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<title>Dissemination</title>
<meta name="author" content="Philip Levis and Gilman Tolle" />
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+<div class="document" id="dissemination">
<h1 class="title">Dissemination</h1>
<table class="docinfo" frame="void" rules="none">
<col class="docinfo-name" />
<td>Philip Levis and Gilman Tolle</td></tr>
<tr class="field"><th class="docinfo-name">Draft-Created:</th><td class="field-body">10-Dec-2004</td>
</tr>
-<tr class="field"><th class="docinfo-name">Draft-Version:</th><td class="field-body">1.6</td>
+<tr class="field"><th class="docinfo-name">Draft-Version:</th><td class="field-body">1.7</td>
</tr>
-<tr class="field"><th class="docinfo-name">Draft-Modified:</th><td class="field-body">2006-12-12</td>
+<tr class="field"><th class="docinfo-name">Draft-Modified:</th><td class="field-body">2007-06-14</td>
</tr>
<tr class="field"><th class="docinfo-name">Draft-Discuss:</th><td class="field-body">TinyOS Developer List <tinyos-devel at mail.millennium.berkeley.edu></td>
</tr>
</tbody>
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-<div class="document" id="dissemination">
<div class="note">
<p class="first admonition-title">Note</p>
<p class="last">This memo documents a part of TinyOS for the TinyOS Community, and
of this memo is unlimited. This memo is in full compliance with
TEP 1.</p>
</div>
-<div class="section" id="abstract">
-<h1><a name="abstract">Abstract</a></h1>
+<div class="section">
+<h1><a id="abstract" name="abstract">Abstract</a></h1>
<p>The memo documents the interfaces, components, and semantics for
disseminating small (smaller than a single packet payload) pieces of
data in TinyOS 2.x. Dissemination is reliably delivering a piece of
data to every node in a network.</p>
</div>
-<div class="section" id="introduction">
-<h1><a name="introduction">1. Introduction</a></h1>
+<div class="section">
+<h1><a id="introduction" name="introduction">1. Introduction</a></h1>
<p>Dissemination is a basic sensor network protocol. The ability to
reliably deliver a piece of data to every node allows administrators
to reconfigure, query, and reprogram a network. Reliability is
document describes a set of components and interfaces for a
dissemination service of this kind.</p>
</div>
-<div class="section" id="dissemination-interfaces">
-<h1><a name="dissemination-interfaces">2. Dissemination interfaces</a></h1>
+<div class="section">
+<h1><a id="dissemination-interfaces" name="dissemination-interfaces">2. Dissemination interfaces</a></h1>
<p>Small-value dissemination has two interfaces: DisseminationValue and
DisseminationUpdate. The former is for consumers of a disseminated
value, the latter is for producers. They are as follows:</p>
<pre class="literal-block">
interface DisseminationValue<t> {
command const t* get();
- event void changed();
+ event void changed();
}
interface DisseminationUpdate<t> {
dissemination protocol therefore MUST have a tie-breaking mechanism,
so that eventually every node has the same data value.</p>
</div>
-<div class="section" id="dissemination-service">
-<h1><a name="dissemination-service">3 Dissemination Service</a></h1>
+<div class="section">
+<h1><a id="dissemination-service" name="dissemination-service">3 Dissemination Service</a></h1>
<p>A dissemination service MUST provide one component, DisseminatorC,
which has the following signature:</p>
<pre class="literal-block">
provides interface DisseminationUpdate <t>;
}
</pre>
-<p>The t argument MUST be able to fit in a single message_t[<a href="#id4" name="id5"><span class="problematic" id="id5">tep111_</span></a>] after
+<p>The t argument MUST be able to fit in a single message_t [TEP111] after
considering the headers that the dissemination protocol introduces.
A dissemination implementation SHOULD have a compile error if a larger
type than this is used.</p>
<p>Two different instances of DisseminatorC MUST NOT share the same value
for the <tt class="docutils literal"><span class="pre">key</span></tt> argument.</p>
</div>
-<div class="section" id="dissemination-keys">
-<h1><a name="dissemination-keys">4 Dissemination Keys</a></h1>
+<div class="section">
+<h1><a id="dissemination-keys" name="dissemination-keys">4 Dissemination Keys</a></h1>
<p>One issue that comes up when using this interfaces is the selection of
a key for each value. On one hand, using unique() is easy, but this
means that the keyspaces for two different compilations of the same
author might write something like this:</p>
<pre class="literal-block">
#include <disseminate_keys.h>
-configuration SomeComponentC {
+configuration SomeComponentC {
...
}
implementation {
#endif
components SomeComponentP;
components new DisseminatorC(uint8_t, DIS_SOME_COMPONENT_KEY);
- SomeComponentP.ConfigVal -> DisseminatorC;
+ SomeComponentP.ConfigVal -> DisseminatorC;
}
</pre>
<p>To override, you can then make a disseminate_keys.h in your app
binaries and not store them. This GUID won't be part of the external
interface, but will be used internally.</p>
</div>
-<div class="section" id="more-complex-dissemination">
-<h1><a name="more-complex-dissemination">5. More Complex Dissemination</a></h1>
+<div class="section">
+<h1><a id="more-complex-dissemination" name="more-complex-dissemination">5. More Complex Dissemination</a></h1>
<p>An application can use this low-level networking primitive to build
more complex dissemination systems. For example, if you want have a
dissemination that only nodes which satisfy a predicate receive, you
data value in it, and layering the predicate evaluation on top of the
above interfaces.</p>
</div>
-<div class="section" id="implementation">
-<h1><a name="implementation">6. Implementation</a></h1>
+<div class="section">
+<h1><a id="implementation" name="implementation">6. Implementation</a></h1>
<p>An implementation of this TEP can be found in
<tt class="docutils literal"><span class="pre">tinyos-2.x/tos/lib/net</span></tt>. This dissemination implementation uses
network trickles <a class="footnote-reference" href="#id3" id="id1" name="id1">[2]</a>. Each dissemination value has a separate
trickle.</p>
</div>
-<div class="section" id="author-s-address">
-<h1><a name="author-s-address">6. Author's Address</a></h1>
+<div class="section">
+<h1><a id="author-s-address" name="author-s-address">6. Author's Address</a></h1>
<div class="line-block">
<div class="line">Philip Levis</div>
<div class="line">358 Gates Hall</div>
<div class="line">email - <a class="reference" href="mailto:gtolle@archedrock.com">gtolle@archedrock.com</a></div>
</div>
</div>
-<div class="section" id="citations">
-<h1><a name="citations">7. Citations</a></h1>
+<div class="section">
+<h1><a id="citations" name="citations">7. Citations</a></h1>
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-<h1><a>Docutils System Messages</a></h1>
-<div class="system-message" id="id4">
-<p class="system-message-title">System Message: <a name="id4">ERROR/3</a> (<tt class="docutils">txt/tep118.txt</tt>, line 116); <em><a href="#id5">backlink</a></em></p>
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