Isn't this the standard database mantra where no entry is different from "0". We should surely be using two different values to identify these distinct concepts. Keith > -----Original Message----- > From: rai-bounces@xxxxxxxx [mailto:rai-bounces@xxxxxxxx] On > Behalf Of Worley, Dale R (Dale) > Sent: Wednesday, December 08, 2010 6:58 PM > To: rai@xxxxxxxx; sipping@xxxxxxxx > Subject: [RAI] draft-ietf-sipping-media-policy-dataset: zero > children of an element > > In a number of places, > draft-ietf-sipping-media-policy-dataset-10 specifies that one > element must have one or more children of a particular type. > In many of these cases, having zero children would have a > well-defined meaning. And in various situations, it is > difficult to define appropriate processing without allowing > zero children. I am proposing that we modify the draft to > admit zero children whenever this has a well-defined meaning. > > The two cases I've identified so far are: > > A <streams> element with zero <stream> children, indicating a > session with no media streams. This is needed to be able to > encode SDP descriptions that contain zero m= lines (which is > permitted by RFC 4566). > > In various situations where a policy is specified, we need a > way to specify that no value of a particular attribute is > allowed. This describes a policy that accepts no media > streams, which can happen if two policies are merged that > have no overlap. Without this change, one would not be able > to express the conjunction of two incompatible policies at all. > > Comments? > > Dale > _______________________________________________ > RAI mailing list > RAI@xxxxxxxx > https://www.ietf.org/mailman/listinfo/rai > _______________________________________________ Sipping mailing list https://www.ietf.org/mailman/listinfo/sipping This list is for NEW development of the application of SIP Use sip-implementors@xxxxxxxxxxxxxxx for questions on current sip Use sip@xxxxxxxx for new developments of core SIP
