Noel Chiappa wrote:
For me, I would say that unless the implementor in question has
experience in designing protocols, and fairly deep understanding
of that particular area, they are not in a position to make a
good judgement on whether or not they can ignore a 'SHOULD'.
True Noel, but the author has to be aware that he might not get what
it wants. See RFC2119 Section 6.
SHOULD really shines in protocols that are updated. For example:
X1 is in original Protocol v1.0
MUST USE X1
For protocol v2.0, X2 is a improved version of X1.
SHOULD USE X2 IF POSSIBLE, IF NOT
MUST USE X1
Its the same as saying
MUST USE X2 first or X1 as a fallback
Implementors using Protocol v2.0 will use X2, if it wants to because
it can use X1. You have no control over this. X2 can be an improved
version the operator doesn't like. He likes X1.
Legacy Implementors using Protocol v1.0 doesn't known anything about
X2 so it will naturally use X1.
On the only had, you have can have:
Protocol v1.0 with X1 with Protocol V2.0 X1 and X2.
The protocol v2.0 implementor may not be able to do X2 unless it knows
the other side is protocol v2.0 ready.
It all depends - it can have an auto-negotiation for the highest X
version or one that is disabled too.
In all cases, The end points must not break down when one or the other
lacks X2 support.
Make sense?
--
HLS
_______________________________________________
Ietf mailing list
Ietf@xxxxxxxx
https://www.ietf.org/mailman/listinfo/ietf