[IPFIX] IPFIX observationPointId uniqueness

Dear IPFIX experts,

IPFIX observationPointId (#138) is defined as:

          An identifier of an Observation Point that is unique per
          Observation Domain.  It is RECOMMENDED that this identifier is
          also unique per IPFIX Device.  Typically, this Information
          Element is used for limiting the scope of other Information
          Elements.

We now also have observationPointType (#277), defined as:

           Type of observation point. Values assigned to date are:

           1. Physical port
           2. Port channel
           3. Vlan.


Could we relax the uniqueness requirements of observationPointId when an 
observationPointType is also exported, such that the { 
observationPointType, observationPointId } pair must be unique, though 
not the observationPointId itself.

The reason being that observation points of different types already have 
IDs, though these are not unique. eg, we have interface 1, 2, 3, ...; 
vlan 1, 2, 3, ...; port 1, 2, 3, ...

So an extra mediation layer is required to convert values from each of 
these number spaces into unique IDs in the observationPointId number 
space - which becomes harder as we add more places that observations can 
be made, ie more observationPointTypes.

Whereas prefixing with the observationPointType achieves the required 
uniqueness in a faster, simpler, and more reliable way.

To achieve this, I'd propose the following definition change:

          An identifier of an Observation Point that is unique per
          Observation Domain and per observationPointType, if specified.
          It is RECOMMENDED that this identifier is
          also unique per IPFIX Device.  Typically, this Information
          Element is used for limiting the scope of other Information
          Elements.

For backwards compatibility, we could define observationPointType = 0 to 
be "unspecified".

Thanks,
P.

_______________________________________________
IPFIX mailing list
[email protected]
https://www.ietf.org/mailman/listinfo/ipfix