High Level Policy mechanisms

[Kevin Hawkins]

A lot of the policy issues seem to have languished around with no progress
of recent date. A couple are important to allow support for xAP by general
HA controlling applications or hardware so in an attempt to move forward I
intend to propose a pilot usage of the Status mechanism & reponses.
This is
the basic state information returned by a device and also a standard way of
enquiring of such state (rather than waiting for it to arrive). In the
absence of any strong views I'll post a summary of the ideas from this
group
so far. The sequencing issue too needs moving forward.

I have been looking at JamesT's excellent applications just recently
and I note the difficulties that xAP datagram length imposes when a large
amount of information may need to be returned in a xAP message. A good
example is the traffic or news application. We need to suggest a standard
way that this will be presented as the need is apparent. Apart from the
obvious mechanisms of truncation or logical division of the content over
several bodies/messages I think we need to be able to link related messages
perhaps in a sort of 'message 3 of 6' or 'message 3 tbc' with a 'message
end' type scenario. This perhaps also integrating with the concept of
sequencing and ACK/NAK of messages such that integrity checks can be made.
I
have hit this too with returning the status of 256 C-Bus loads.

As a way of moving this forward see my next posting on experimental
TestXX header name/value pair usage.

Kevin