Gunter, A very targeted reply:
On 9/18/25 07:10, Gunter Van de Velde via Datatracker wrote:
164 The NULL Authentication Type, defined in this document, can be used 165 to provide a meticulously increasing sequence number for stability 166 measurement. It provides none of the protections desired for 167 authentication and is used only to provide BFD stability services to 168 BFD sessions that otherwise have no authentication in use. GV> similar as some others i got triggered by the word 'meticulously'. Maybe use “strictly increasing” (most operator- and implementer-friendly) or “monotonically increasing” (if you want mathematical precision).
Section 6 in secure sequence numbers describes the required property, which is not what you've pasted above. Since we seem to be regularly coming back to the fact that RFC 5880 wasn't clear enough we should simply draft text covering the property that is acceptable to the IESG and paste it into all three documents.
The required property is that when you transmit the next sequence number, it is +1 the prior one in a circular numbering space. That's it.
The reason it is "meticulous" is because in RFC 5880, non-meticulous modes permitted sequence number re-use as a scaling mechanism.
Strictly and monotonically increasing do not cover the +1 property, only that they always go forward.
For the stability draft, the +1 property is required to detect gaps. See also discussion about out of order delivery in the draft.
-- Jeff
