During the last IETF meeting, we discussed the PSAMP issue 12.
PROTO-12 Discuss how to implement the observation point report interpretation (if we need one)The "Associations Report Interpretation" in http://www.ietf.org/internet-drafts/draft-ietf-psamp-protocol-03.txt, which BTW has been renamed to "Select Path Report Interpretation", currently contains the observationPointId information element, amongst others:
Scope: selectionPath Non-Scope: observationPointId selectorId (one or more) Note that the section also specifies: The observationPointID SHOULD be first Information Element and the optional processes SHOULD be last ones so that the path of the selected Packet is provided in the logical order. [PSAMP-INFO] currently specifies:
6.2.19 observationPointIdThe issue is that a mapping between the observationPointId and the existing information element(s) such as interfaceId, lineCardId, or routerId is required, adding some complexity in PSAMP, as yet another option template is required.
The proposal is that:
1. we don't define the observationPointId in [PSAMP-INFO], but we use the any information element (such as interfaceId, lineCardId, or routerId) to define the observation point
2. as the "Select Path Report Interpretation" is composed only of one observation point and selector Id(s), we simply assume that the non-selector ID(s) is the observation point. This way, we avoid the sentence "The observationPointID SHOULD be first Information Element and the optional processes SHOULD be last ones ." that impose a new rule in IPFIX: the meaning of a specific I.E. depends on the order of the I.E. in the record
3. If a more complex observation point is required such as an unique ID representing a list of interfaces, a new Information Element is defined and can be used right away.
Note: an alternate solution would be to have 2 scopes in the "Select Path Report Interpretation": the selectionPath, and the observation point. However, this was not considered as a clean solution.
Here is the text proposal
Selection Path Report Interpretation