101 lines
3.2 KiB
TeX
101 lines
3.2 KiB
TeX
% !TeX TS-program =
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% !TeX spellcheck = en_DK
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% !TeX encoding = UTF-8
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% !TeX root = ../main.tex
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\chapter{L2 to L3}
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\section{Vlan-to-vlan routing}
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\myquote{}{Guidance and Understanding of the art of Layer 3 networks. Routing between different slash 24\tsq{s}.\\ \textit{Aka. Inter-vlan routing.}}
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There are different ways to go \tsq{bout} Inter-vlan routing and doing it.
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\begin{itemize}
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\item \textbf{Some are using:}
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\begin{enumerate}
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\item external router,
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\item switch virtual interfaces\footnote{\texttt{Switches interface -> Vlan interfaces}},
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\item routed ports\footnote{\texttt{Routed interface -> Subinterfaces}},
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\item bridge virtual interface\footnote{\texttt{L3 bridging interface}}
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\end{enumerate}
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\item \textbf{Ways to do it:}
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\begin{enumerate}
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\item router-on-a-stick if the network is running collapsed core or not have a distribution switch in the middle.
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\item (...)
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\end{enumerate}
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\end{itemize}
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\pagebreak
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\subsection{Interface configs}
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\subsubsection{Routed interfaces}
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\begin{txt}
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interface GigabitEthernet 0/1.10
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encapsulation dot1q 10
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ip address 192.168.0.1 255.255.255.128
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!
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interface GigabitEthernet 0/1.20
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encapsulation dot1q 20
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ip address 192.168.0.129 255.255.255.128
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\end{txt}
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\subsubsection{Switches interfaces}
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\begin{txt}
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Vlan10
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name VLAN10
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Vlan20
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name VLAN20
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!
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interface Vlan10
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ip address 192.168.1.1 255.255.255.128
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interface Vlan20
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ip address 192.168.1.129 255.255.255.128
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!
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interface GigabitEthernet 0/2
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switchport mode trunk
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switchport trunk encapsulation dot1q
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switchport trunk allowed vlan 10,20
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\end{txt}
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\pagebreak
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\fig{network/routeronastick}{routeronastick}{\bsq{Router on a Stick} concept.}
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\pagebreak
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\subsection{? Troubleshooting ?}
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\begin{enumerate}
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\item \textbf{Missing VLAN:}
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\begin{itemize}
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\item VLAN might not be defined across all the switches.
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\item VLAN might not be enabled on the trunk ports.
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\item Ports might not be in the right VLANs.
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\end{itemize}
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\item \textbf{Layer 3 interface misconfiguration:}
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\begin{itemize}
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\item Virtual interface might have the wrong IP address or subnet mask.
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\item Virtual interface might not be up.
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\item Virtual interface number might not match with the VLAN number.
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\item Routing has to be enabled to route frames between VLAN.
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\item Routing might not be enabled.
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\end{itemize}
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\item \textbf{Routing protocol misconfiguration:}
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\begin{itemize}
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\item Eyery interface or network needs to be added in the routing protocol.
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\item The new interface might not be added to the routing protocol.
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\item Routing protocol configuration is needed only if VLAN subnets need to communicate to the other routers, as previously
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mentioned in this chapter.
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\end{itemize}
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\item \textbf{Host misconfiguration:}
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\begin{itemize}
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\item Host might not have the right IP address or subnet mask.
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\item Each host has to have the default gateway that is the SVI or Layer 3 interface to communicate with other networks and VLAN.
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\item Host might not be configured with the default gateway.
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\end{itemize}
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\end{enumerate}
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