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Diffstat (limited to 'what-is-iot-slides.tex')
| -rw-r--r-- | what-is-iot-slides.tex | 150 |
1 files changed, 128 insertions, 22 deletions
diff --git a/what-is-iot-slides.tex b/what-is-iot-slides.tex index bf541c1..15841a0 100644 --- a/what-is-iot-slides.tex +++ b/what-is-iot-slides.tex @@ -361,9 +361,8 @@ maximum value is 64k, 65536.} \end{frame} -\hypertarget{lecture-esp8266-aka-nodemcu-aka-esp-12}{% -\section{Lecture: ESP8266 aka NodeMCU aka -ESP-12}\label{lecture-esp8266-aka-nodemcu-aka-esp-12}} +\hypertarget{lecture-esp8266}{% +\section{Lecture: ESP8266}\label{lecture-esp8266}} \begin{frame}{ESP8266 software layers} \protect\hypertarget{esp8266-software-layers}{} @@ -423,7 +422,7 @@ Agents have one of two roles: \item Handles network connections \item - Keeps subscription state + Keeps subscriptions \item Manages client @@ -435,11 +434,14 @@ Agents have one of two roles: \emph{(last) will} \end{itemize} \item - Persistence + Persistence of retained messages \end{itemize} \end{itemize} -\note{http://docs.oasis-open.org/mqtt/mqtt/v3.1.1/mqtt-v3.1.1.html +\note{network connections: this includes removing closed sockets, +client’s that doesn’t respons to timeouts and duplicate clients. + +http://docs.oasis-open.org/mqtt/mqtt/v3.1.1/mqtt-v3.1.1.html Subscriptions are not permanent. The connection is (unlike HTTP) stateful. @@ -537,22 +539,16 @@ altert levels (autonomous operation)} \begin{itemize} \tightlist \item - Very small -\end{itemize} - -\begin{itemize} -\tightlist -\item - Packet type + flags + Size oriented \item - Packet identifier -\item - Payload + Flags indicate type of remaining bytes \begin{itemize} \tightlist \item - Size + Packet type + \item + Topic name \item Payload \end{itemize} @@ -608,6 +604,114 @@ The central application is split: \end{frame} +\begin{frame}[fragile]{MQTT - The protocol - Retained message} +\protect\hypertarget{mqtt---the-protocol---retained-message}{} + +Message is kept by the server even after disconnect + +\begin{itemize} +\tightlist +\item + \texttt{CONNECT} +\item + \texttt{PUBLISH} + + \begin{itemize} + \tightlist + \item + \texttt{RETAIN} + \item + \texttt{\$app/\$device/temperature} + \item + \texttt{22.3} + \end{itemize} +\item + \texttt{DISCONNECT} +\end{itemize} + +Later on: + +\begin{itemize} +\tightlist +\item + \texttt{SUBSCRIBE} + + \begin{itemize} + \tightlist + \item + \texttt{\$app/\#/temperature} + \end{itemize} +\item + \texttt{PUBLISH} + + \begin{itemize} + \tightlist + \item + \texttt{\$app/\$device/temperature} + \item + \texttt{22.3} + \end{itemize} +\end{itemize} + +\note{The last PUBLISH is an incoming message} + +\end{frame} + +\begin{frame}[fragile]{MQTT - The protocol - Will message} +\protect\hypertarget{mqtt---the-protocol---will-message}{} + +Message sent when you disconnect + +Client \#1: + +\begin{enumerate} +[1.] +\tightlist +\item + \texttt{CONNECT} + + \begin{itemize} + \tightlist + \item + \texttt{WILL\ TOPIC:\ \$app/\$device/online} + \item + \texttt{WILL\ PAYLOAD:\ 0} + \end{itemize} +\item + \texttt{PUBLISH} + + \begin{itemize} + \tightlist + \item + \texttt{\$app/\$device/online} + \item + \texttt{1} + \end{itemize} +\item + \texttt{DISCONNECT} +\end{enumerate} + +\ldots{} + +Broker + +\begin{enumerate} +[1.] +\tightlist +\item + \texttt{PUBLISH} + + \begin{itemize} + \tightlist + \item + \texttt{\$app/\$device/online} + \item + \texttt{0} + \end{itemize} +\end{enumerate} + +\end{frame} + \begin{frame}{MQTT - Patterns} \protect\hypertarget{mqtt---patterns}{} @@ -618,13 +722,15 @@ Explain: \begin{itemize} \tightlist \item - Message sizes with MQTT -\item - “will” messages -\item Push vs pull, central applications can push to clients \item mostly mqtt, some http +\item + Client id - sparker ut gamle koblinger +\item + Keep alive / ping meldinger +\item + Alternative transporter - websockets(!) \end{itemize} \end{frame} @@ -667,7 +773,7 @@ releases at the same time.} \item Microsoft Azure IoT \item - CloudMQTT + CloudMQTT (at Heroku) \end{itemize} \item DIY |