slides.tex

xorp源码hg

\documentclass[landscape]{icsislides}

\usepackage[dvips]{graphicx}
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%\usepackage{subfigure}
\usepackage[T1]{fontenc}
\usepackage{psfrag}
\usepackage{xspace}
\usepackage{alltt}
\usepackage{colordvi}

\newcommand{\etc}{\emph{etc.}\xspace}
\newcommand{\ie}{\emph{i.e.,}\xspace}
\newcommand{\eg}{\emph{e.g.,}\xspace}

%\def\makeslidenum#1{\Gray{\fontseries{u}\selectfont#1}}%

%% XXX: comment-out to include logo
\newlogo{}

\begin{document}

%%======================================================================
\begin{titlepage}

\begin{center}
{\LARGE \Red{XORP: An eXtensible Open Router Platform}} \\
\vskip20pt

\vskip100pt
\begin{tabular}{c}
Atanu Ghosh \qquad Mark Handley \qquad Orion Hodson \\
Eddie Kohler \qquad \textbf{Pavlin Radoslavov} \\
\Gray{International Computer Science Institute}
\end{tabular}

\vskip-5pt
\begin{tabular}{c@{\qquad\qquad}c}
Adam Greenhalgh & Luigi Rizzo \\
\Gray{University College London} & \Gray{University of Pisa}
\end{tabular}
\end{center}

\end{titlepage}

% %%======================================================================
% \begin{titlepage}

% \begin{center}
% {\LARGE \bf XORP}
% \end{center}
% \vspace*{1.0in}
% \begin{center}
% Pavlin Radoslavov\\
% \vspace*{0.5in}
% \small {\it [e-mail]}\\
% \small International Computer Science Institute\\
% \small Berkeley, CA, USA
% \end{center}

% \end{titlepage}

%%======================================================================
\begin{slide}
\slidetitle{Outline}

\begin{enumerate}
  \item Motivations
  \item XORP introduction
  \item XORP IPC mechanism
  \item What does it take to implement a routing protocol?
  \item Dependency tracking mechanism
  \item Conclusions
\end{enumerate}

\end{slide}

%%======================================================================
\begin{slide}
\slidetitle{Networking research: divorced from reality?}

\begin{itemize}
  \item Gap between research and practice

  \item Most of the important Internet protocols originated in research

  \item It used to be that researchers designed systems, \emph{build
  implementations}, \emph{tried them out}, and standardized the ones that
  \emph{survived and proved useful}.

  \item What happened?

\end{itemize}

\end{slide}

%%======================================================================
\begin{slide}
\slidetitle{Networking research: why the divorce?}

\begin{itemize}
  \item The commercial Internet
  \begin{itemize}
    \item Network stability is critical, so experimentation is difficult
    \item Major infrastructure vendors not motivated to support
    experimentation
  \end{itemize}

  \item Network simulators
  \begin{itemize}
    \item Nice tool, but usually too abstract from reality
  \end{itemize}

\end{itemize}

\end{slide}

%%======================================================================
\begin{slide}
\slidetitle{Simulation is not a substitute for experimentation}

\begin{itemize}
  \item Many questions require real-world traffic and/or routing information

  \item Many people:
  \begin{itemize}
    \item Give up, implement their protocol in \emph{ns}
    \item Set \emph{ns} parameters based on guesses, existing scripts
    \item Write a paper that may or may not bear any relationship to reality
  \end{itemize}

  \item We need to be able to run experiments when required!

\end{itemize}

\end{slide}

%%======================================================================
\begin{slide}
\slidetitle{Options}

\begin{itemize}
  \item Option 1:
  \begin{itemize}
    \item Persuade Cisco to implement your protocol;
    \item Persuade ISPs that your protocol won't destabilize their networks;
    \item Conduct experiment.
  \end{itemize}

\end{itemize}

\end{slide}

%%======================================================================
\begin{slide}
\slidetitle{Options (cont.)}

\begin{itemize}
  \item Option 2:
  \begin{itemize}
    \item Implement routing protocol part in MRTd, GateD, or Zebra;
    \item Implement forwarding part in FreeBSD, Linux, Click, etc;
    \item Persuade network operators to replace their Ciscos with your PC;
    \item Conduct experiment.
  \end{itemize}

\end{itemize}

\end{slide}

%%======================================================================
\begin{slide}
\slidetitle{Likelihood of success?}

\begin{center}
  \includegraphics[width=6.0in]{figs/flyingpig}
\end{center}

\end{slide}

%%======================================================================
\begin{slide}
\slidetitle{Possible solutions}

\begin{itemize}

  \item Solution 1: A router vendor opens their development environment and
  APIs:
  \begin{itemize}
    \item Third-party router applications
    \item Basic router functionality cannot be changed
  \end{itemize}

  \item Solution 2: Someone (\emph{hint, hint}) builds a complete open-source
  router software stack explicitly designed for {\bf extensibility} and
  {\bf robustness}:
  \begin{itemize}
    \item Adventurous network operators deploy this router on their
    networks
    % it develops a reputation for stability and configurability.
    \item Result: a fully extensible platform suitable for {\bf research} and
    {\bf deployment}
  \end{itemize}
\end{itemize}

\end{slide}

%%======================================================================
\begin{slide}
\slidetitle{XORP: eXtensible Open Router Platform}

Complete software stack for an IP router:

\begin{itemize}
  \item Routing protocols: unicast and multicast
  \begin{itemize}
    \item Protocols can be run in simulation-like environment
  \end{itemize}
  \item Management Interfaces
  \item Forwarding path
\end{itemize}

\end{slide}

%%======================================================================
\begin{slide}
\slidetitle{XORP Architecture}

\begin{center}
  \includegraphics[width=6.0in]{figs/xorp_arch}
\end{center}

\end{slide}

%%======================================================================
\begin{slide}
\slidetitle{Challenges}

\begin{itemize}

  \item {\bf Features}: real-world routers support a long feature list

  \item {\bf Extensibility}:
  \begin{itemize}
    \item Every aspect of the router should be extensible
    \item Multiple extensions should be able to coexist
  \end{itemize}

  \item {\bf Performance}: raw forwarding performance; routing table size (not
  core routers; even edge routing is hard enough)

  \item {\bf Robustness}: must not crash or misroute packets

\end{itemize}

\end{slide}

%%======================================================================
\begin{slide}
\slidetitle{XORP Features}

\begin{itemize}

  \item IPv4 and \Gray{IPv6}

  \item Unicast routing protocols: BGP4+, OSPF, RIPv2/RIPng, \Gray{IS-IS}

  \item Multicast: PIM-SM/\Gray{SSM}, IGMPv1,2,\Gray{3}/MLDv1,\Gray{2}

  \item \Gray{DHCP, PPP}

  \item Management: CLI, \Gray{SNMP}, \Gray{WWW}

  \item Forwarding path: UNIX (native), Click

\end{itemize}

\end{slide}

%%======================================================================
\begin{slide}
\slidetitle{Extensibility: Intra-router APIs}

Separate abstract request (API) from concrete request (which process?
which arguments? which version?)

In particular, the caller:
\begin{itemize}
  \item Should not care about IPC mechanism
  \item Should not know in advance which process is relevant
  \dots unless required
\end{itemize}

\end{slide}

%%======================================================================
\begin{slide}
\slidetitle{Extensibility: XRLs (XORP Resource Locators)}

XORP IPC mechanism (like URLs for IPC):

\begin{center}
\texttt{finder://fea/fea/1.0/add\char`\_address4?vif:txt=fxp0\&addr:ipv4=10.0.0.1}
\vskip20pt
\end{center}

\begin{itemize}
  \item Library marshals arguments, implements transport, handles responses
  \item Redirection into a single XRL or an XRL sequence
  \item Programmer explicitly handles failure
\end{itemize}

\end{slide}

\def\LN#1{\setbox0\hbox{\lower\baselineskip\hbox{\rmfamily\BrickRed{#1}}}\wd0=0pt\ht0=0pt\dp0=0pt\box0\relax}
\def\RN#1{\setbox0\hbox{\lower\baselineskip\hbox to0pt{\hskip0pt plus-1000pt \rmfamily\BrickRed{#1}}}\ht0=0pt\dp0=0pt\box0\relax}
\let\t\texttt

%%======================================================================
\begin{slide}
\slidetitle{Extensibility: XRLs (XORP Resource Locators)}

XORP IPC mechanism (like URLs for IPC):

\begin{center}
\texttt{\LN{IPC mechanism: \t{finder}, \t{xudp}, \t{snmp}, \dots}\Red{finder}://fea/fea/1.0/add\char`\_address4?vif:txt=fxp0\&addr:ipv4=10.0.0.1}
\vskip20pt
\end{center}

\begin{itemize}
  \item Library marshals arguments, implements transport, handles responses
  \item Redirection into a single XRL or an XRL sequence
  \item Programmer explicitly handles failure
\end{itemize}

\end{slide}

%%======================================================================
\begin{slide}
\slidetitle{Extensibility: XRLs (XORP Resource Locators)}

XORP IPC mechanism (like URLs for IPC):

\begin{center}
\texttt{finder://\LN{Module/process name: \t{fea}, \t{rib}, \t{bgp}, \dots}\Red{fea}/fea/1.0/add\char`\_address4?vif:txt=fxp0\&addr:ipv4=10.0.0.1}
\vskip20pt
\end{center}

\begin{itemize}
  \item Library marshals arguments, implements transport, handles responses
  \item Redirection into a single XRL or an XRL sequence
  \item Programmer explicitly handles failure
\end{itemize}

\end{slide}

%%======================================================================
\begin{slide}
\slidetitle{Extensibility: XRLs (XORP Resource Locators)}

XORP IPC mechanism (like URLs for IPC):

\begin{center}
\texttt{finder://fea/\LN{Interface name: \t{fea}, \t{routing-process}, \dots}\Red{fea}/1.0/add\char`\_address4?vif:txt=fxp0\&addr:ipv4=10.0.0.1}
\vskip20pt
\end{center}

\begin{itemize}
  \item Library marshals arguments, implements transport, handles responses
  \item Redirection into a single XRL or an XRL sequence
  \item Programmer explicitly handles failure
\end{itemize}

\end{slide}

%%======================================================================
\begin{slide}
\slidetitle{Extensibility: XRLs (XORP Resource Locators)}

XORP IPC mechanism (like URLs for IPC):

\begin{center}
\texttt{finder://fea/fea/\LN{Version number}\Red{1.0}/add\char`\_address4?vif:txt=fxp0\&addr:ipv4=10.0.0.1}
\vskip20pt
\end{center}

\begin{itemize}
  \item Library marshals arguments, implements transport, handles responses
  \item Redirection into a single XRL or an XRL sequence
  \item Programmer explicitly handles failure
\end{itemize}

\end{slide}

%%======================================================================
\begin{slide}
\slidetitle{Extensibility: XRLs (XORP Resource Locators)}

XORP IPC mechanism (like URLs for IPC):

\begin{center}
\texttt{finder://fea/fea/1.0/\LN{Method name: \t{delete\char`\_address4},
\t{get\char`\_mtu}, \dots}\Red{add\char`\_address4}?vif:txt=fxp0\&addr:ipv4=10.0.0.1}
\vskip20pt
\end{center}

\begin{itemize}
  \item Library marshals arguments, implements transport, handles responses
  \item Redirection into a single XRL or an XRL sequence
  \item Programmer explicitly handles failure
\end{itemize}

\end{slide}

%%======================================================================
\begin{slide}
\slidetitle{Extensibility: XRLs (XORP Resource Locators)}

XORP IPC mechanism (like URLs for IPC):

\begin{center}
\texttt{finder://fea/fea/1.0/add\char`\_address4?\LN{Arguments}\Red{vif:txt=fxp0\&addr:ipv4=10.0.0.1}}
\vskip20pt
\end{center}

\begin{itemize}
  \item Library marshals arguments, implements transport, handles responses
  \item Redirection into a single XRL or an XRL sequence
  \item Programmer explicitly handles failure
\end{itemize}

\end{slide}

%%======================================================================
\begin{slide}
\slidetitle{Defining XRL interface}

XRL interface is defined in XRL-specific files:

\begin{verbatim}
interface pim/0.1 {
	/**
	 * Enable a PIM virtual interface.
	 *
	 * @param vif_name the name of the vif to enable.
	 * @param fail true if failure has occurred.
	 * @param reason contains failure reason if it occurred.
	 */
	enable_vif	? vif_name:txt	-> fail:bool & reason:txt

	...
}
\end{verbatim}