pimsm.tex

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  \item Apply additional system configuration (if necessary):

  \begin{itemize}

    \item {\tt DragonFlyBSD}:

    IPv4: Enable IPv4 unicast forwarding:

\begin{verbatim}
sysctl net.inet.ip.forwarding=1
\end{verbatim}

    IPv6: Enable IPv6 unicast forwarding:

\begin{verbatim}
sysctl net.inet6.ip6.forwarding=1
\end{verbatim}

    \item {\tt FreeBSD}:

    IPv4: Enable IPv4 unicast forwarding:

\begin{verbatim}
sysctl net.inet.ip.forwarding=1
\end{verbatim}

    IPv6: Enable IPv6 unicast forwarding:

\begin{verbatim}
sysctl net.inet6.ip6.forwarding=1
\end{verbatim}

    \item {\tt Linux}:

    IPv4: Enable IPv4 unicast forwarding:

\begin{verbatim}
echo 1 > /proc/sys/net/ipv4/ip_forward
\end{verbatim}

    If the unicast Reverse Path Forwarding information is different from the
    multicast Reverse Path Forwarding information, the Return Path Filtering
    should be disabled:

\begin{verbatim}
echo 0 > /proc/sys/net/ipv4/conf/all/rp_filter
\end{verbatim}
    OR
\begin{verbatim}
echo 0 > /proc/sys/net/ipv4/conf/eth0/rp_filter
echo 0 > /proc/sys/net/ipv4/conf/eth1/rp_filter
...
\end{verbatim}

    IPv6: unknown

    \item {\tt NetBSD}: none.

    \item {\tt OpenBSD}: Add the following lines to {\stt /etc/rc.conf.local}
    and reboot:

\begin{verbatim}
# Enable multicast routing (see netstart(8) for details).
multicast_host=NO
multicast_router=YES
\end{verbatim}

  \end{itemize}

\end{itemize}

\subsection{Configuring Multicast Tunnels on UNIX Systems}

All PIM routers need to be directly connected so they can exchange
control messages. Occasionally this might not be possible (\eg if
someone wants to forward multicast traffic to a remote host, and the
routers in the middle are not running PIM).

In that case a tunnel between two remote routers can be used to create
an artificial adjacency.

\begin{itemize}

  \item Creating a GRE tunnel.

  The GRE (Generic Routing Encapsulation) mechanism is described in RFC
  1701 and RFC 1702. It is implemented on a variety of systems and is
  widely used for routing tunnels.

  Below is an example how to configure a GRE tunnel between two Linux
  systems.

\begin{verbatim}
# GRE tunnel between two machines (host 11.11.11.11 and 33.33.33.33)
#
# Physical interfaces:    [11.11.11.11]         [33.33.33.33]
# GRE tunnel:              22.22.22.11<--------->22.22.22.33
#

# ==== host 11.11.11.11 (GRE interface 22.22.22.11)
ip link set gre1 down
ip tunnel del gre1
ip tunnel add gre1 mode gre remote 33.33.33.33 local 11.11.11.11 ttl 127
ip addr add 22.22.22.11/24 peer 22.22.22.33/24 dev gre1
ip link set gre1 up multicast on

# ==== host 33.33.33.33 (GRE interface 22.22.22.33)
ip link set gre1 down
ip tunnel del gre1
ip tunnel add gre1 mode gre remote 11.11.11.11 local 33.33.33.33 ttl 127
ip addr add 22.22.22.33/24 peer 22.22.22.11/24 dev gre1
ip link set gre1 up multicast on
\end{verbatim}


  \item Creating an OpenVPN tunnel.

  OpenVPN (http://openvpn.net/) is free software to create a VPN tunnel.
  It is very popular and works on a variety of systems.
  One of the advantages of OpenVPN is that it is over TCP or UDP,
  hence unlike GRE it does not require special support from NAT devices
  that might be in the middle.

  Below is an example how to configure an OpenVPN tunnel.

\begin{verbatim}
# OpenVPN tunnel between two machines (host 11.11.11.11 and 33.33.33.33)
#
# Physical interfaces:    [11.11.11.11]         [33.33.33.33]
# OpenVPN tunnel:          22.22.22.11<--------->22.22.22.33
#

# ==== host 11.11.11.11 (OpenVPN interface 22.22.22.11)
openvpn --local 11.11.11.11 --remote 33.33.33.33 --ifconfig 22.22.22.11
    22.22.22.33 --dev tun0

# ==== host 33.33.33.33 (OpenVPN interface 22.22.22.33)
openvpn --local 33.33.33.33 --remote 11.11.11.11 --ifconfig 22.22.22.33
    22.22.22.11 --dev tun0
\end{verbatim}

  \item Reverse Path Forwarding (RPF) information setup.

  It is important that the Reverse Path Forwarding (RPF) information
  is set to consider the tunnel for PIM-SM to operate properly.

  On Linux systems the following UNIX command needs to be used to
  disable the Return Path filtering:

\begin{verbatim}
echo 0 > /proc/sys/net/ipv4/conf/all/rp_filter
\end{verbatim}

  In addition, the RPF information must be set appropriately for all
  systems that are suppose to be reached via the tunnel (\eg RPs and
  remote sources). This can be achieved by adding MRIB-specific static
  routing entries in the XORP configuration. For example, if the IP
  address of the other side of the tunnel is 22.22.22.33, then the
  following XORP configuration can be used to specify that the tunnel is
  the default route for all destinations:

\begin{verbatim}
protocols {
    static {
        mrib-route 0.0.0.0/0 {
            next-hop 22.22.22.33
        }
    }
}
\end{verbatim}

\end{itemize}

\newpage
\subsection{Configuration Syntax}

\vspace{0.1in}
\noindent\framebox[\textwidth][l]{\scriptsize
\begin{minipage}{4.5in}
\begin{alltt}
\begin{tabbing}
xx\=xx\=xx\=xx\=xx\=\kill
protocols \{\\
\>pimsm4 \{\\
\>\>targetname: {\it text}\\
\>\>disable: {\it bool}\\
\>\>interface {\it text} \{\\
\>\>\>vif {\it text} \{\\
\>\>\>\>disable: {\it bool}\\
\>\>\>\>enable-ip-router-alert-option-check: {\it bool}\\
\>\>\>\>dr-priority: {\it uint}\\
\>\>\>\>hello-period: {\it uint(1..18724)}\\
\>\>\>\>hello-triggered-delay: {\it uint(1..255)}\\
\>\>\>\>alternative-subnet {\it IPv4}/{\it int(0..32)}\\
\>\>\>\}\\
\>\>\}\\
\>\>interface register\_vif \{\\
\>\>\>vif register\_vif \{\\
\>\>\>\>disable: {\it bool}\\
\>\>\>\}\\
\>\>\}\\
\\
\>\>static-rps \{\\
\>\>\>rp {\it IPv4} \{\\
\>\>\>\>group-prefix {\it IPv4Mcast}/{\it int(4..32)} \{\\
\>\>\>\>\>rp-priority: {\it uint(0..255)}\\
\>\>\>\>\>hash-mask-len: {\it uint(4..32)}\\
\>\>\>\>\}\\
\>\>\>\}\\
\>\>\}\\
\\
\>\>bootstrap \{\\
\>\>\>disable: {\it bool}\\
\>\>\>cand-bsr \{\\
\>\>\>\>scope-zone  {\it IPv4Mcast}/{\it int(4..32)} \{\\
\>\>\>\>\>is-scope-zone: {\it bool}\\
\>\>\>\>\>cand-bsr-by-vif-name: {\it text}\\
\>\>\>\>\>cand-bsr-by-vif-addr: {\it IPv4}\\
\>\>\>\>\>bsr-priority: {\it uint(0..255)}\\
\>\>\>\>\>hash-mask-len: {\it uint(4..32)}\\
\>\>\>\>\}\\
\>\>\>\}\\
\\
\>\>\>cand-rp \{\\
\>\>\>\>group-prefix  {\it IPv4Mcast}/{\it int(4..32)} \{\\
\>\>\>\>\>is-scope-zone: {\it bool}\\
\>\>\>\>\>cand-rp-by-vif-name: {\it text}\\
\>\>\>\>\>cand-rp-by-vif-addr: {\it IPv4}\\
\>\>\>\>\>rp-priority: {\it uint(0..255)}\\
\>\>\>\>\>rp-holdtime: {\it uint(0..65535)}\\
\>\>\>\>\}\\
\>\>\>\}\\
\>\>\}\\
\\
\>\>switch-to-spt-threshold \{\\
\>\>\>disable: {\it bool}\\
\>\>\>interval: {\it uint(3..2147483647)}\\
\>\>\>bytes: {\it uint}\\
\>\>\}\\
\\
{\rm continued overleaf....}
\end{tabbing}
\end{alltt}
\end{minipage}
}
\newpage
\vspace{0.1in}
\noindent\framebox[\textwidth][l]{\scriptsize
\begin{minipage}{4.5in}
\begin{alltt}
\begin{tabbing}
xx\=xx\=xx\=xx\=xx\=\kill
\>\>traceoptions \{\\
\>\>\>flag all \{\\
\>\>\>\>disable: {\it bool}\\
\>\>\>\}\\
\>\>\}\\
\>\}\\
\}
\\
\\
protocols \{\\
\>pimsm6 \{\\
\>\>disable: {\it bool}\\
\>\>interface {\it text} \{\\
\>\>\>vif {\it text} \{\\
\>\>\>\>disable: {\it bool}\\
\>\>\>\>enable-ip-router-alert-option-check: {\it bool}\\
\>\>\>\>dr-priority: {\it uint}\\
\>\>\>\>hello-period: {\it uint(1..18724)}\\
\>\>\>\>hello-triggered-delay: {\it uint(1..255)}\\
\>\>\>\>alternative-subnet  {\it IPv6}/{\it int(0..128)}\\
\>\>\>\}\\
\>\>\}\\
\>\>interface register\_vif \{\\
\>\>\>vif register\_vif \{\\
\>\>\>\>disable: {\it bool}\\
\>\>\>\}\\
\>\>\}\\
\\
\>\>static-rps \{\\
\>\>\>rp {\it IPv6} \{\\
\>\>\>\>group-prefix  {\it IPv6Mcast}/{\it int(8..128)} \{\\
\>\>\>\>\>rp-priority: {\it uint(0..255)}\\
\>\>\>\>\>hash-mask-len: {\it uint(8..128)}\\
\>\>\>\>\}\\
\>\>\>\}\\
\>\>\}\\
\\
\>\>bootstrap \{\\
\>\>\>disable: {\it bool}\\
\>\>\>cand-bsr \{\\
\>\>\>\>scope-zone {\it IPv6Mcast}/{\it int(8..128)} \{\\
\>\>\>\>\>is-scope-zone: {\it bool}\\
\>\>\>\>\>cand-bsr-by-vif-name: {\it text}\\
\>\>\>\>\>cand-bsr-by-vif-addr: {\it IPv6}\\
\>\>\>\>\>bsr-priority: {\it uint(0..255)}\\
\>\>\>\>\>hash-mask-len: {\it uint(8..128)}\\
\>\>\>\>\}\\
\>\>\>\}\\
\\
\>\>\>cand-rp \{\\
\>\>\>\>group-prefix {\it IPv6Mcast}/{\it int(8..128)} \{\\
\>\>\>\>\>is-scope-zone: {\it bool}\\
\>\>\>\>\>cand-rp-by-vif-name: {\it text}\\
\>\>\>\>\>cand-rp-by-vif-addr: {\it IPv6}\\
\>\>\>\>\>rp-priority: {\it uint(0..255)}\\
\>\>\>\>\>rp-holdtime: {\it uint(0..65535)}\\
\>\>\>\>\}\\
\>\>\>\}\\
\>\>\}\\
\\
\>\>switch-to-spt-threshold \{\\
\>\>\>disable: {\it bool}\\
\>\>\>interval: {\it uint(3..2147483647)}\\
\>\>\>bytes: {\it uint}\\
\>\>\}\\
\\
\>\>traceoptions \{\\
\>\>\>flag all \{\\
\>\>\>\>disable: {\it bool}\\
\>\>\>\}\\
\>\>\}\\
\>\}\\
\}
\end{tabbing}
\end{alltt}
\end{minipage}
}
\vspace{0.1in}

\begin{description}
\item{\tt protocols}: this delimits the configuration for all routing
  protocols in the XORP router configuration.  It is mandatory that
  PIM-SM configuration is under the {\stt protocols} node in the
  configuration.
\item{\tt pimsm4}: this delimits the PIM-SM configuration part of the XORP
  router configuration related to IPv4 multicast.
\item{\tt targetname}: this is the name for this instance of PIM-SM for
  IPv4.  It defaults to ``{\stt PIMSM\_4}'', and it is not recommended
  that this default is overridden under normal usage scenarios.
\item{\tt disable}: this takes the value {\stt true} or {\stt false},
  and indicates whether PIM-SM IPv4 multicast routing is currently
  disabled~\footnote{Note
  that prior to XORP Release-1.1, the {\tt enable} flag was used instead of
  {\tt disable}.}.
  This allows multicast to be taken down temporarily without
  removing the configuration.
\item{\tt interface}: this directive specifies that this {\stt
  interface} is to be used for PIM-SM IPv4 multicast routing.  The