X-Git-Url: https://git.rohieb.name/skm-ma-ws1314.git/blobdiff_plain/9c0186068ed8d750cbae9dae7740f312a7663fe8..2ef57bbd89d873de5a76d1053966cb53dec5af47:/sec-discussion.tex

diff --git a/sec-discussion.tex b/sec-discussion.tex
index 0f05d0c..534bb25 100644
--- a/sec-discussion.tex
+++ b/sec-discussion.tex
@@ -3,7 +3,7 @@
 \subsection{Future Work}
 
 In addition to the XEPs covered above, there are a few additional XEPs which can
-be implemented to further increase the effictivity of Chatty Things. Especially
+be implemented to further increase the effectivity of Chatty Things. Especially
 the documents XEP-0323 through XEP-0326 (which are currently in Experimental
 status) are targeted to the Internet of Things.
 
@@ -24,15 +24,6 @@ interested in specific values then only needs to communicate with a single node
 in the network.
 
 \paragraph{Sensor Data (XEP-0323)~\cite{xep0323}}
-%\begin{figure}
-  %\caption{Example stream between a sensor node and a client}
-  %\label{fig:streamexample}
-  %\begin{verbatim}
-%Client               Device
-%<stream>
-
-  %\end{verbatim}
-%\end{figure}
 This XEP specifies a way of reading out values from a
 sensor node. It allows to specify multiple data sources (e.~g. temperature,
 humidity) as well as multiple types of data (e.~g., momentary values, historical
@@ -43,6 +34,14 @@ accepts the request by returning a corresponding IQ stanza. If it has
 accepted the request, it reads out the requested data and returns it in a
 subsequent message stanza to the client.
 
+An example of this protocol can be seen in Figure~\ref{fig:examplexmpp}: after
+both clients have opened their streams, the client requests the momentary values
+for power and energy from the node named \emph{Device04}. The device first
+acknowledges this request, and, after retrieving the values, sends them back
+to the client.
+
+\input{fig-example-xmpp-stream.tex}
+
 \paragraph{Control (XEP-0325)~\cite{xep0325}} In this document, a way of
 controlling sensor nodes is specified, which allows a client to get and set
 control values on the node over message or IQ stanzas. As an example, in this
@@ -75,9 +74,6 @@ it is to be noted that this requires further implementation of compression
 algorithms as well as additional CPU and memory resources and thus might
 decrease message throughput and increase power consumption on embedded systems.
 
-
-\todo{example XML stream with sensor data}
-
 \subsection{Related Approaches}
 
 ``Chatty Things'' is not the only approach to implement communication in
@@ -93,7 +89,7 @@ summarized in Table~\ref{tab:comparison}.
   \hline
   Feature & Chatty Things & CoAP & MQTT & WS4D \\
   \hline\hline
-  application gateways neccessary & - & yes & yes & - \\ \hline
+  application gateways necessary & - & yes & yes & - \\ \hline
   usable with standard clients & yes & - & - & (yes) \\ \hline
   discovery support & yes & yes & - & yes\\ \hline
   IPv6/6LoWPAN ready & yes & yes & ? & partial \\ \hline
@@ -109,7 +105,7 @@ machine-to-machine communication and originates from the IETF Constrained
 Resources Working Group\footnote{\url{http://datatracker.ietf.org/wg/core/}},
 but still has been only in draft status since 2010.\ It allows a mapping to
 HTTP, and is therefore stateless, but it specifies a binary protocol, which
-makes it neccessary to deploy application-level gateways and special client
+makes it necessary to deploy application-level gateways and special client
 software to communicate with its environment. It relies on UDP, but emulates
 congestion control, message confirmation and message IDs, since â in contrast to
 HTTP â messages can be sent asynchronously. Discovery is also specified and done
@@ -146,7 +142,7 @@ For communication, standard APIs can be used.
 protocol, there is the need to implement at least an XML parser on each node,
 which comes with protocol overhead and increased code size. However Klauck and
 Kirsche show that with good optimization (in the code as well as in the
-procotol), a complete stack can be implemented in 12 kByte of ROM, which leaves
+protocol), a complete stack can be implemented in 12 kBytes of ROM, which leaves
 enough space for other applications to be built onto it. As compared to Web
 Services, Chatty Things are probably not as flexible, but they have less
 overhead, even when using XML, while MQTT and CoAP provide less flexibility for
