Re: Protocol: Ignore SEQUENCE elements...

[John McMeeking <jmcmeek@us.ibm.com>]

I do not like the notion of a blanket statement to ignore unknown values in
an ENUMERATION or CHOICE type.  I don't think that it makes any sense for
any of the existing CHOICE or ENUMERATED types, with the possible exception
of resultCode.

I also have problems with doing this for SET and SEQUENCE.  I am willing to
accept it only because it is easier to make a general statement about how
the server should behave: as if they weren't there.  But even then, it
requires some level of confidence that implementations really do ignore
ignore these extensions (i.e. a test suite that injects such constructs).
And I'm not sure what the ramifications are to a client application for
such a blanket statement.  Presumably the client has to deal with the
possibility that the extensions are not supported.  We handle this in
controls by providing both a method for the client to discover if the
extension (control) is supported, and by including a criticality indicator
in the client request.

Yes,  X.680 does allow for extensible types, but you must explicitly define
them as extensible (using "...") and presumably the type "designer" has
considered the ramifications of making a given type extensible.


John  McMeeking