ospf.tex

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considering a neighbor dead. If no hello packets are seen from the
neighbor in this time then it is considered dead.
\item{\tt retransmit-interval}: This is the time in seconds between
retransmitting various packets, such as link state update packets or
link state request packets.

\item{\tt authentication}: This directive specifies the authentication
mechanism used to authorise OSPF updates sent and received via this
vif/address.  

The authentication is configured by using one of the following
mutually-exclusive statements:

\begin{description}
\item{\tt simple-password}: this specifies the password used for
  plaintext authentication on this vif/address.
\item{\tt md5}: this specifies an MD5 authentication key. The parameter
  is the key ID and must be in the interval [0, 255].
  The MD5 authentication is configured by using the following
  statements:
\begin{description}
  \item{\tt password}: this specifies the MD5 password for the specific
  key.
  \item{\tt start-time}: this specifies the start time when the key
  becomes active. The format is ``YYYY-MM-DD.HH:MM''. If it is empty,
  then the key should become active immediately.
  \item{\tt end-time}: this specifies the end time when the key becomes
  inactive. The format is ``YYYY-MM-DD.HH:MM''. If it is empty,
  then the key should never expire.
  \item{\tt max-time-drift}: this specifies the maximum time drift
  (in seconds) among all OSPF routers.  The allowed values are in the
  interval [0, 65535]. If the value is 65535, the time drift is
  unlimited. The purpose of this statement is to decide when to start
  accepting the MD5 keys in case other routers's clocks are not
  syncronized and  have started to generate messages with a particular
  key:

\begin{description}
  \item KeyStartAccept = KeyStartGenerate - MaxTimeDrift
  \item KeyStopAccept  = KeyStopGenerate  + MaxTimeDrift
\end{description}

\end{description}

If there are multiple configured keys, among the keys that are valid
for message generation, the one with the most recent {\stt start-time}
(and the largest key ID as a tie breaker) would be used to generate the
messages.

\end{description}
\end{description}

\item{\tt interface}: This specifies a network interface that should
  be used by OSPF for routing.  See Chapter \ref{interfaces} for
  details of interfaces.  The interface must be configured
  in the {\stt interfaces} part of the router configuration.
\begin{description}
\item{\tt link-type}: This specifies the type of the link, {\stt
broadcast}, {\stt p2p} (Point-to-Point) or {\stt p2m} (Point-to-Multipoint).
\begin{description}
\item{\tt vif}: This specifies a vif that should be used by OSPF for routing.
  See Chapter \ref{interfaces} for details of vifs.
\begin{description}
\item{\tt address}: This specifies an IPv4 address that should be used
  by OSPF for routing.  OSPF will peer with other routers on this {\stt
  interface/vif} using this {\stt address}.  The address must be a
  valid configured address for this vif.

  The parameters that can be specified for each address are:
\begin{description}
\item{\tt priority}: This is the priority used to select the
Designated Router on a {\stt broadcast} or {\stt nbma} {\stt
link-type}. The priorities range from 0 to 255. If a value of 0 is
choosen this router will not be a candidate to become the Designated Router
\item{\tt hello-interval}: This is the time in seconds between sending
hello packets.
\item{\tt router-dead-interval}: This is the time in seconds to wait before
considering a neighbor dead. If no hello packets are seen from the
neighbor in this time then it is considered dead.
\item{\tt interface-cost}: The cost for this address that is placed in
the Router-LSA.
\item{\tt retransmit-interval}:  This is the time in seconds between
retransmitting various packets, such as link state update packets or
link state request packets.
\item{\tt transit-delay}: The time to transmit an LSA on this address,
this value is added to the age field of all LSAs.

\item{\tt authentication}: This directive specifies the authentication
mechanism used to authorise OSPF updates sent and received via this
vif/address.  

The authentication is configured by using same configuration statements
as those in case of virtual links (see the {\tt virtual-link}
configuration statement above).

%% The authentication is configured by using one of the following
%% mutually-exclusive statements:

%% \begin{description}
%% \item{\tt simple-password}: this specifies the password used for
%%   plaintext authentication on this vif/address.
%% \item{\tt md5}: this specifies an MD5 authentication key. The parameter
%%   is the key ID and must be in the interval [0, 255].
%%   The MD5 authentication is configured by using the following
%%   statements:
%% \begin{description}
%%   \item{\tt password}: this specifies the MD5 password for the specific
%%   key.
%%   \item{\tt start-time}: this specifies the start time when the key
%%   becomes active. The format is ``YYYY-MM-DD.HH:MM''. If it is empty,
%%   then the key should become active immediately.
%%   \item{\tt end-time}: this specifies the end time when the key becomes
%%   inactive. The format is ``YYYY-MM-DD.HH:MM''. If it is empty,
%%   then the key should never expire.
%%   \item{\tt max-time-drift}: this specifies the maximum time drift
%%   (in seconds) among all OSPF routers.  The allowed values are in the
%%   interval [0, 65535]. If the value is 65535, the time drift is
%%   unlimited. The purpose of this statement is to decide when to start
%%   accepting the MD5 keys in case other routers's clocks are not
%%   syncronized and  have started to generate messages with a particular
%%   key:

%% \begin{description}
%%   \item KeyStartAccept = KeyStartGenerate - MaxTimeDrift
%%   \item KeyStopAccept  = KeyStopGenerate  + MaxTimeDrift
%% \end{description}

%% \end{description}
%% \end{description}

\item{\tt passive}: This takes the value {\stt true} or {\stt
false}. The default setting is {\stt false} it can be set to {\stt
true} to set the interface in loopback. The protocol is no longer run
on this address and the Router-LSA contains a host route for this address.
\item{\tt neighbor}: This allows neighbors to be configured for {\stt
link-type}s of {\stt p2p} or {\stt p2m}. The parameter is the IPv4
address of the neighbor. The {\stt router-id} of the neighbor must
also be configured.
%% \begin{description}
%% \item{\tt router-id}:
%% \end{description}
\item{\tt disable}:  This takes the value {\stt true} or {\stt
false}. The default setting is {\stt false} it can be set to {\stt
true} to disable OSPF on this address without removing all the configuration.
\end{description}
\end{description}
\end{description}
\end{description}

\end{description}
\end{description}

\subsection{Example Configurations}

\vspace{0.1in}
\noindent\framebox[\textwidth][l]{\scriptsize
\begin{minipage}{6in}
\begin{alltt}
\begin{tabbing}
xx\=xx\=xx\=xx\=xx\=\kill
protocols \{\\
\>ospf4 \{\\
\>\>router-id: 10.10.10.10\\
\\
\>\>area 0.0.0.0 \{\\
\>\>\>interface dc0 \{\\
\>\>\>\>vif dc0 \{\\
\>\>\>\>\>address 10.10.10.10 \{\\
\>\>\>\>\>\}\\
\>\>\>\>\}\\
\>\>\>\}\\
\>\>\}\\
\>\}\\
\}\\
\end{tabbing}
\end{alltt}
\end{minipage}
}

This configuration is an example of the minimal possible
configuration. OSPFv2 is running in the {\tt BACKBONE} area, on a single
interface/vif the {\tt router-id} is set to the interface/vif address.

\vspace{0.1in}
\noindent\framebox[\textwidth][l]{\scriptsize
\begin{minipage}{6in}
\begin{alltt}
\begin{tabbing}
xx\=xx\=xx\=xx\=xx\=\kill
protocols \{\\
\>ospf6 \{\\
\>\>router-id: 10.10.10.10\\
\\
\>\>area 0.0.0.0 \{\\
\>\>\>interface dc0 \{\\
\>\>\>\>vif dc0 \{\\
\>\>\>\>\}\\
\>\>\>\}\\
\>\>\}\\
\>\}\\
\}\\
\end{tabbing}
\end{alltt}
\end{minipage}
}

This configuration is an example of the minimal possible
configuration. OSPFv3 is running in the {\tt BACKBONE} area, on a single
interface/vif the {\tt router-id} is set to an an IPv4 address owned
by the router.

\newpage
\section{Monitoring OSPF}

On a router running OSPF, the OSPF routing state can be displayed
using the {\stt show ospf4} or {\stt show ospf6} operational-mode
command. Examples are given below of ospf4 commands equivalent ospf6
commands are available. Information is available about the per area
LSA databases and the status of OSPF adjacencies.

As always, command completion using $<$TAB$>$ or ? will display the
available sub-commands and parameters:

\vspace{0.1in}
\noindent\framebox[\textwidth][l]{\scriptsize
\begin{minipage}{6in}
\begin{alltt}
\begin{tabbing}
xx\=xxxxxxxxxxxxxxxxxxxxx\=\kill
user@hostname> \textbf{show ospf4 ?}\\
Possible completions:\\
\>database\>Show LSA database\\
\>neighbor\>Show Neighbors\\
\>|\>Pipe through a command\\
\end{tabbing}
\end{alltt}
\end{minipage}
}

The {\stt show ospf4 database} command will display information about the
LSAs in the database. Many optional parameters are available to narrow
the search to specific LSA type or to an area. The optional parameter
{\stt detail} will print more information about a LSA. The optional
parameter {\stt summary} prints a count of the LSAs.

\vspace{0.1in}
\noindent\framebox[\textwidth][l]{\scriptsize
\begin{minipage}{6in}
\begin{alltt}
\begin{tabbing}
xx\=xxxxxxxxxxxxxxxxxxxxx\=\kill
user@hostname> \textbf{show ospf4 database ?}\\
Possible completions:\\
\><[Enter]>\>Execute this command\\
\>  area            \>Show LSA database\\
\>  asbrsummary     \>Show Summary-LSA (AS boundary router) database\\
\>  brief           \>Display brief output (default)\\
\>  detail          \>Display detailed output\\
\>  external        \>Show External-LSA database\\
\>  netsummary      \>Show Summary-LSA (network) database\\
\>  network         \>Show Network-LSA database\\
\>  nssa            \>Show NSSA-LSA database\\
\>  router          \>Show Router-LSA database\\
\>  summary         \>Display summary output\\
\>|\>Pipe through a command\\
\end{tabbing}
\end{alltt}
\end{minipage}
}

\newpage
The {\stt show ospf4 database} command with no modifiers will show all
LSA types in all areas:

\vspace{0.1in}
\noindent\framebox[\textwidth][l]{\scriptsize
\begin{minipage}{6in}
\begin{alltt}
\begin{tabbing}
%%\=xxxxxxxxx\=xxxxxxxxxxxxxxxxxx\=xxxxxxxxxxxxxxxxxx\=xxxxxxxx\=xxxxxxxx\=xxxxxxxx\=xxxxxxxx\=xxxxxxxx\=xxxxxxxx\=\kill
user@hostname> \textbf{show ospf4 database}\\
   OSPF link state database, Area 0.0.0.0\\
\=xxxxxxxxxxxx\=xxxxxxxxxxxxxxxx\=xxxxxxxxxxxxxxxx\=xxxxxxxx\=xxxxx\=xxxxx\=xxxxxxx\=\kill
\>Type\>       ID\>               Adv Rtr\>           Seq\>      Age\>  Opt\>  Cksum\>  Len\\
\=xxxxxxxx\=x\=xxxxxxxxxxxxxxxx\=xxxxxxxxxxxxxxxx\=xxxxxxxxxxx\=xxxxx\=xxxxx\=xxxxxxx\=\kill
\>Router\>*\>  192.150.187.112\>192.150.187.112\>0x8000018f\>1444\>0x2\>  0x9d24\>          36\\
\>Network\>\>  192.150.187.99\>   192.150.187.99\>   0x80000054\>   167\>  0x22\> 0x7c63\>  40\\
\>SummaryN\>*\>172.16.0.0\>       192.150.187.112\>  0x80000188\>  1453\>  0x2\>  0x9df5\>  28\\
\>SummaryN\>*\>172.16.1.0\>       192.150.187.112\>  0x80000188\>  1453\>  0x2\>  0x92ff\>  28\\
\>SummaryN\>*\>172.16.2.0\>       192.150.187.112\>  0x80000188\>  1453\>  0x2\>  0x870a\>  28\\
\>Router\>\>   192.150.187.99\>   192.150.187.99\>   0x80000e76\>   167\>  0x22\> 0xddf7\>  36\\
\>Router\>\>   192.150.187.5\>    192.150.187.5\>    0x800004a6\>   983\>  0x2\>  0x40a8\>  36\\
\>Router\>\>   192.150.187.108\>  192.150.187.108\>  0x80000301\>   598\>  0x2\>  0xb9a1\>  36\\
\>ASExt-2\>\>  172.16.0.0\>       192.150.187.5\>    0x800003a9\>   990\>  0x2\>  0x77c1\>  36\\
   OSPF link state database, Area 0.0.0.13\\
\=xxxxxxxxxxxx\=xxxxxxxxxxxxxxxx\=xxxxxxxxxxxxxxxx\=xxxxxxxx\=xxxxx\=xxxxx\=xxxxxxx\=\kill
\>Type\>       ID\>               Adv Rtr\>           Seq\>      Age\>  Opt\>  Cksum\>  Len\\
\=xxxxxxxx\=x\=xxxxxxxxxxxxxxxx\=xxxxxxxxxxxxxxxx\=xxxxxxxxxxx\=xxxxx\=xxxxx\=xxxxxxx\=\kill
\>Router\>*\>  192.150.187.112\>  192.150.187.112\>  0x80000001\>  1454\>  0x2\>  0x8a03\>  36\\
\>SummaryN\>*\>192.150.187.0\>    192.150.187.112\>  0x80000001\>  1443\>  0x2\>  0x4ef6\>  28\\
\>SummaryN\>*\>172.16.1.0\>       192.150.187.112\>  0x80000001\>  1453\>  0x2\>  0xa476\>  28\\
\>SummaryN\>*\>172.16.2.0\>       192.150.187.112\>  0x80000001\>  1453\>  0x2\>  0x9980\>  28\\
\>SummaryR\>*\>192.150.187.5\>    192.150.187.112\>  0x80000001\>  1443\>  0x2\>  0xbb4\>   28\\
\>ASExt-2\>\>  172.16.0.0\>       192.150.187.5\>    0x800003a9\>   990\>  0x2\>  0x77c1\>  36\\
   OSPF link state database, Area 0.0.0.2\\
\=xxxxxxxxxxxx\=xxxxxxxxxxxxxxxx\=xxxxxxxxxxxxxxxx\=xxxxxxxx\=xxxxx\=xxxxx\=xxxxxxx\=\kill
\>Type\>       ID\>               Adv Rtr\>           Seq\>      Age\>  Opt\>  Cksum\>  Len\\
\=xxxxxxxx\=x\=xxxxxxxxxxxxxxxx\=xxxxxxxxxxxxxxxx\=xxxxxxxxxxx\=xxxxx\=xxxxx\=xxxxxxx\=\kill
\>Router\>*\>  192.150.187.112\>  192.150.187.112\>  0x80000001\>  1454\>  0x2\>  0x93f8\>  36\\
\>SummaryN\>*\>192.150.187.0\>    192.150.187.112\>  0x80000001\>  1443\>  0x2\>  0x4ef6\>  28\\
\>SummaryN\>*\>172.16.0.0\>       192.150.187.112\>  0x80000001\>  1453\>  0x2\>  0xaf6c\>  28\\
\>SummaryN\>*\>172.16.2.0\>       192.150.187.112\>  0x80000001\>  1453\>  0x2\>  0x9980\>  28\\
\>SummaryR\>*\>192.150.187.5\>    192.150.187.112\>  0x80000001\>  1443\>  0x2\>  0xbb4\>   28\\
\>ASExt-2\>\>  172.16.0.0\>       192.150.187.5\>    0x800003a9\>   990\>  0x2\>  0x77c1\>  36\\
   OSPF link state database, Area 0.0.0.3\\
\=xxxxxxxxxxxx\=xxxxxxxxxxxxxxxx\=xxxxxxxxxxxxxxxx\=xxxxxxxx\=xxxxx\=xxxxx\=xxxxxxx\=\kill
\>Type\>       ID\>               Adv Rtr\>           Seq\>      Age\>  Opt\>  Cksum\>  Len\\
\=xxxxxxxx\=x\=xxxxxxxxxxxxxxxx\=xxxxxxxxxxxxxxxx\=xxxxxxxxxxx\=xxxxx\=xxxxx\=xxxxxxx\=\kill
\>Router\>*\>  192.150.187.112\>  192.150.187.112\>  0x80000001\>  1454\>  0x2\>  0x9cee\>  36\\
\>SummaryN\>*\>192.150.187.0\>    192.150.187.112\>  0x80000001\>  1443\>  0x2\>  0x4ef6\>  28\\
\>SummaryN\>*\>172.16.0.0\>       192.150.187.112\>  0x80000001\>  1453\>  0x2\>  0xaf6c\>  28\\
\>SummaryN\>*\>172.16.1.0\>       192.150.187.112\>  0x80000001\>  1453\>  0x2\>  0xa476\>  28\\
\>SummaryR\>*\>192.150.187.5\>    192.150.187.112\>  0x80000001\>  1443\>  0x2\>  0xbb4\>   28\\
\>ASExt-2\>\>  172.16.0.0\>       192.150.187.5\>    0x800003a9\>   990\>  0x2\>  0x77c1\>  36\\
\end{tabbing}
\end{alltt}
\end{minipage}
}

The {\stt show ospf4 neighbor} command will show state of adjacencies:

\vspace{0.1in}
\noindent\framebox[\textwidth][l]{\scriptsize
\begin{minipage}{6in}
\begin{alltt}
\begin{tabbing}
user@hostname> show ospf4 neighbor\\
\=xxxxxxxxxxxxxxxx\=xxxxxxxxxxxxxxxxxxxx\=xxxxxxxxx\=xxxxxxxxxxxxxxxx\=xxxx\=\kill
\>  Address\>         Interface\>             State\>      ID\>              Pri\>  Dead\\
\>192.150.187.5\>    fxp0/fxp0\>              Full\>      192.150.187.5\>    150\>    34\\
\>192.150.187.99\>   fxp0/fxp0\>              Full\>      192.150.187.99\>   128\>    34\\
\>192.150.187.108\>  fxp0/fxp0\>              TwoWay\>    192.150.187.108\>  128\>    34\\
\>192.150.187.78\>   fxp0/fxp0\>              Down\>      0.0.0.78\>           0\>     0\\
\end{tabbing}
\end{alltt}
\end{minipage}
}

\newpage
The {\stt show ospf4 neighbor detail} command will show state of
adjacencies with extra detail such as the Designated Router and the
time the adjacency has been up:

\vspace{0.1in}
\noindent\framebox[\textwidth][l]{\scriptsize
\begin{minipage}{6in}
\begin{alltt}
\begin{tabbing}
user@hostname> show ospf4 neighbor detail\\
\=xxxxxxxxxxxxxxxx\=xxxxxxxxxxxxxxxxxxxx\=xxxxxxxxx\=xxxxxxxxxxxxxxxx\=xxxx\=\kill
\>  Address\>         Interface\>             State\>      ID\>              Pri\>  Dead\\
\>192.150.187.5\>    fxp0/fxp0\>              Full\>      192.150.187.5\>    150\>    33\\
\=xxxxxxxxxxxxxxxxxx\=xxxxxxxxx\=xxxxxxxxxxxxxxxxxxx\=\kill
\>  Area 0.0.0.0,\> opt 0x2,\> DR 192.150.187.99,\> BDR 192.150.187.5\\
\>  Up 54:09:26,\> adjacent 54:09:16\\
\=xxxxxxxxxxxxxxxx\=xxxxxxxxxxxxxxxxxxxx\=xxxxxxxxx\=xxxxxxxxxxxxxxxx\=xxxx\=\kill
\>192.150.187.99\>   fxp0/fxp0\>              Full\>      192.150.187.99\>   128\>    38\\
\=xxxxxxxxxxxxxxxxxx\=xxxxxxxxx\=xxxxxxxxxxxxxxxxxxx\=\kill
\>  Area 0.0.0.0,\> opt 0x2,\> DR 192.150.187.99,\> BDR 192.150.187.5\\
\>  Up 54:09:26,\> adjacent 54:09:16\\
\=xxxxxxxxxxxxxxxx\=xxxxxxxxxxxxxxxxxxxx\=xxxxxxxxx\=xxxxxxxxxxxxxxxx\=xxxx\=\kill
\>192.150.187.108\>  fxp0/fxp0\>              TwoWay\>    192.150.187.108\>  128\>    33\\
\=xxxxxxxxxxxxxxxxxx\=xxxxxxxxx\=xxxxxxxxxxxxxxxxxxx\=\kill
\>  Area 0.0.0.0,\> opt 0x2,\> DR 192.150.187.99,\> BDR 192.150.187.5\\
\>  Up 54:09:26\\
\=xxxxxxxxxxxxxxxx\=xxxxxxxxxxxxxxxxxxxx\=xxxxxxxxx\=xxxxxxxxxxxxxxxx\=xxxx\=\kill
\>192.150.187.78\>   fxp0/fxp0\>              Down\>      0.0.0.78\>           0\>    0\\
\=xxxxxxxxxxxxxxxxxx\=xxxxxxxxx\=xxxxxxxxxxxxxxxxxxx\=\kill
\>  Area 0.0.0.0,\> opt 0,\> DR 0.0.0.0,\> BDR 0.0.0.0\\
\>  Up 14:47:32\\
\end{tabbing}
\end{alltt}
\end{minipage}
}