diff --git a/06-Lehrer_STP.md b/06-Lehrer_STP.md
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+---
+title: Spanning Tree Protocol (STP)
+author: Carl Kittelberger
+
+papersize: a4
+classoption: oneside
+mainfont: Arial
+sansfont: Arial
+
+header-includes:
+  - \usepackage{longtable}
+---
+
+![](img/06-stp/stp_3node.png)
+
+*Schleife in der Verkabelung erzeugt Broadcaststurm!*
+
+Ein Switch im Netz wird als **Root-Switch** festgelegt.
+Switches unterhalten sich über **BPDUs** (*Bridge Protocol Data Units*).
+Der Switch mit der höchsten Priorität wird der Root-Switch.
+
+Jeder Switch bekomment eine Switch-Kennung:
+
+![](img/06-stp/stp_swid.png){width=200px}
+
+Jeder Switch aktiviert *eine* Leitung zum Root-Switch hin.
+
+→ Netz wird auf einen logischen Baum reduziert
+→ **Spannbaum** (*Spanning Tree*)
+
+→ Jedes Teilstück der Verbindung wird mit "Kosten" belegt.
+
+→ Der Pfad von Switch zum Root-Switch mit den geringsten Gesamtkosten (**Root-Path-costs**) wird aktiviert.
+→ **Rootpath**. Der Port am Switch, der zum Root führt ist der **Rootport**.
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+# Images generated by LibreOffice Draw
+*.png
+*.svg
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