Re: Proposal for VSCP schema

["g8kmh" <g8kmh@xxxxxxxxxxx>]

As one of the potential abusers :-)

Either of the two UID address forms is fine with me, although the
longer form would seem to have some long term advantages and there is
little difference in processing overhead or packet size.

Lehane


--- In xAP_developer@xxxxxxx, Kevin Hawkins <lists@u...>
wrote:
> Mark Harrison (Groups) wrote:
>
> >On Mon, 2005-08-08 at 08:14 -0400, Gregg Liming wrote:
> >
> >
> >>This limitation is (IMO) very limiting to those of us creating
xAP
> >>gateways for systems that have many more than 254 devices and
> >>inevitably
> >>causes "hacks" to be required to handle the
mappings.  I'm
personally
> >>hoping that the xAP spec will be revised soon to support a
much
larger
> >>number of subaddresses.  In the mean time, I've had to resort
to
> >>"virtual" subaddresses that nominally map to
semi-natural
groupings of
> >>devices.  Even this technique, however, doesn't scale well and
will
> >>break if pushed.
> >>
> >>
> >
> >We discussed this at xAPCon04, and ISTR that everyone was in
favour of
> >extending the size of UID.
> >
> >I note that Kevin is going to push this forward, though for the
record,
> >my preference is for 2N8A8S
> >
> >
>
> and mine....  :-)      although I sort of like including the
delimiters
> - but no-one else did so I'll surrender !
>
> >That having been said, I'm in favour of the "majority
decision" on
which
> >length they should be because a quick decision is more important
to me
> >than the difference between 2N8A8S and 2N6A6S - either is enough
for the
> >immediate requirements.
> >
> >If nothing else, it would make the BSC handling in xAPHomeVision
_much_
> >easier - at the moment, we map each house code on to a different
xAP
> >Device, to allow the full 256 X-10 devices - the 254 limit was
terribly
> >annoying. (I realise that xAPHomeSeer has a different set of
> >constraints, because of the way that HomeSeer allows virtual X-10
> >devices.)
> >
> >If truth be told, the BSC Support in xAPHomeVision is good, but
the X-10
> >Schema support is fairly flakey. I'd be in favour of getting the
UID
> >issue resolved ASAP, so we can rewrite the X-10 stuff cleanly!
> >
> >One key question though - will extended UID be enough to push v=12
up to
> >v=13? I think, realistically, yes, in which case we may want to
consider
> >message fragmentation at the same time - though the "get it
done"
rule
> >is again more important to me.
> >
> >
> I think I would like to formally agree the format of the new UID
and
> release it asap so that people can use it from effectively xAP 1.21
> onwards.  I would very much like to get the message sequencing
ironed
> out (and those couple of other things that build on this that we
> discussed at xAPCon) but I think there's still a bit of work to do
here
> and I wouldn't want to delay the UID adoption as it's impacting
lots of
> applications and even causing 'abuse' of the UID as there isn't an
> alternative.  AFAIK the UID change is the only aspect that could
cause
> incompatability with existing applications - the other changes are
all
> really enhancements that work as higher level policies and so
should be
> transparent.  (remember "gracefully ignore any unexpected
parameters you
> don't recognise/expect whilst parsing", including within the
header).
> BTW Gracefully means "don't throw a wobbly" and don't drop
subseqent
> parsing.
>
> >M.
> >
> >
> >
> K