256 lines
7.9 KiB
TeX
256 lines
7.9 KiB
TeX
% vim: spell spelllang=en
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\documentclass[11pt,xcolor={usenames,dvipsnames},aspectratio=169]{beamer}
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\usetheme{metropolis}
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\usepackage[utf8]{inputenc}
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\usepackage[english]{babel}
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\usepackage[T1]{fontenc}
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\usepackage{texlib/my_listings}
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\usepackage{texlib/todo}
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\usepackage{booktabs}
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\usepackage[thicklines]{cancel}
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\renewcommand{\CancelColor}{\color{red}}
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%\usepackage{inconsolata}
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\lstdefinelanguage{iproute} {
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morekeywords={inet6},
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sensitive=true,
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}
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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\title{Announcing IPv4 routes with an IPv6 next-hop in the Babel
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routing protocol}
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\subtitle{\textit{aka.}
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\href{https://datatracker.ietf.org/doc/draft-bastian-babel-v4ov6/}{
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draft-bastian-babel-v4ov6}}
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\author[\slidecountline]
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{Théophile Bastian, joint work with Juliusz Chroboczek}
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\date{}
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%\subject{}
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%\logo{}
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\institute{
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\href{https://ens.fr/}{ENS Paris},
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\href{https://www.irif.fr/}{IRIF},
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\href{https://www.nexedi.com/}{Nexedi}}
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\begin{document}
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\maketitle{}
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\begin{frame}{Traditional routing}
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\begin{table}
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\centering
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\textbf{IPv4 routing table} \\
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\medskip
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\begin{tabular}{@{} lcl @{}}
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\toprule
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Network Prefix (IPvX) & $\rightarrow$ & Next-Hop (IPvX)\\
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\midrule
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default & & 10.42.0.254 \\
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10.102.0.0/16 & & 10.102.0.1 \\
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10.102.0.0/24 & & 10.102.0.2 \\
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10.0.0.0/8 & & \xcancel{fd80:1::1} \\
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\bottomrule
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\end{tabular}
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\end{table}
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\vspace{1em}
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\begin{itemize}
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\item \textbf{Control plan:} \alert{babel}, routing protocol.
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\alert{Fills the routing table}.
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\item \textbf{Data plan:} correctly forward incoming packets.
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\alert{Uses the routing table}.
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\end{itemize}
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\end{frame}
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\begin{frame}{The router's job}
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\begin{figure}
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\centering
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\includegraphics[width=\columnwidth]{imgs/pdf/routing.pdf}
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\end{figure}
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\end{frame}
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\begin{frame}{What's under the hood?}
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\begin{figure}
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\centering
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\only<1>{\includegraphics[width=\columnwidth]{imgs/_autogen/mac/01.pdf}}
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\only<2>{\includegraphics[width=\columnwidth]{imgs/_autogen/mac/02.pdf}}
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\only<3>{\includegraphics[width=\columnwidth]{imgs/_autogen/mac/03.pdf}}
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\only<4>{\includegraphics[width=\columnwidth]{imgs/_autogen/mac/04.pdf}}
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\only<5>{\includegraphics[width=\columnwidth]{imgs/_autogen/mac/05.pdf}}
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\only<6>{\includegraphics[width=\columnwidth]{imgs/_autogen/mac/06.pdf}}
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\only<7>{\includegraphics[width=\columnwidth]{imgs/_autogen/mac/07.pdf}}
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\only<8>{\includegraphics[width=\columnwidth]{imgs/_autogen/mac/08.pdf}}
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\only<9>{\includegraphics[width=\columnwidth]{imgs/_autogen/mac/09.pdf}}
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\only<10>{\includegraphics[width=\columnwidth]{imgs/_autogen/mac/10.pdf}}
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\only<11>{\includegraphics[width=\columnwidth]{imgs/_autogen/mac/11.pdf}}
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\only<12>{\includegraphics[width=\columnwidth]{imgs/_autogen/mac/12.pdf}}
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\end{figure}
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\end{frame}
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\begin{frame}{The idea behind}
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\textbf{New type of route!} v4 prefix with v6 next-hop: \alert{v4-over-v6
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route}.
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\vspace{2em}
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\begin{itemize}
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\item Supporting both v4 and v6 is cumbersome: twice the configuration
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\item v6-only core, still serve v4 to clients
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\item IPv6 has \alert{link-local} and \alert{automatic addresses}
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(SLAAC)
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\begin{itemize}
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\item no need for DHCP or IP addresses configuration \emph{at all}!
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\end{itemize}
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\end{itemize}
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\vspace{2em}
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\textbf{Not an original idea!} BGP had it first:
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\href{https://datatracker.ietf.org/doc/draft-ietf-bess-rfc5549revision/}{draft-ietf-bess-rfc5549revision}
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\end{frame}
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\begin{frame}[fragile]{Linux support}
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\textbf{Supported in Linux} since 5.2 --~July 2019!
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\begin{minipage}[c]{0.1\textwidth}
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\includegraphics[height=1.2em]{imgs/Git-Logo-1788C}
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\end{minipage}
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\begin{minipage}[c]{0.85\textwidth}
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\begin{block}{d1566268 -- 2019-04-05 -- ipv4: Allow ipv6 gateway with ipv4 routes}
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\quad{}Add support for \lstbash{RTA_VIA} and allow an IPv6 nexthop for v4
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routes.
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\end{block}
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\end{minipage}
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\vspace{2em}
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\begin{itemize}
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\item{} Usually, add a v4 route with
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\begin{lstlisting}[language=iproute, numbers=none]
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# ip route add 10.42.0.0/16 via 10.40.0.42 dev eno1
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\end{lstlisting}
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\item{} v4-over-v6 (recent kernel):
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\begin{lstlisting}[language=iproute, numbers=none]
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# ip route add 10.42.0.0/16 via inet6 fe80::a0de:baf:b39b dev eno1
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\end{lstlisting}
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\end{itemize}
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\end{frame}
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\section{Babel protocol extension}
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\begin{frame}{Advertising v4-over-v6 routes}
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\textbf{An IPv4 interface} never announces v4-over-v6 routes
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\vspace{1em}
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\textbf{A v6-only interface}
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\begin{itemize}
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\item{} \alert{Installs a v4 route} nevertheless when receiving it
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\item{} \alert{Announces a v4-over-v6 route} for each v4 route
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\end{itemize}
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\end{frame}
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\begin{frame}{Backwards compatibility}
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\textbf{\alert{Backwards compatibility:} an unextended node \alert{must}}
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\begin{itemize}
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\item Be able to \alert{ignore v4-over-v6 routes}
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\item \alert{Route correctly} pure v4 and v6
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\end{itemize}
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\vspace{2em}
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In Babel, \alert{Address Encodings} (AEs) define the type of address/prefix
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contained in a TLV\@.
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\begin{itemize}
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\item IPv4 address
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\item IPv6 address
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\item link-local IPv6 address
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\end{itemize}
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\end{frame}
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\begin{frame}{Encoding v4-over-v6 routes: choices}
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\begin{enumerate}
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\item An IPv4 route announced without previously setting a valid
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next-hop is considered v4-over-v6.
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\begin{itemize}
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\item Is backwards compatible --~but not obviously so
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\item Not clear an extension is being used
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\end{itemize}
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\item New specific AE for v4-over-v6 routes, and next-hop
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is\ldots{}
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\begin{enumerate}[i]
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\item \ldots{}specific to v4-over-v6 routes
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\item \only<1>{\ldots{}same as for v6 routes}
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\only<2>{\textbf{\alert{\ldots{}same as for v6 routes}}}
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\begin{itemize}
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\item[$\rightarrow$] more compact, just as clear
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\end{itemize}
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\end{enumerate}
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\medskip
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\begin{itemize}
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\item Backwards compatible and clean
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\item A tiny bit more verbose
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\end{itemize}
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\end{enumerate}
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\medskip
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\only<2>{
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\begin{center}
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\textbf{
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{\Large $\leadsto$} 2.ii. \alert{Add a new AE.} No need for new
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TLVs.
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}
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\end{center}
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}
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\end{frame}
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%%%%%%%%%%% Conclusion frame %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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\begin{frame}{To sum up}
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\begin{itemize}
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\item While routing, next-hop address is \alert{only useful to get layer 2
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address}
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\item New type of route: \alert{v4-over-v6}, v4 destination, v6 next-hop
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\item Less network configuration, same features! Yay!
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\item We have \alert{an extension draft} and \alert{an implementation}
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\end{itemize}
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\vspace{2em}
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\begin{columns}[T]
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\begin{column}{0.5\textwidth}
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\centering
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\textbf{\large RFC draft}
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\href{https://datatracker.ietf.org/doc/draft-bastian-babel-v4ov6/}{\texttt{\large huit.re/draft-v4ov6}}
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\includegraphics[width=0.25\textwidth]{imgs/pdf/qr_draft.pdf}
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\end{column}
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\begin{column}{0.5\textwidth}
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\centering
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\textbf{\large These slides}
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\href{https://tobast.fr/files/ietf108-v40v6.pdf}{\texttt{\large huit.re/ietf108-v4ov6}}
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\includegraphics[width=0.25\textwidth]{imgs/pdf/qr_slide.pdf}
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\end{column}
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\end{columns}
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\end{frame}
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\end{document}
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