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Fellas,<br>
<br>
Here's my 2 cents......<br>
When I started with the TCONS WG, I didn't know much (actually nil) about
networks nor did I have a great desire to learn the details of all the
protocols. However, as a software systems engineer, I was drawn to
the fact that TCONS was trying to provide a GENERIC INTERFACE to the
underlying busses, which makes my life as an applications developer so
much easier. To me, TCONS abstracted the differences among the
different protocols and busses, and allowed me to write PORTABLE
software. That translates into less risk, cost, and schedule, words
that missions understand. I think Steve's bullet #3 hits the nail
on the head. I've been espousing these points to missions and they
are buying into it. We (software people) are tired of rewriting
software for the same hardware, never mind different hardware, because
everyone wants to do it "their way". IF, like Dai said,
there was someplace to go that standardized this whole mush of stuff,
many would jump on the bandwagon. The SOIS acronym is no longer a
strange one to software people here in my branch that are doing MISSION
work. No one cares about the underlying protocols so much as the
fact that there's a well-defined interface regardless of the underlying
bus.<br>
<br>
Now for the technical 2 cents......we did our Ethernet prototype using
that much beleaguered UDP/IP both for guaranteed and scheduled
service. Of course this prototype didn't have the APIs implemented,
but I don't think it would be a stretch to update. We can/should discuss
the prototype, the resulting data, and the "reliable UDP" in
Athens. My point is that we ran what we functionally thought was a TCONS
architecture using that darned IP protocol, and found it to be quite
straightforward. I expect the same for SpaceWire. <br>
Perhaps we should just say we can't accommodate ALL bus
protocols......and stop wasting 80% of our time on 20% of the
problem. Like TM/TC, is doesn't fit every scenario, but is used for
at least 90% of our data. The other 10% has to be addressed each
mission, but that's a hell of a lot better than rewriting for 50% or more
each mission.<br>
<br>
And so it goes.<br>
Jane<br>
<br>
At 11:42 PM 4/5/2005 +0200, Chris Plummer wrote:<br>
<br>
<blockquote type=cite cite><font face="arial" size=2 color="#000080">Hi
Steve,<br>
</font><br>
<font face="arial" size=2 color="#000080"> <br>
</font><br>
<font face="arial" size=2 color="#000080">The sort of thing we need is
something that will sell TCONS to a project manager. That means that it
needs to be less than three minutes long verbally (including the 2 minute
phone call interruption) and must be no more than 2 A4 pages of printed
matter of which at least one and a half pages should be cartoons and
words should be in 18 point text minimum. The emphasis must be on how
TCONS will make that project managers life more endurable, which means
that there is no real room for technical arguments, and certainly no
scope for a bitching session about TCP/IP. To do that you need to try to
feel the way that project manager feels.<br>
</font><br>
<font face="arial" size=2 color="#000080"> <br>
</font><br>
<font face="arial" size=2 color="#000080">Seriously, CCSDS secretariat
now includes professional PR and marketing support. If we can get TCONS
through next week I think we should start try to get some input from that
function!<br>
</font><br>
<font face="arial" size=2 color="#000080"> <br>
</font><br>
<font face="arial" size=2 color="#000080">Cheers,<br>
</font><br>
<font face="arial" size=2 color="#000080">
Chris.<br>
</font><br>
<font face="arial" size=2 color="#000080"> <br>
<hr>
<div align="center">
</font></div>
<font face="tahoma" size=2><b>From:</b> Steve Parkes
[<a href="mailto:sparkes@computing.dundee.ac.uk" eudora="autourl">mailto:sparkes@computing.dundee.ac.uk</a>]
<br>
<b>Sent:</b> 04 April 2005 18:03<br>
<b>To:</b> Chris Plummer<br>
<b>Cc:</b> 'Patrick.Plancke@esa.int';
'sois-tcons@mailman.ccsds.org'<br>
<b>Subject:</b> SOIS TCONS<br>
</font><br>
<font face="Times New Roman, Times"> <br>
</font><br>
<font face="arial" size=2>Chris,<br>
</font><br>
<font face="arial" size=2> <br>
</font><br>
<font face="arial" size=2>Following on from the last teleconference,
could you let me know what else you need besides the slides that I have
already provide, after your previous request?<br>
</font><br>
<font face="arial" size=2> <br>
</font><br>
<font face="arial" size=2>Some thoughts about USPs for TCONS:<br>
</font><br>
<font face="arial" size=2>-</font><font size=1>
</font><font face="arial" size=2>Provides various traffic classes
appropriate for onboard use<br>
</font><br>
<font face="Courier New, Courier" size=2>o</font><font size=1>
</font><font face="arial" size=2>Best effort with priority<br>
</font><br>
<font face="Courier New, Courier" size=2>o</font><font size=1>
</font><font face="arial" size=2>Guaranteed delivery with priority<br>
</font><br>
<font face="Courier New, Courier" size=2>o</font><font size=1>
</font><font face="arial" size=2>Scheduled delivery (deterministic)<br>
</font><br>
<font face="arial" size=2>-</font><font size=1>
</font><font face="arial" size=2>Can carry other protocols (e.g. TCP/IP)
without upsetting time-critical traffic<br>
</font><br>
<font face="arial" size=2>-</font><font size=1>
</font><font face="arial" size=2>TCONS maintains the following features
which may also be present in other protocols:<br>
</font><br>
<font face="Courier New, Courier" size=2>o</font><font size=1>
</font><font face="arial" size=2>Generic interface to application
software across different underlying buses/networks<br>
</font><br>
<font face="Courier New, Courier" size=2>o</font><font size=1>
</font><font face="arial" size=2>Interoperability<br>
</font><br>
<font face="wingdings" size=2>§</font><font size=1>
</font><font face="arial" size=2>Software interoperability via API
definition<br>
</font><br>
<font face="wingdings" size=2>§</font><font size=1>
</font><font face="arial" size=2>Equipment interoperability via PDU and
protocol definition<br>
</font><br>
<font face="arial" size=2> <br>
</font><br>
<font face="arial" size=2>Regards<br>
</font><br>
<font face="arial" size=2> <br>
</font><br>
<font face="arial" size=2>Steve<br>
</font><br>
<font face="arial" size=2> <br>
</font><br>
<font face="Times New Roman, Times">------------------------------------------<br>
</font><br>
<font face="Times New Roman, Times">Steve Parkes<br>
</font><br>
<font face="Times New Roman, Times">Space Systems Research Group<br>
</font><br>
<font face="Times New Roman, Times">Applied Computing, University of
Dundee<br>
</font><br>
<font face="Times New Roman, Times">Dundee</font>, DD1 4HN, Scotland,
UK<br>
<br>
<font face="Times New Roman, Times">Tel: +44 1382 345194<br>
</font><br>
<font face="Times New Roman, Times">Fax: +44 1382 348838<br>
</font><br>
<font face="Times New Roman, Times">Mobile</font>: +44 784 138 3779<br>
<br>
<font face="Times New Roman, Times"> <br>
</font>_______________________________________________<br>
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