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RE: FW: xAP configuration protocol
- Subject: RE: FW: xAP configuration protocol
- From: Ian B
- Date: Tue, 12 Aug 2003 22:10:00 +0000
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<DIV><FONT face="Arial" size="2">the only
discussion that hinders us to do something like this are the only-senders,
because these devices would have to support a device.ping message, right?
for this I have a few questions anyway. it is right that these xAP only
sender devices are most likely RS232 devices? I assume that an Ethernet
device would be enough powerful to support to receive messages. also for
RS485 devices, I assume they have to have some kind of collision detection
on the network, to figure out if it can send a message or if someone else
is sending (standard multimaster problems on RS485 networks). if there are
only RS232 devices, how are they managed. there has to be a gateway that
connects the RS232 device to another network since RS232 is only PtP. if
this is the case then maybe the gateway has to be able to support a PING
command of its dumb RS232 device.<FONT face="Times New Roman"
size="3"> </FONT></FONT></DIV>
<DIV><FONT face="Arial" color="#0000ff"
size="2"></FONT> </DIV>
<DIV><SPAN class="488115919-12082003"><FONT
face="Arial" color="#0000ff" size="2">A
couple of points here:</FONT></SPAN></DIV>
<DIV><SPAN class="488115919-12082003"><FONT
face="Arial" color="#0000ff"
size="2">There are quite a few of us now with embedded devices
around the house. A lot of these are the likes of 2k PIC processors and
other slightly more powerful devices. A typical upper limit is 8k for these
low power devices. Irrespective of the network 232/485/422 code space is at
a premium. Adding something like ping and subsequently the ability to
rename its UID could be the difference between the code fitting and having
to redesign with a larger chip if it is
available.</FONT></SPAN></DIV>
<DIV><SPAN class="488115919-12082003"><FONT
face="Arial" color="#0000ff"
size="2"></FONT></SPAN> </DIV>
<DIV><SPAN class="488115919-12082003"><FONT
face="Arial" color="#0000ff" size="2">The
Rabbit chips and larger Atmel AVR range are generally more generous in the
flash stakes ranging from 8k to 128k for the devices I
use.</FONT></SPAN></DIV>
<DIV><SPAN class="488115919-12082003"><FONT
face="Arial" color="#0000ff"
size="2"></FONT></SPAN> </DIV>
<DIV><SPAN class="488115919-12082003"><FONT
face="Arial" color="#0000ff" size="2">I am
currently working on a device which will Ethernet enable even the little 2k
PIC devices and hopefully for only around 50 quid or so, we shall see.
Anyway, this will work as a web server and an RS232 pass through. This
means that your basic code space limited 232 based 2k PIC will suddenly
become Ethernet enabled. The user would not have access to the Ethernet
code space other than for Web pages. The only tricky problem I have at the
moment is stripping off the <STX> and <ETX> bits. Jury is out
on this one at the moment. It may well be I leave this to the owner of the
unit as at this early stage the developer is likely to still be in the
picture.</FONT></SPAN></DIV>
<DIV><SPAN class="488115919-12082003"><FONT
face="Arial" color="#0000ff"
size="2"></FONT></SPAN> </DIV>
<DIV><SPAN class="488115919-12082003"><FONT
face="Arial" color="#0000ff"
size="2">Personally I think Ethernet enabled low cost devices
will proliferate in the home of the future. I know my wife won't tolerate
anything that makes any noise or can be seen unless absolutely necessary.
She is not alone either for most of
us!!</FONT></SPAN></DIV>
<DIV><SPAN class="488115919-12082003"><FONT
face="Arial" color="#0000ff"
size="2"></FONT></SPAN> </DIV>
<DIV><SPAN class="488115919-12082003"><FONT
face="Arial" color="#0000ff"
size="2">Let's not dismiss these 232 based devices too quickly
when thinking this topic through.</FONT></SPAN></DIV>
<DIV><SPAN class="488115919-12082003"><FONT
face="Arial" color="#0000ff"
size="2"></FONT></SPAN> </DIV>
<DIV><SPAN class="488115919-12082003"><FONT
face="Arial" color="#0000ff"
size="2">Ian</FONT></SPAN></DIV>
<DIV><FONT face="Arial" color="#0000ff"
size="2"></FONT> </DIV>
<BLOCKQUOTE>
<DIV class="OutlookMessageHeader" dir="ltr"
align="left"><FONT face="Tahoma"
size="2">-----Original Message-----<B>From:</B>
Silvan Sauter [mailto:silvan@xxxxxxx]<B>Sent:</B>
12 August 2003 19:19<B>To:</B>
xAP_developer@xxxxxxx<B>Subject:</B> Re: FW: [xAP_developer]
xAP configuration protocol</FONT></DIV><FONT
face="sans-serif" size="2">hi all,</FONT>
<FONT face="sans-serif" size="2">it looks like
there is definitely some need for discussions on these configuration
points. i appologize if i'm asking too stupid questions, or if i miss
things that are maybe solved already, but i just got into this xAP
stuff.</FONT> <FONT face="sans-serif"
size="2">i don't think we have to talk about a self
configuring system (a DHCP kind of thing). as kevin is saing, we have to
keep
the level of complexity down and not overload the system. we don't reinvate
IP here. but based on what we know about IP, i think there are a few smart
opportunities. in terms of device address configuration, i'm thinking about
something like autoIP. as mentioned already, a device should have the
opportunity to pick a UID (in a range or a fix one). we mentioned the
problem of having another device with the same address. what if we would
have an xAP PING message, that allows to figure out if a device exists in
the network?</FONT> <FONT face="sans-serif"
size="2">so a setup process could look as
follows:</FONT> <FONT face="sans-serif"
size="2"> 1.
device picks default UID
(manufacturer specific range or something)</FONT> <FONT
face="sans-serif" size="2">
2.
device checks if UID exist in the network (it does a PING to the
address)</FONT> <FONT face="sans-serif"
size="2"> 3.
if yes, device increments its
address and goes to 2.</FONT> <FONT face="sans-serif"
size="2">
if no, device uses
UID</FONT> <FONT face="sans-serif"
size="2"> 4.
devices broadcasts
config.newdevice message</FONT> <FONT face="sans-serif"
size="2">a ping message would in my view look as
follows:</FONT> <FONT face="sans-serif"
size="2">xAP.header</FONT> <FONT
face="sans-serif" size="2">{</FONT> <FONT
face="sans-serif" size=&
quot;2">
...</FONT> <FONT face="sans-serif"
size="2"> target=
uid of the target</FONT> <FONT face="sans-serif"
size="2">
...</FONT> <FONT face="sans-serif"
size="2">}</FONT> <FONT face="sans-serif"
size="2">device.ping</FONT> <FONT
face="sans-serif" size="2">{</FONT> <FONT
face="sans-serif" size="2">
uid=nnddddss</FONT> <FONT
face="sans-serif" size="2"> }</FONT>
<FONT face="sans-serif" size="2">i think the
target=UID in the header does not exist, right? so we would have to do
something that you can target a device by its address.</FONT>
<FONT face="sans-seri
f" size="2">if the device exists in the network it would
answer with it's heartbeat.</FONT> <FONT
face="sans-serif" size="2">the problem we have here
in general are the devices that do not support sending a hb and i think
this is something that would have to be mandatory if the protocol goes into
this direction. as kevin is saying, if a device does not support a hb,
nobody knows that it is there. with the PING command we could actually
force a device to send its hb.</FONT> <FONT
face="sans-serif" size="2">as for the rest of this
autoUID thing we could use standard xAP messages. the device that is new on
the network would send a device.new message and deliver all the parameters
that can be configured with there actual values to the
network.</FONT> <FONT face="sans-serif"
size="2">xAP.header</FONT> <FONT
face="sans-serif" size="2">{</FONT> <FONT
face="s
ans-serif" size="2">
...</FONT> <FONT face="sans-serif"
size="2">}</FONT> <FONT face="sans-serif"
size="2">device.new</FONT> <FONT
face="sans-serif" size="2">{</FONT> <FONT
face="sans-serif" size="2">
uid=nnddddsss</FONT> <FONT
face="sans-serif" size="2">
location=location</FONT> <FONT
face="sans-serif" size="2">
target=vendor.device.instance</FONT> <FONT
face="sans-serif" size="2">
parameter0=xx</FONT> <FONT
face="sans-serif" size="2">
parameter1=yy</FONT> <FONT face="san
s-serif" size="2">}</FONT> <FONT
face="sans-serif" size="2">a configuration
application could now take all these parameters and let the user change
them and send a config.set message back to the device.</FONT>
<FONT face="sans-serif"
size="2">xAP.header</FONT> <FONT
face="sans-serif" size="2">{</FONT> <FONT
face="sans-serif" size="2">
...</FONT> <FONT face="sans-serif"
size="2">}</FONT> <FONT face="sans-serif"
size="2">config.set</FONT> <FONT
face="sans-serif" size="2">{</FONT> <FONT
face="sans-serif" size="2">
uid=newuid</FONT> <FONT
face="sans-serif" size="2">
location=newlocatio
n</FONT> <FONT face="sans-serif"
size="2">
target=newtarget</FONT> <FONT face="sans-serif"
size="2">
parameter0=newparameter0</FONT> <FONT face="sans-serif"
size="2">
paramteter1=newparameter1</FONT> <FONT face="sans-serif"
size="2">}</FONT> <FONT face="sans-serif"
size="2">in addition there would also be a config.get message
that brings back the configuration parameters for a known
device.</FONT> <FONT face="sans-serif"
size="2">the only dicussion that hinders us to do something
like this are the only-senders, because these devices would have to support
a device.ping message, right? for this i have a few questions anyway. it is
right that these xAP only sender devices are most likely RS232 de
vices? i assume that an ethernet device would be enough powerful to support
to receive messages. also for RS485 devices, i assume they have to have
some kind of collision detection on the network, to figure out if it can
send a message or if someone else is sending (standard multimaster problems
on RS485 networks). if there are only RS232 devices, how are they managed.
there has to be a gateway that connects the RS232 device to another network
since RS232 is only PtP. if this is the case then maybe the gateway has to
be able to support a PING command of its dumb RS232 device.</FONT>
<FONT face="sans-serif"
size="2">silvan</FONT>
<TABLE width="100%">
<TBODY>
<TR vAlign="top">
<TD width="40%"><FONT face="sans-serif"
size="1"><B>"Kevin Hawkins"
<lists@xxxxxxx></B> </FONT>
<P><FONT face="sans-serif"
size="1">12.08.2003 13:46</FONT> <TABLE
border="1">
<TBODY>
<TR vAlign="top">
<TD bgColor="white">
<DIV align="center"><FONT face="sans-serif"
size="1">Please respond
toxAP_developer@xxxxxxx</FONT></DIV></TD></TR></TBODY></TABLE></P>
<TD width="59%">
<TABLE width="100%">
<TBODY>
<TR>
<TD>
<DIV align="right"><FONT face="sans-serif"
size="1">To</FONT></DIV>
<TD vAlign="top"><FONT face="sans-serif"
size="1"><xAP_developer@xxxxxxx></FONT> <TR>
<TD>
<DIV align="right"><FONT face="sans-serif"
size="1">cc</FONT></DIV>
<TD vAlign="top">
<TR>
<TD>
<DIV align="right"><FONT face="sans-serif"
size="1">Subject</FONT></DIV>
<TD vAlign="top"><FONT face="sans-serif"
size="1">FW: [xAP_developer] xAP configuration
protocol</FONT></TD></TR></TBODY></TABLE>
<TABLE>
<TBODY>
<TR vAlign="top">
<TD>
<TD></TD></TR></TBODY></TABLE></TD></TR></TBODY></TABLE><FONT
size="3"><TT>Hi Sylvan..
A feisty topic this one ! We had a
lot of discussion a while back (in the original YahooGroup) on exactly this
topic and also an entwined one which is devicediscovery. This is the
ability to plug devices onto a network and otherdevices recognise / learn
of their capabilities. On the configuration
issue there were many different suggestions, ofvarying complexities, and
lots of discussion about network trafficramifications, which becomes very
important on low speed (eg RS232transports). One of the major issues was
that some devices may only bereceivers and not able to chirp up to an 'is
this uid free ?' type messageor indeed be able to ask for a UID. This meant
that we needed to provide alistener that knew about UID's from such devices
based on heartbeats ord
ata. We were not sure if there should be an address management server(along
the lines of DHCP) or whether we should strive to maintain thedecentralised
nature of xAP. There could be issues too with networks thatbecome bridged,
and we anticipated this with the allocation of a networkidentity within the
UID. Also proposed were utilising some unique identitiesin hardware - like
i-buttons, or the pre-allocation of some UID ranges tovendors - sort of
similar to MAC addresses currently using flash RAM etc..
In the end we took the view that while networks were
small andprivate that manual management of UID's was workable and we
thereforepostponed the official mechanism to see how things evolved.
Probably thisstill holds but very soon it is going to become an
issue again. So I wouldwelcome the revival of the discussion and some
proposals - however we need achampion :-) and it is a surprisingly awkward
area, really only becausethere are lots of solutions and you have to trade
features vs complexity.Would you feel like stepping up to the mark on this
one ?? This group wouldform the basis of the discussion.
Additionally a few people, Patrick I think
particularly, are usingsome configuration xAP messages to allow setting of
fundamental xAPconfiguration data (source addresses, heartbeat interval and
UID). We coulddo with formalising the Schemas here so we have some
communality - and thiswould then put in place a layer for higher level
policy that is needed forthe configuration / discovery issues.
I run about a dozen xAPp instances here and the
network sees around100 different UID's ( I use sub addressing for the C-Bus
stuff whichgenerates a unique UID per switched load ). I haven't
experienced anydifficulties with UID - except hubs without one and the
occasionalDEADBEEF's ;-). Indeed having conflicting UID's doesn't break the
network (a design strength) however it makes abbreviated source recognition
, andcache application
s fail - so it shouldn't be allowed.
Kevin > -----Original Message----- >
From: silvan4you [mailto:silvan@xxxxxxx]
> Sent: 12 August 2003 10:32 > To:
xAP_developer@xxxxxxx > Subject: [xAP_developer] xAP
configuration protocol > > has anyone of you
thought about some kind of configuration prototcol > for xAP
devices? i thinking about something that you don't have to >
preconfigure UID etc before you connect a device to the network
> (Ethernet or RS485 or whatever). it would be ideal if a factory
new > device has some kind of standard address (or is is in a
predefined > default address range) and that you could change
the address over a > defined xAP prototcol. >
> i'm also thinking further about a protocol that allows you
to change&nbs
p; > the configuration of an xAP device (not only UID but also
other > parameters). > > has
someone did some work on such definitions already? >
> regards, > silvan >
> > > ------------------------ Yahoo! Groups
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