-ietf-netmod-entity-06

Hi Martin,

On 21/12/2017 11:37, Martin Bjorklund wrote:
> Hi,
>
> I need WG input on this issue.  The question is how to handle 
> 'serial-num', 'mfg-name', and 'model-name'.  I think they should all 
> be treated the same.  Based on previous WG discussion (see e.g. the 
> mail thread "draft-ietf-netmod-entity issue #13"), I think they should 
> all be configurable, but the configured value is only used in 
> operational state if the system cannot read it from the hardware.
I think that this approach is probably OK:
  - The client can always see the real value if it is available.
  - If it is not available then they can assign a value via configuration.

I was also considering an alternative approach of having a separate set of config false leaves for the "burnt in values".  And then having the configurable leaves always override the default operational values. E.g. similar to how an interface MAC address would expect to be handled.

But one set of leaves is probably sufficient.

Thanks,
Rob

>
> So I suggest the following changes:
>
> OLD:
>
>        leaf serial-num {
>          type string;
>          config false;
>          description
>            "The vendor-specific serial number string for the
>             component.  The preferred value is the serial number
>             string actually printed on the component itself (if
>             present).";
>          reference "RFC 6933: entPhysicalSerialNum";
>        }
>
> NEW:
>
>        leaf serial-num {
>          type string;
>          description
>            "The vendor-specific serial number string for the
>             component.  The preferred value is the serial number
>             string actually printed on the component itself (if
>             present).
>
>             This leaf can be configured.  There are two use cases for
>             this; as a 'post-it' note if the server cannot determine
>             this value from the component, or when pre-provisioning a
>             component.
>
>             If the server can determine the serial number from the
>             component, then that value is always used in operational
>             state, even if another value has been configured.";
>          reference "RFC 6933: entPhysicalSerialNum";
>        }
>
> And corresponding text for 'mfg-name' and 'model-name'.
>
> And also:
>
> OLD:
>
>           When the server detects a new hardware component, it
>           initializes a list entry in the operational state.
>
>           If the server does not support configuration of hardware
>           components, list entries in the operational state are
>           initialized with values for all nodes as detected by the
>           implementation.
>
>           Otherwise, the following procedure is followed:
>
>             1. If there is an entry in the /hardware/component list in
>                the intended configuration with values for the nodes
>                'class', 'parent', 'parent-rel-pos' that are equal to
>                the detected values, then:
>
>             1a. If the configured entry has a value for 'mfg-name'
>                 that is equal to the detected value, or if the
>                 'mfg-name' value cannot be detected, then the list
>                 entry in the operational state is initialized with the
>                 configured values for all configured nodes, including
>                 the 'name'.
>
>                 Otherwise, the list entry in the operational state is
>                 initialized with values for all nodes as detected by
>                 the implementation.  The implementation may raise an
>                 alarm that informs about the 'mfg-name' mismatch
>                 condition.  How this is done is outside the scope of
>                 this document.
>
>             1b. Otherwise (i.e., there is no matching configuration
>                 entry), the list entry in the operational state is
>                 initialized with values for all nodes as detected by
>                 the implementation.
>
>           If the /hardware/component list in the intended
>           configuration is modified, then the system MUST behave as if
>           it re-initializes itself, and follow the procedure in (1).";
>
> NEW:
>
>           When the server detects a new hardware component, it
>           initializes a list entry in the operational state.
>
>           If the server does not support configuration of hardware
>           components, list entries in the operational state are
>           initialized with values for all nodes as detected by the
>           implementation.
>
>           Otherwise, the following procedure is followed:
>
>             1. If there is an entry in the /hardware/component list in
>                the intended configuration with values for the nodes
>                'class', 'parent', 'parent-rel-pos' that are equal to
>                the detected values, then the list entry in operational
>                state is initialized with the configured values,
>                including the 'name'.  The leafs 'serial-num',
>                'mfg-name', and 'model-name' are treated specially; see
>                their descriptions for details.
>
>             2. Otherwise (i.e., there is no matching configuration
>                entry), the list entry in the operational state is
>                initialized with values for all nodes as detected by
>                the implementation.
>
>           If the /hardware/component list in the intended
>           configuration is modified, then the system MUST behave as if
>           it re-initializes itself, and follow the procedure in (1).";
>
>
>
> /martin
>
>
>
>
> Benoit Claise <bclaise@cisco.com> wrote:
>> On 12/20/2017 4:00 PM, Martin Bjorklund wrote:
>>> Benoit Claise <bclaise@cisco.com> wrote:
>>>> Hi Martin,
>>>>
>>>> Thanks.
>>>> Only kept the relevant excerpts.
>>>>>> - Some objects are read-write in RFC6933:
>>>>>>          entPhysicalSerialNum
>>>>>>          entPhysicalAlias
>>>>>>          entPhysicalAssetID
>>>>>>          entPhysicalUris
>>>>>>
>>>>>> For example, entPhysicalSerialNum being read-write always bothered me.
>>>>>> serial-num is now "config false", which is a good news IMO.
>>>>> Actually, this was not the intention.  In 
>>>>> draft-ietf-netmod-entity-03 this is configurable.  I missed this in the conversion to NMDA.
>>>> Ah. So no good news in this case...
>>>>>> In the reverse direction, entPhysicalMfgName is read-only in 
>>>>>> RFC6933, while it's "config true" in draft-ietf-netmod-entity
>>>>> Yes, this was added per request from the WG.  See e.g. the thread 
>>>>> "draft-ietf-netmod-entity issue #13".
>>>> Sure. It was mainly an observation.
>>>>> However, I think that what we have now is probably not correct.  I 
>>>>> think that all nodes 'serial-num', 'mfg-name', and 'model-name' 
>>>>> should be config true, and the description of list 'component' 
>>>>> updated to reflect that all these tree leafs are handled the same way.
>>>>>
>>>>> I would like to know what the WG thinks about this.
>>>> Talking as a contributor this time.
>>>> It seems that inventory management is kind of broken when someone 
>>>> can change 'serial-num', 'mfg-name', and 'model-name.
>>> They can't really change them.  The configured values are only used 
>>> (i.e. visible in the operational state) if the device cannot detect 
>>> them automatically.  I.e., they work as "post-it" notes only.
>> If I look at, for example, the mfg-name, description, this is not 
>> what it says.
>>
>>     leaf mfg-name {
>>             type string;
>>             description
>>               "The name of the manufacturer of this physical component.
>>                The preferred value is the manufacturer name string
>>                actually printed on the component itself (if present).
>>
>>                Note that comparisons between instances of the model-name,
>>                firmware-rev, software-rev, and the serial-num nodes are
>>                only meaningful amongst component with the same value of
>>                mfg-name.
>>
>>                If the manufacturer name string associated with the
>>                physical component is unknown to the server, then this
>>                node is not instantiated.";
>>             reference "RFC 6933 <https://tools.ietf.org/html/rfc6933>:
>>             entPhysicalMfgName";
>>
>> Regards, Benoit
>>
>>>
>>> /martin
>>> .
>>>
> _______________________________________________
> netmod mailing list
> netmod@ietf.org
> https://www.ietf.org/mailman/listinfo/netmod
> .
>

_______________________________________________
netmod mailing list
netmod@ietf.org
https://www.ietf.org/mailman/listinfo/netmod