<html>
<head>
<META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=us-ascii">
<meta name=Generator content="Microsoft Word 11 (filtered)">
<style>
<!--
/* Font Definitions */
@font-face
{font-family:"MS Mincho";
panose-1:2 2 6 9 4 2 5 8 3 4;}
@font-face
{font-family:Tahoma;
panose-1:2 11 6 4 3 5 4 4 2 4;}
@font-face
{font-family:"\@MS Mincho";
panose-1:2 2 6 9 4 2 5 8 3 4;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0in;
margin-bottom:.0001pt;
font-size:12.0pt;
font-family:"Times New Roman";
color:black;}
a:link, span.MsoHyperlink
{color:blue;
text-decoration:underline;}
a:visited, span.MsoHyperlinkFollowed
{color:purple;
text-decoration:underline;}
pre
{margin:0in;
margin-bottom:.0001pt;
font-size:10.0pt;
font-family:"Courier New";
color:black;}
p.StyleParagraph4Kernat14pt, li.StyleParagraph4Kernat14pt, div.StyleParagraph4Kernat14pt
{margin-top:12.0pt;
margin-right:0in;
margin-bottom:0in;
margin-left:0in;
margin-bottom:.0001pt;
text-align:justify;
line-height:14.0pt;
font-size:12.0pt;
font-family:"Times New Roman";
color:black;}
p.styleparagraph4kernat14pt0, li.styleparagraph4kernat14pt0, div.styleparagraph4kernat14pt0
{margin-top:12.0pt;
margin-right:0in;
margin-bottom:0in;
margin-left:0in;
margin-bottom:.0001pt;
text-align:justify;
line-height:14.0pt;
font-size:12.0pt;
font-family:"Times New Roman";
color:black;}
span.emailstyle18
{font-family:Arial;
color:windowtext;}
span.EmailStyle21
{font-family:Arial;
color:navy;}
@page Section1
{size:8.5in 11.0in;
margin:1.0in 1.25in 1.0in 1.25in;}
div.Section1
{page:Section1;}
/* List Definitions */
ol
{margin-bottom:0in;}
ul
{margin-bottom:0in;}
-->
</style>
</head>
<body bgcolor=white lang=EN-US link=blue vlink=purple>
<div class=Section1>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Thanks guys. Not having been around from
the beginning, I just wanted to make sure that the idea had been considered. Clearly
it has, and there are good reasons for the way things are.</span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'> </span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Thanks,</span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Tim</span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'> </span></font></p>
<div>
<div class=MsoNormal align=center style='text-align:center'><font size=3
color=black face="Times New Roman"><span style='font-size:12.0pt;color:windowtext'>
<hr size=2 width="100%" align=center tabindex=-1>
</span></font></div>
<p class=MsoNormal><b><font size=2 color=black face=Tahoma><span
style='font-size:10.0pt;font-family:Tahoma;color:windowtext;font-weight:bold'>From:</span></font></b><font
size=2 color=black face=Tahoma><span style='font-size:10.0pt;font-family:Tahoma;
color:windowtext'> sis-ams-bounces@mailman.ccsds.org
[mailto:sis-ams-bounces@mailman.ccsds.org] <b><span style='font-weight:bold'>On
Behalf Of </span></b>Scott Burleigh<br>
<b><span style='font-weight:bold'>Sent:</span></b> Wednesday, September 10,
2008 9:08 PM<br>
<b><span style='font-weight:bold'>To:</span></b> sis-ams@mailman.ccsds.org<br>
<b><span style='font-weight:bold'>Subject:</span></b> Re: [Sis-ams] better
subject-matching?</span></font></p>
</div>
<p class=MsoNormal><font size=3 color=black face="Times New Roman"><span
style='font-size:12.0pt'> </span></font></p>
<p class=MsoNormal><font size=3 color=black face="Times New Roman"><span
style='font-size:12.0pt'>Edell, David J. wrote: </span></font></p>
<p class=MsoNormal><font size=2 color=blue face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:blue'>Tim,</span></font></p>
<p class=MsoNormal><font size=3 color=black face="Times New Roman"><span
style='font-size:12.0pt'> </span></font></p>
<p class=MsoNormal><font size=2 color=blue face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:blue'>Advanced filtering options could have
potential usage, and if I remember correctly are available to some degree in
the software bus of Goddard's cFE. I don't think its worth the added
processing costs to change to a string-based subject ID to accomplish that
though. </span></font></p>
<p class=MsoNormal><font size=3 color=black face="Times New Roman"><span
style='font-size:12.0pt'> </span></font></p>
<p class=MsoNormal><font size=2 color=blue face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:blue'>At a minimum, there's always the
possibility of psuedo-filtering by specifying ranges of subject-IDs for
specific categories, which is sometimes done on its own to organize ID
listings. This becomes an implementation choice within a program though,
rather than a specification. </span></font></p>
<p class=MsoNormal><font size=3 color=black face="Times New Roman"><span
style='font-size:12.0pt'> </span></font></p>
<p class=MsoNormal><font size=2 color=blue face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:blue'>I think the SubjectID, UnitID, RoleID
field combination is intended to give a similar effect in combination with the
"all subject" and "all role" subscription types. It's
been a while since I've looked at these field definitions though, so I could be
wrong. This might be another topic for discussion at Berlin.</span></font></p>
<p class=MsoNormal><font size=3 color=black face="Times New Roman"><span
style='font-size:12.0pt'>You're right, David, that's exactly what the
"domain" concept in subscriptions, announcements, etc. is all about.<br>
<br>
The problem here is that AMS is really intended to be for very high performance
(or, alternatively, for acceptable performance on highly constrained hardware)
in messaging, and string matching functions just take a whole lot more
processing time than integer comparison functions; also, strings are typically
a lot bigger than integers, so they consume a lot more bandwidth -- not
necessarily a big deal in Earth orbiters, but a fairly big deal in deep space
operations. So the design decision to use numeric subject IDs rather than
strings was deliberate.<br>
<br>
At the same time, the question of supporting more powerful subject matching
capability does come up over and over again; most (maybe all) commercial
message-oriented middleware systems have it. The approach we've been
taking is to say that where these capabilities are needed you presumably don't
need high efficiency at the same time, so you can afford an extra transmission
hop, in which case the AMS Proxy Architecture (section 6.1 of the spec) is the
most flexible and powerful way to provide this functionality. I believe
CNES, in fact, is already contemplating development of a prototype AMQP-based
AMS Proxy system.<br>
<br>
Scott<br>
<br>
</span></font></p>
<div class=MsoNormal align=center style='text-align:center'><font size=3
color=black face="Times New Roman"><span style='font-size:12.0pt'>
<hr size=2 width="100%" align=center tabindex=-1>
</span></font></div>
<p class=MsoNormal style='margin-bottom:12.0pt'><b><font size=2 color=black
face=Tahoma><span style='font-size:10.0pt;font-family:Tahoma;font-weight:bold'>From:</span></font></b><font
size=2 face=Tahoma><span style='font-size:10.0pt;font-family:Tahoma'> <a
href="mailto:sis-ams-bounces@mailman.ccsds.org">sis-ams-bounces@mailman.ccsds.org</a>
[<a href="mailto:sis-ams-bounces@mailman.ccsds.org">mailto:sis-ams-bounces@mailman.ccsds.org</a>]
<b><span style='font-weight:bold'>On Behalf Of </span></b>Ray, Timothy J.
(GSFC-583.0)<br>
<b><span style='font-weight:bold'>Sent:</span></b> Wednesday, September 10,
2008 6:15 PM<br>
<b><span style='font-weight:bold'>To:</span></b> <a
href="mailto:sis-ams@mailman.ccsds.org">sis-ams@mailman.ccsds.org</a><br>
<b><span style='font-weight:bold'>Subject:</span></b> [Sis-ams] better
subject-matching?</span></font></p>
<p class=MsoNormal><font size=2 color=black face=Arial><span style='font-size:
10.0pt;font-family:Arial'>Hello all,</span></font></p>
<p class=MsoNormal><font size=3 color=black face="Times New Roman"><span
style='font-size:12.0pt'> </span></font></p>
<p class=MsoNormal><font size=2 color=black face=Arial><span style='font-size:
10.0pt;font-family:Arial'>Does anyone see a (worthwhile) benefit to enhancing
our subject-matching capabilities to allow hierarchical subject-ids and some
pattern-matching? Subjects would be transmitted as character strings
rather than 2-byte numbers, and subscribers would be able to specify some sort
of regular-expression format.</span></font></p>
<p class=MsoNormal><font size=3 color=black face="Times New Roman"><span
style='font-size:12.0pt'> </span></font></p>
<p class=MsoNormal><font size=2 color=black face=Arial><span style='font-size:
10.0pt;font-family:Arial'>For example, if there were these subjects:</span></font></p>
<p class=MsoNormal><font size=2 color=black face=Arial><span style='font-size:
10.0pt;font-family:Arial'>
Attitude.sun_sensor</span></font></p>
<p class=MsoNormal><font size=2 color=black face=Arial><span style='font-size:
10.0pt;font-family:Arial'>
Attitude.momentum_wheel</span></font></p>
<p class=MsoNormal><font size=2 color=black face=Arial><span style='font-size:
10.0pt;font-family:Arial'>
Attitude.gyros</span></font></p>
<p class=MsoNormal><font size=3 color=black face="Times New Roman"><span
style='font-size:12.0pt'> </span></font></p>
<p class=MsoNormal><font size=2 color=black face=Arial><span style='font-size:
10.0pt;font-family:Arial'>Then an application might subscribe to
attitude.* to receive all subjects within the
‘attitude’ domain.</span></font></p>
<p class=MsoNormal><font size=3 color=black face="Times New Roman"><span
style='font-size:12.0pt'> </span></font></p>
<p class=MsoNormal><font size=2 color=black face=Arial><span style='font-size:
10.0pt;font-family:Arial'>I don’t think this enhancement is needed for
the typical NASA/Goddard mission, nor are any missions (that I’m aware
of) asking for it. Still, it seems like something worth
considering. Does anyone have an opinion?</span></font></p>
<p class=MsoNormal><font size=3 color=black face="Times New Roman"><span
style='font-size:12.0pt'> </span></font></p>
<p class=MsoNormal><font size=2 color=black face=Arial><span style='font-size:
10.0pt;font-family:Arial'>Tim</span></font></p>
<p class=MsoNormal><font size=3 color=black face="Times New Roman"><span
style='font-size:12.0pt'> </span></font></p>
<pre wrap=""><font size=2 color=black face="Courier New"><span
style='font-size:10.0pt'> </span></font></pre><pre style='text-align:center'><font
size=2 color=black face="Courier New"><span style='font-size:10.0pt'>
<hr size=4 width="90%" align=center>
</span></font></pre><pre><font size=2 color=black face="Courier New"><span
style='font-size:10.0pt'> </span></font></pre><pre><font size=2
color=black face="Courier New"><span style='font-size:10.0pt'>_______________________________________________</span></font></pre><pre><font
size=2 color=black face="Courier New"><span style='font-size:10.0pt'>Sis-ams mailing list</span></font></pre><pre><font
size=2 color=black face="Courier New"><span style='font-size:10.0pt'><a
href="mailto:Sis-ams@mailman.ccsds.org">Sis-ams@mailman.ccsds.org</a></span></font></pre><pre><font
size=2 color=black face="Courier New"><span style='font-size:10.0pt'><a
href="http://mailman.ccsds.org/cgi-bin/mailman/listinfo/sis-ams">http://mailman.ccsds.org/cgi-bin/mailman/listinfo/sis-ams</a></span></font></pre><pre><font
size=2 color=black face="Courier New"><span style='font-size:10.0pt'> </span></font></pre>
<p class=MsoNormal><font size=3 color=black face="Times New Roman"><span
style='font-size:12.0pt'> </span></font></p>
</div>
</body>
</html>