mirror of
https://gitlab.com/netravnen/NetworkLabNotes.git
synced 2024-11-17 18:59:40 +00:00
167 lines
6.5 KiB
TeX
167 lines
6.5 KiB
TeX
\section{Switch Network}
|
|
|
|
\subsection{VTP}
|
|
\fig{vtp/implementing-vtp}{imp-vtp1}{VTP}
|
|
|
|
\subsubsection{VTP Modes}
|
|
The tree modes a VTP \textit{enabled} device can operate are
|
|
\begin{itemize}
|
|
\item Transparent
|
|
\item Server
|
|
\item Client
|
|
\end{itemize}
|
|
Of course you can \textit{disable} VTP altogether.
|
|
|
|
Key things to be aware of \textit{before} enabling VTP in your environment is to make double sure of only having 1 VTP domain. \textbf{If} 2 or more VTP domains exists. Be triple sure to separate them! As to avoid having an VTP server DB overridden with data from another VTP domain.
|
|
|
|
The three VTP modes \textit{operates} as follow
|
|
\begin{itemize}
|
|
\item Transparent
|
|
\begin{itemize}
|
|
\item Creates, modifies and deletes \textit{local} vlans only
|
|
\item Forwards advertisements
|
|
\item Does \textit{not} synchronizes vlan configurations.
|
|
\end{itemize}
|
|
\item Server
|
|
\begin{itemize}
|
|
\item Creates, modifies and deletes vlans
|
|
\item Sends and forwards advertisements
|
|
\item Synchronizes vlan configurations
|
|
\end{itemize}
|
|
\begin{itemize}
|
|
\item Cannot create, modify or delete vlans
|
|
\item Send and forwards advertisements
|
|
\item Synchronizes vlan configurations
|
|
\end{itemize}
|
|
\end{itemize}
|
|
|
|
\subsubsection{VTP Announcement}
|
|
VTP operates with announcements sent out in intervals. Summarized it amounts to
|
|
\begin{itemize}
|
|
\item 1 \textit{summary} announcement per 5th minute from the server
|
|
\item The summary announcement informs clients of the current revision
|
|
\item An announcement is sent out \textit{on the spot} when a change has been made on the VTP server
|
|
\end{itemize}
|
|
|
|
Do remember it is \textbf{only} the VTP server which has the vlan configuration stored \textbf{on disk}. All device clients and transparent nodes do only store the vlans delegated by VTP in memory.
|
|
|
|
\subsubsection{Common Issues}
|
|
\begin{itemize}
|
|
\item Different/Incompatible VTP versions
|
|
\item Wrong password
|
|
\item Incorrect mode name
|
|
\item No server set (all devices configured in transparent/client/vtp disabled mode)
|
|
\end{itemize}
|
|
|
|
\subsubsection{VTP Versions}
|
|
\begin{itemize}
|
|
\item Version 1
|
|
\item Version 2
|
|
\begin{itemize}
|
|
\item Version-dependent transparent mode
|
|
\item Consistencycheck
|
|
\item Token ring support
|
|
\item Unrecognized type-length-value support
|
|
\end{itemize}
|
|
\item Version 3 (not "yet" common)
|
|
\begin{itemize}
|
|
\item Extended VLAN support: Allow ranges are 1-1005,1018-2095. Not mentioned vlans ranges up to 4095 is still reserved.
|
|
\item Domain name is not automatically learned.
|
|
\item Better security.
|
|
\item Better database propagation.
|
|
\item MST now supported.
|
|
\end{itemize}
|
|
\end{itemize}
|
|
|
|
\subsubsection{VTP Pruning}
|
|
The art of only allowing the vlan traffic to flow on \textit{necessary} links.
|
|
|
|
This means if there are no clients in a vlan on a device. Then no traffic for the inactive vlans is send down-/upstream on the link in question.
|
|
\fig{vtp/vtp-pruning}{vtpruning1}{VTP Pruning}
|
|
|
|
\subsubsection{Security}
|
|
It is \textbf{strongly} recommended to enable the security features supported in VTP.
|
|
|
|
\textbf{Password:} MD5 hashing, Case-sensitive, Length between 8 and 64 chars.
|
|
|
|
\notice{VTP Scaling}{
|
|
As the network grows and grows and grows and grows some more over long/short timespans.
|
|
You will \textbf{for certain} come to cross-rode, where you \textbf{must} consider to
|
|
go away from using VTP in the network. The problems of managing an elderly network and
|
|
wiping and re-introducing nodes in the network. You \textbf{will} face the issue of a
|
|
wiped vlan database from the VTP domain.
|
|
}
|
|
|
|
\subsubsection{Example configuration}
|
|
\lstinputlisting{code/vtp/example.cfg}
|
|
|
|
\subsection{Channel Bundling (aka. EtherChannel, PortChannel)}
|
|
Channel bundling is the "art" of using multiple physical links as one single logical link in when viewed from the perspective of the forwarding plane.
|
|
|
|
Technologies:
|
|
\begin{itemize}
|
|
\item \textbf{PAgP:} The Cisco-only thingy
|
|
\item \textbf{LACP:} The IEEE standard
|
|
\item \textbf{Static:} Just forced on
|
|
\end{itemize}
|
|
|
|
\fig{channelbundling/network-without-channelbundling}{noethernetchannel}%
|
|
{No Channelbundling present}
|
|
|
|
Channel bundling of switch ports in the network may or may not be the best idea, in regards to the networks growth rate in terms of min. required bandwidth.
|
|
|
|
Channel bundling spreads out the in and egress flows based upon one of several methods configured on the switch:
|
|
\begin{itemize}
|
|
\item Source to Destination MAC
|
|
\item Source to Destination IP
|
|
\end{itemize}
|
|
Keep in mind this will by no means archive true load balancing. Where all links are equally used based upon number of flows \textit{or} in terms of used bandwidth.
|
|
|
|
\begin{table}[h]
|
|
\centering
|
|
\caption{Channel bundling mechanisms}
|
|
\label{chbundmech1}
|
|
\resizebox{\columnwidth}{!}{%
|
|
\begin{tabular}{|l|l|l|}
|
|
\hline
|
|
Hash Input Code & Hash Input Detecision & Switch Model \\ \hline
|
|
dst-ip & Dest IP addr & All models \\ \hline
|
|
dst-mac & Dest MAC addr & All models \\ \hline
|
|
src-dst-ip & Src and dest IP addr & All models \\ \hline
|
|
src-dst-mac & Src and dest MAC addr & All models \\ \hline
|
|
src-ip & Src IP addr & All models \\ \hline
|
|
src-mac & Src MAC addr & All models \\ \hline
|
|
src-port & Src port no & 4500,6500 \\ \hline
|
|
dst-port & Dest port no & 4500,6500 \\ \hline
|
|
src-dst-port & Src and dest port no & 4500,6500 \\ \hline
|
|
\end{tabular}%
|
|
}
|
|
\end{table}
|
|
|
|
\fig{channelbundling/network-with-channelbundling}{withethernetchannel}%
|
|
{Channelbundling present}
|
|
|
|
\subsubsection{Protocol Properties}
|
|
|
|
\begin{itemize}
|
|
\item LACP
|
|
\begin{itemize}
|
|
\item Active: Enabled
|
|
\item Passive: Waits for LACP packets on the wire before enabled
|
|
\end{itemize}
|
|
\item PAgP
|
|
\begin{itemize}
|
|
\item Desirable: Enabled
|
|
\item Auto: Waits for PAgP packets on the wire before enabled
|
|
\end{itemize}
|
|
\end{itemize}
|
|
|
|
Some other \underline{required} settings to be (equal across all ports) aware of when configuring Channel bundling are
|
|
\begin{enumerate}
|
|
\item Port speeds
|
|
\item Duplex mode
|
|
\item Configured vlan ranges
|
|
\end{enumerate}
|
|
|
|
\subsubsection{Example configuration}
|
|
\lstinputlisting{code/channelbundling/example.cfg} |