Providing policy around messages (was Re: Feedback from UHKA 2003)

[Kevin Hawkins]

I want to try and agree on some of the policies that we need on top
of the lower level xAP message protocol that will allow easy incorporation
of a device type model for a xAPp within a hardware or software controller
type device. This will facilitate software and hardware developers wishing
to support xAP to proceed easily with a base implementation that will work
internally with their state models. ( Harmony, Autom8it, HomeBrain, Ace,
Homeseer etc). It will also allow a much easier xAP connector to be written
for HomeVision.

There are a number of things that come from this that we need to
discuss and I think it's best if we divide the areas into their own
separate
threads and then thrash them through here on the xAP developer list.

Here are some of the topics. There are no doubt a few more - could
you comment on this and then I shall start threads on each of the topics we
agree.

Topic 1: A base level 'Status' schema that provides for minimalist
essential state reporting for the typical devices that are prevalent today
in the HA world. ON OFF LEVEL etc

Topic 2: Discussion around inheritance of classes - for example if
the above Class was defined as XAPSTATUS then should xAPStatus.C-Bus
inherit
from xAPSTATUS and further should xAPStatus.C-Bus.Lighting enforce the
inheritance from the C-Bus class.

Topic 3: The importation of Class/Schema templates into xAP and their
repository. Includes XSLT XML ideas.

Topic 4: The point to point acknowledgement policy that we need to
provide to ensure delivery / reception of xAP critical data - this
discussion to incorporate sequencing.

Topic 5: Suggestion that all devices must support targeting within
the spec (change from optional to mandatory)


I think all these issues are related and need to have concurrent discussion
- there are also the following pending topics from earlier discussion that
we need to address so I have listed them here for completeness - some of
them have are entwined with the above.

TOPIC: Targetting based on UID. Contentious I know.

TOPIC: Wildcarding of UID

TOPIC: Event based addressing (Patrick)

TOPIC: Discovery and Configuration

TOPIC: Groups and Scenes

I also note that we have a large number of members (58) of the
general xAP list (which is very quiet)and (19) on this list - whilst I
don't
want to create an unmanageable free for all there are some people there
that
have valued opinions. Either we should solicit their input or announce our
intentions on that list.I assume this list is restricted to members who are
actively developing xAP applications.

Kevin