Tentative "Babel protocol extension" section

slides.tex

@@ -10,14 +10,25 @@
 \usepackage{texlib/todo}
 
 \usepackage{booktabs}
-\usepackage[normalem]{ulem}
+\usepackage[thicklines]{cancel}
+
+\renewcommand{\CancelColor}{\color{red}}
 
 %\usepackage{inconsolata}
 
+
+\lstdefinelanguage{iproute} {
+    morekeywords={inet6},
+    sensitive=true,
+}
+
+
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 \title{Announcing IPv4 routes with an IPv6 next-hop in the Babel
 routing protocol}
-\subtitle{\textit{aka.} draft-bastian-babel-v4ov6}
+\subtitle{\textit{aka.}
+    \href{https://datatracker.ietf.org/doc/draft-bastian-babel-v4ov6/}{
+draft-bastian-babel-v4ov6}}
 \author[\slidecountline]
 {Théophile Bastian, Juliusz Chroboczek}
 \date{}
@@ -34,7 +45,8 @@ routing protocol}
 
 \begin{frame}{Traditional routing}
     \begin{align*}
-        \text{Network prefix (IPvX)} &\longrightarrow \text{Next-Hop (IPvX)}
+        \text{Network prefix (IPvX)} \quad &\longrightarrow
+        \quad \text{Next-Hop (IPvX)}
     \end{align*}
 
     \pause{}
@@ -50,12 +62,11 @@ routing protocol}
             default & & 10.42.0.254 \\
             10.102.0.0/16 & & 10.102.0.1 \\
             10.102.10.0/24 & & 10.102.10.1 \\
-            \only<3>{10.0.0.0/8 & & \sout{fd80:1::1}} \\
+            \only<3>{10.0.0.0/8 & & % \makebox[0pt]{\color{red}---}
+            \xcancel{fd80:1::1}} \\
             \bottomrule
         \end{tabular}
     \end{table}
-
-    \todo{Better strikeout}
 \end{frame}
 
 \begin{frame}{The router's job}
@@ -89,9 +100,72 @@ routing protocol}
         \item IPv6 has \alert{link-local} and \alert{automatic addresses}
             (SLAAC)
             \begin{itemize}
-                \item no need for DHCP or IP configuration \emph{at all}!
+                \item no need for DHCP or IP addresses configuration \emph{at all}!
             \end{itemize}
     \end{itemize}
 \end{frame}
 
+\begin{frame}[fragile]{Supported in Linux since 5.2}
+    \begin{block}{d1566268 -- 2019-04-05 -- ipv4: Allow ipv6 gateway with ipv4 routes}
+        \quad{}Add support for \lstbash{RTA_VIA} and allow an IPv6 nexthop for v4
+        routes.
+    \end{block}
+
+    \vspace{1em}
+
+    \begin{itemize}
+        \item{} Usually, add a v4 route with
+            \begin{lstlisting}[language=iproute, numbers=none]
+# ip route add 10.42.0.0/16 via 10.40.0.42 dev eno1
+            \end{lstlisting}
+
+        \item{} v4-over-v6 (recent kernel):
+            \begin{lstlisting}[language=iproute, numbers=none]
+# ip route add 10.42.0.0/16 via inet6 fe80::a0de:baf:b39b dev eno1
+            \end{lstlisting}
+    \end{itemize}
+
+\end{frame}
+
+\section{Babel protocol extension}
+
+\begin{frame}{Advertising v4-over-v6 routes}
+    \textbf{An IPv4 interface} never announces v4-over-v6 routes
+
+    \vspace{1em}
+
+    \textbf{A v6-only interface}
+    \begin{itemize}
+        \item{} \alert{Installs a v4 route} nevertheless when receiving it
+        \item{} \alert{Announces a v4-over-v6 route} for each v4 route
+    \end{itemize}
+\end{frame}
+
+\begin{frame}{Introducing a new AE}
+    In Babel, \alert{Address Encodings} (AEs) define the type of address/prefix
+    contained in a TLV.
+    \begin{itemize}
+        \item IPv4 address
+        \item IPv6 address
+        \item link-local IPv6 address
+        \item[$\bigstar$] \alert{v4-over-v6 address}
+    \end{itemize}
+\end{frame}
+
+\begin{frame}{Backwards compatibility}
+    \textbf{With older implementations}
+    \begin{itemize}
+        \item Ignore v4-over-v6 routes
+        \item No state updates missed
+    \end{itemize}
+
+    \vspace{2em}
+
+    \textbf{With older kernels}
+    \begin{itemize}
+        \item Won't advertise a route that cannot be locally set
+        \item In babeld, detect kernel version
+    \end{itemize}
+\end{frame}
+
 \end{document}