Re: [Idr] draft-rekhter-rfc4760bis-01

[Jie Dong <[e-mail]>]

> >        " Res. - Reserved (8 bit) field. SHOULD be set to 0 by the sender
> >         and ignored by the receiver.
> > 
> >         Note that not setting the field value to 0 may create issues
> >         for a receiver not ignoring the field. In addition this
> >         definition is problematic if it is ever attempted to redefine
> >         the field."
> >
> > I'm not sure if there is some implementation which can cause issues with
> > this field not setting to zero. But this description makes it impossible
to
> > redefine this field. If there is no such inappropriate implementation, I
> > would recommend not to forbid the redefining of this field.
> 
> Seems to me as though this can be addressed by changing the SHOULD to a
> MUST: "MUST be set to 0 by the sender and MUST be ignored by the
receiver."
 
Agreed. 

> As far as I'm concerned the "note that" paragraph is entirely optional.
In any
> case it's informative, not normative.  For that matter I don't think "this
> definition is problematic if it is ever attempted to redefine the field",
it seems
> to have the same characteristics as any other set of flags.  Since the
paragraph
> seems to be confusing, maybe it should just be removed.

> As usual, the way you would introduce new flags to the field is by
revising the
> spec.  The "MUST be ignored" is what makes this (reasonably) safe.

Agreed, IMO this reserved field could have the same characteristics with
reserved fields in other specifications, so the "note that" paragraph may
just be removed.


Best regards,
Jie