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chapter 7: add some new hint and update item indent
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@amirhakh
amirhakh committed Dec 18, 2020
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64 changes: 35 additions & 29 deletions 7 Multicast and realtime service/Multicast and realtime service.tex
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Expand Up @@ -76,14 +76,14 @@ \section{Linux Multicast Routing Table}
Save the new routing table.

\begin{report}
\item Submit the routing table you saved.
\item Submit the routing table you saved.
\end{report}

\section{Multicast Membership}
Execute \lstinline{netstat -g} to show the multicast group memberships for all the interfaces in your host (for example \textit{h1}).

\begin{report}
\item How many multicast groups did the interface belong to? What were the groups? Explain the meaning of the group IDs.
\item How many multicast groups did the interface belong to? What were the groups? Explain the meaning of the group IDs.
\end{report}

\section{Multicast \texttt{ping}}
Expand All @@ -100,11 +100,11 @@ \section{Multicast \texttt{ping}}
\end{lstlisting}

\begin{report}
\item Which hosts replied when the multicast address was pinged?
Which hosts replied when the broadcast address was pinged?
Verify you answers with hosts config \path{/proc/sys/net/ipv4/icmp_echo_ignore_broadcasts}.
\item Which hosts replied when the multicast address was pinged?
Which hosts replied when the broadcast address was pinged?
Verify you answers with hosts config \path{/proc/sys/net/ipv4/icmp_echo_ignore_broadcasts}.

\item In each case, was there a reply from \textit{h0} and \textit{h1}?
\item In each case, was there a reply from \textit{h0} and \textit{h1}?
\end{report}

\section{Multicast vs Unicast}
Expand All @@ -122,11 +122,11 @@ \section{Multicast vs Unicast}
Save the frames captured for the lab report.

\begin{report}
\item Compare the source and destination MAC addresses of the frames you captured.
\item Compare the source and destination MAC addresses of the frames you captured.

\item Use one of the multicast frames captured to explain how a multicast group address is mapped to a multicast MAC address.
For the two multicast frames captured, do they have the same destination MAC address?
Why?
\item Use one of the multicast frames captured to explain how a multicast group address is mapped to a multicast MAC address.
For the two multicast frames captured, do they have the same destination MAC address?
Why?
\end{report}

\section{Simple UDP Multicast Client and Server}
Expand All @@ -148,12 +148,12 @@ \section{Simple UDP Multicast Client and Server}
Save the captured multicast datagram sent by \lstinline{netspyd} and exit the \lstinline{telnet} (or \lstinline{ssh}) session.

\begin{report}
\item From the \lstinline{tcpdump} output, how many messages are sent by \lstinline{netspyd} when a new user logged in to \textit{h0}?
From the \lstinline{netspy} outputs on all the hosts, how many copies of the message are received in total?
\item From the \lstinline{tcpdump} output, how many messages are sent by \lstinline{netspyd} when a new user logged in to \textit{h0}?
From the \lstinline{netspy} outputs on all the hosts, how many copies of the message are received in total?

\item Did \textit{h0}, where the multicast sender, \lstinline{netspyd}, was running, receive the multicast datagram?
Why?
If yes, through which interface did \textit{h0} receive this datagram?
\item Did \textit{h0}, where the multicast sender, \lstinline{netspyd}, was running, receive the multicast datagram?
Why?
If yes, through which interface did \textit{h0} receive this datagram?
\end{report}

\section{\texttt{ping} Replay}
Expand Down Expand Up @@ -255,9 +255,9 @@ \section{Multicast Message}
Now, login to \textit{h1} from \textit{h2} in your group, then logout.

\begin{report}
\item Can you ping a host on the other side of the router?
Will the router forward a multicast IP datagram to the other side?
Justify your answers.
\item Can you ping a host on the other side of the router?
Will the router forward a multicast IP datagram to the other side?
Justify your answers.
\end{report}

\section{IGMP Types}
Expand All @@ -272,10 +272,10 @@ \section{IGMP Types}
Terminate the \lstinline{tcpdump} programs and analyze the IGMP leave message you captured.

\begin{report}
\item What is the value of the Time-to-Live (TTL) field for the IGMP messages?
Why do we not set the TTL to a larger number?
\item What is the value of the Time-to-Live (TTL) field for the IGMP messages?
Why do we not set the TTL to a larger number?

\item What is the default frequency at which the router sends IGMP queries?
\item What is the default frequency at which the router sends IGMP queries?
\end{report}

\section{Router Join to Multicast-Group}
Expand All @@ -286,7 +286,7 @@ \section{Router Join to Multicast-Group}
\end{lstlisting}

\begin{report}
\item Explain why the above command fails.
\item Explain why the above command fails.
\end{report}

\part{Multicast Routing Exercises}\label{sec:multicast-routing}
Expand Down Expand Up @@ -368,10 +368,11 @@ \section{Multicast Multi-Hub}
% Note that most of the router interfaces use their default IP addresses, only the \textit{ethernet0} interface of Router4 needs to be changed to 128.238.63.4.

Enable linux multicast routing in all the hosts (see \autoref{sec:linux-multicast-routing}).

Enable PIM multicast routing in all the routers (see \autoref{sec:config-router}).
All routers pre-configured in \textit{GN3} \hyperref[fig:7.14]{Figure~7.14}

Run \lstinline{tcpdump ip multicast} or \lstinline{wireshark} on all the hosts.
Run \lstinline{tcpdump ip multicast} or \lstinline{wireshark} on all subnet (at least one host).
Maybe you need to restart (or reload) routers to capture all packet from start state.

Execute \lstinline{./netspy 224.111.111.111 1500} on \textit{h0}, \textit{h2}, \textit{h3}, \textit{h5}, and \textit{h6}.

Expand All @@ -383,6 +384,7 @@ \section{Multicast Multi-Hub}
Can you see the \lstinline{netspy} messages on the 128.238.65.0 (or the 128.238.61.0) subnet in the \lstinline{tcpdump} output?

Terminate the \lstinline{netspy} program on \textit{h6} (or \textit{h0}).

Can you see the \lstinline{netspy} messages on the 128.238.65.0 (or the 128.238.61.0) subnet?
\footnote{If IGMPv1 is used, a participant does not send a leave message when it leaves the group.
In this case, the membership record in the router expires in 120 seconds.
Expand All @@ -393,15 +395,19 @@ \section{Multicast Multi-Hub}
What is the destination IP address used in this PIM routing packet?

\begin{report}
\item Answer the above questions.
\item Answer the above questions.
\end{report}

\section{Multicast Tree}
In this exercise, try the \lstinline[language={cisco}]{mstat} Cisco~IOS command to find the multicast tree from a source.
The \lstinline[language={cisco}]{mstat} command is executable in the \textit{Privileged EXEC} mode.
You can always type \lstinline[language={cisco}]{?} to get help on the syntax of the command.

Generate multicast packet when execute command for specific source.
Generate multicast packet when execute command for \textit{h4}.

\begin{report}
\item Report the \lstinline[language={cisco}]{mstat} output for \textit{h4} on \textit{R1}.
\end{report}

\section{Multicast TTL}
Keep \lstinline{netspy} running on all the hosts.
Expand All @@ -427,9 +433,9 @@ \section{Multicast TTL}
Answer the same question.

\begin{report}
\item Answer the above questions.

\item What is the use of the TTL threshold in the router interface?
\item Answer the above questions.
\item What is the use of the TTL threshold in the router interface?
\end{report}

\part{Multicast Video Streaming Exercise}
Expand Down

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