--On Monday, June 19, 2017 21:26 +0300 Yoav Nir <ynir.ietf@xxxxxxxxx> wrote: >... > By the Postel principle, the receiver should accept this > chain. In practice I might limit it to a lower number, because > I assume nobody does that. I think it's best for the > specification to say that "MUST support a chain of at least > 7 and MUST NOT send a chain longer than 7", and of course > you'd have to say that profiles may further reduce this > number (for IoT). It seems to me that your example, and some others, suggest that if the principle was being stated today, it would be "be conservative about what you send and liberal about what you accept, but nothing justifies violations of common sense or taking actions that would create risks". If the latter/new part is really needed, we may be in worse trouble than with questions about what the principle really means or even whether Jon was right or wrong. john