The phrase 'monotonic increasing' seems to be a Humpty-Dumpty one, used with a different sense within RFC to that which I see defined elsewhere; and this could lead to a reduction in security. Elsewhere - dictionaries, encyclopaedia, text books - I see it defined so that when applied to a sequence of numbers, then each number is not less than its predecessor, so that 1 1 1 1 1 1 1 1 1 1 1 1 2 3 5 8 13 1 2.71828 3.14159 4.18 42 are all monotonic increasing sequences whereas 1 2 3 4 5 6 7 9 8 10 is not. Within RFC, mostly those related to security or network management, the context of its use implies, in addition, one or more of a) each number in the sequence is different (as in number used once) b) each number is an integer c) each number is one greater than its predecessor (as in message sequencing) . Most likely, an implementation that conforms to the rest of the world definition would interwork with one that conforms to the RFC one, but with some loss of security, since numbers that are intended to be used only once could be reused. Q1) Can anyone point me to an authoritative source that endorses the RFC usage? Q2) Even so, since the rest of the world usage seems to be so widely defined, should we change our terminology, eg specifying seqences to be strictly increasing when that is what is needed? Tom Petch _______________________________________________ Ietf@xxxxxxxx https://www1.ietf.org/mailman/listinfo/ietf