[IPFIX] Interpretation of sequence number handling

[Rick Hofstede <[e-mail]>]

Dear list,

RFC 7011 defines the following regarding sequence numbers in Message headers (Section 3.1 — Message Header Format): Incremental sequence counter modulo 2^32 of all IPFIX Data Records sent in the current stream from the current Observation Domain by the Exporting Process.

This can however be interpreted in two ways:

(1) Incremental sequence counter modulo 2^32 of all IPFIX Data Records sent in the current stream from the current Observation Domain by the Exporting Process *up to* this Message.
(2) Incremental sequence counter modulo 2^32 of all IPFIX Data Records sent in the current stream from the current Observation Domain by the Exporting Process *up to and including* this Message.

It seems that only Section 10.3.2 — Reliability explains which of the two interpretations is right: In the case of UDP, the IPFIX Sequence Number contains the total number of IPFIX Data Records sent for the Transport Session *prior* to the receipt of this IPFIX Message, modulo 2^32.

In my opinion, it would be good to clarify the use of sequence numbers in Message headers already in the definition of sequence numbers in RFC 7011, namely in Section 3.1.

Best regards,

—
Rick Hofstede