From c2b9f0d4c7abb7609381aacdafb3936a97db3419 Mon Sep 17 00:00:00 2001
From: Camil Staps
Date: Mon, 23 May 2016 21:51:53 +0200
Subject: Assignment 7, deel 2

---
 assignment7.tex | 47 +++++++++++++++++++++++++++++++++++++++++------
 1 file changed, 41 insertions(+), 6 deletions(-)

(limited to 'assignment7.tex')

diff --git a/assignment7.tex b/assignment7.tex
index bf9ea1e..5be9ff5 100644
--- a/assignment7.tex
+++ b/assignment7.tex
@@ -91,20 +91,55 @@
 
 \section{Address Resolution Protocol}
 \begin{enumerate}
-	\item
-			A --- 192.168.1.100; B --- 192.168.1.200;\\
-			C --- 192.168.2.100; D --- 192.168.2.200;\\
-			E --- 192.168.3.100; F --- 192.168.3.200.
 	\item We call the left router R and the right router S. Let $R_i$ be the
 		interface of router $R$ for subnet $i$. Then:
 
+			A --- 192.168.1.100; B --- 192.168.1.200;\\
+			C --- 192.168.2.100; D --- 192.168.2.200;\\
+			E --- 192.168.3.100; F --- 192.168.3.200;\\
+			R$_1$ --- 192.168.1.1; R$_2$ --- 192.168.2.1;\\
+			S$_2$ --- 192.168.2.2; S$_3$ --- 192.168.3.2;\\
+
+	\item
 		A --- 00.00.00.00.00.A0; B --- 00.00.00.00.00.B0;\\
 		C --- 00.00.00.00.00.C0; D --- 00.00.00.00.00.D0;\\
 		E --- 00.00.00.00.00.E0; F --- 00.00.00.00.00.F0;\\
 		R$_1$ --- 88.88.88.00.00.00; R$_2$ --- 88.88.88.00.88.00;\\
 		S$_2$ --- 88.88.88.88.00.00; S$_3$ --- 88.88.88.88.88.00.
-	\item %todo
-	\item %todo
+
+	\item Host E looks up the MAC address of the first hop router (S$_3$), and
+		sends the datagram there. Router S receives the datagram, figures out that
+		the next hop is router R, looks up the MAC address of R$_2$ and sends the
+		datagram there. Router R then forwards the datagram in a frame to host B on
+		interface R$_1$. Concretely, the following frames are sent:
+
+		\begin{table}[h]
+			\centering
+			\begin{tabular}{l | l | l | l}
+				Src. IP       & Src. MAC          & Dest. IP      & Dest. MAC \\\hline
+				192.168.3.100 & 00.00.00.00.00.E0 & 192.168.3.2   & 88.88.88.88.88.00\\
+				192.168.2.2   & 88.88.88.88.88.00 & 192.168.2.1   & 88.88.88.00.88.00\\
+				192.168.1.1   & 88.88.88.00.88.00 & 192.168.1.200 & 00.00.00.00.00.B0\\
+			\end{tabular}
+		\end{table}
+
+	\item The same happens, but before E can send the frame to S$_3$, it has to
+		get to know its address. It sends an ARP request to the broadcast address
+		with the request for 192.168.3.2's (that is, S$_3$'s) MAC address. The
+		router replies with an ARP packet. After this, E has all the addresses it
+		needs (and all other nodes as well), so the same as above happens.
+
+		\begin{table}[h]
+			\centering
+			\begin{tabular}{l | l | l | l | l}
+				Src. IP       & Src. MAC          & Dest. IP      & Dest. MAC         & Protocol\\\hline
+				192.168.3.100 & 00.00.00.00.00.E0 & 192.168.3.2   & FF.FF.FF.FF.FF.FF & ARP\\
+				192.168.3.2   & 88.88.88.88.88.00 & 192.168.3.100 & 00.00.00.00.00.E0 & ARP\\
+				192.168.3.100 & 00.00.00.00.00.E0 & 192.168.3.2   & 88.88.88.88.88.00 & IP\\
+				192.168.2.2   & 88.88.88.88.88.00 & 192.168.2.1   & 88.88.88.00.88.00 & IP\\
+				192.168.1.1   & 88.88.88.00.88.00 & 192.168.1.200 & 00.00.00.00.00.B0 & IP\\
+			\end{tabular}
+		\end{table}
 \end{enumerate}
 
 \section{Self-learning}
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