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\ihead{CCNA v7.02: SRW (Switching, Routing, and Wireless Essentials)}
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\ohead{kohnlehome.de/cisco/CCNA-2-05.pdf}
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\ifoot{Franz Kohnle}
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\begin{document}

% Überschrift 
\begin{center}
    \LARGE % Schriftgröße
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    5 STP Concepts
\end{center}

\section*{5.1 Purpose of STP}
\begin{itemize}
    \item Redundancy, Loop-Free, Issues: MAC address table instability, link saturation, high CPU utilization
    \item Vgl. Layer 3: TTL, Hop Limit
    \item Layer 2 Loop: Broadcast Storm
    \item The Spanning Tree Algorithm
    \begin{itemize}
        \item Select the Root Bridge
        \item Block Redundant Paths
        \item Loop-Free Topology
        \item Link Failure Causes Recalculation        
    \end{itemize}
\end{itemize}


\section*{5.2 STP Operations}
\begin{itemize}
    \item Steps to a Loop-Free Topology
    \begin{itemize}
        \item Elect the root bridge: kleinste BID
        \item Elect the root ports (1 pro Switch): kleinste Root Path Cost
        \item Elect designated ports (1 pro Segment): am nächsten zur Root-Bridge
        \item Elect alternate (blocked) ports (alle anderen Porsts)       
    \end{itemize}
    \item BPDU (Bridge Protocol Data Unit)
    \begin{itemize}
        \item BID (Bridge ID)
        \begin{itemize}
            \item Bridge Priority (4 bit): Vielfache von 4096. Default 32768. Je kleiner, umso besser
            \item Extended Sytem ID (12 bit): = VLAN-ID
            \item MAC Address (48 bit)            
        \end{itemize}
    \end{itemize}
    \item STP Timer
    \begin{itemize}
        \item Hello Timer
        \item Forward Delay Timer
        \item Max Age Timer        
    \end{itemize}
    \item Port States
    \begin{itemize}
        \item Blocking
        \item Listening
        \item Learning
        \item Forwarding
        \item Disabled
    \end{itemize}
    \item PVST (Per-VLAN Spanning Tree): jedes VLAN kann eigenen Root-Bridge haben
\end{itemize}


\section*{5.3 Evolution of STP}
\begin{itemize}
    \item Different Versions of STP
    \begin{itemize}
        \item STP, PVST+, 802.1D-2004
        \item RSTP, Rapid PVST+
        \item MSTP, MST    
    \end{itemize}
    \item RSTP Port States and Port Roles
    \item PortFast and BPDU Guard
    \item Alternatives to STP
\end{itemize}




\end{document}
