Remove old EPC documentation
This commit is contained in:
Robert Schmidt
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\documentclass[a4paper,oneside]{report}
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\usepackage{pgfplots}
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\ifx\HCode\UnDef\else\def\pgfsysdriver{pgfsys-tex4ht.def}\fi
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\usepackage{verbatim}
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\usepackage{listings}
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\usepackage{tikz,graphicx}
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\usepackage{caption}
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\usepackage{float}
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\usepackage{hyperref}
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\usepackage{subfiles}
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\usepackage{nomencl}
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\usepackage{chngcntr}
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\makenomenclature
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\usepackage{makeidx}
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\makeindex
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\counterwithout{figure}{chapter}
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\usetikzlibrary{external,calc,trees,positioning,arrows,chains,shapes.geometric,%
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decorations.pathreplacing,decorations.pathmorphing,shapes,%
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matrix,fit,shapes.symbols,backgrounds,fit}
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\captionsetup[figure]{labelformat=simple}
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\renewcommand{\figurename}{Figure}
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% Returns three nodes: The argument, and the projections of the argument on the left and right borders of the bounding box
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\newcommand{\extendnode}[1]{
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(#1)
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($(current bounding box.north east)!(#1)!(current bounding box.south east)$)
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($(current bounding box.north west)!(#1)!(current bounding box.south west)$)
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}
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\usetikzlibrary{calc,trees,positioning,arrows,chains,shapes.geometric,%
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decorations.pathreplacing,decorations.pathmorphing,shapes,%
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matrix,shapes.symbols,backgrounds,fit,intersections}
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\title{OAI EPC current development}
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\author{Sebastien ROUX\\Eurecom\\sebastien.roux@eurecom.fr}
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\definecolor{javared}{rgb}{0.6,0,0} % for strings
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\definecolor{javagreen}{rgb}{0.25,0.5,0.35} % comments
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\definecolor{ckeyw}{rgb}{0,0,0.8} % keywords
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\definecolor{ccomment}{rgb}{0.6,0.6,0.6} % javadoc
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\lstset{
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language=C,
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basicstyle=\ttfamily,
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keywordstyle=\color{ckeyw}\bfseries,
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stringstyle=\color{javared},
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commentstyle=\color{ccomment},
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morecomment=[s][\color{ccomment}]{/**}{*/},
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numbers=left,
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numberstyle=\tiny\color{black},
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stepnumber=1,
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numbersep=10pt,
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tabsize=4,
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showspaces=false,
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showstringspaces=false,
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breaklines
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}
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\tikzset{
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table nodes/.style={
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rectangle,
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rounded corners=0.6mm,
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draw=black,
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align=center,
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minimum height=7mm,
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minimum width=22mm,
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text depth=0.5ex,
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text height=2ex,
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% inner xsep=0pt,
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outer sep=0pt,
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},
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table/.style={
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matrix of nodes,
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% row sep=-\pgflinewidth,
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% column sep=-\pgflinewidth,
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rectangle,
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nodes={
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table nodes
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execute at empty cell={\node[draw=none]{};}
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cps/.style={
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draw=black,
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fill=blue!20,
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rounded corners=0.6mm,
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},
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ups/.style={
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draw=black,
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fill=yellow!30,
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rounded corners=0.6mm,
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},
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stdlinux/.style={
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draw=black,
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fill=green!10,
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rounded corners=0.6mm,
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rect/.style={
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rectangle,
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draw,
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schritt/.style={
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draw,
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inner xsep=2em,
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t0/.style={draw,fill=blue!20},
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t1/.style={draw,fill=blue!40},
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background/.style={
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draw,
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fill=yellow!30,
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align=center,
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dashed,
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background2/.style={
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draw,
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fill=green!15,
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align=center,
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},
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connector/.style={
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-latex,
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font=\scriptsize
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},
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rectangle connector/.style={
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connector,
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to path={(\tikztostart) -| (\tikztotarget) },
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pos=0.5
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},
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rectangle connector/.default=-2cm,
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straight connector/.style={
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connector,
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to path=--(\tikztotarget) \tikztonodes
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},
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queue/.style={
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draw,
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fill=yellow!30,
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cylinder,
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aspect=0.7,
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minimum height=1cm,
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minimum width=0.7cm
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},
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}
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\renewcommand{\nomname}{List of Abbreviations}
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\renewcommand{\thefigure}{\Alph{figure}}
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\begin{document}
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\maketitle
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\tableofcontents
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\printnomenclature[2cm]
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\chapter*{MME and S+P-Gateway} \stepcounter{chapter}
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\addcontentsline{toc}{chapter}{MME and S+P-Gateway}
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% \nomenclature{MME}{Mobility Management Entity}
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% \nomenclature{S-GW}{Serving Gateway}
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% \nomenclature{P-GW}{PDN Gateway}
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\begin{figure}[H]
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\begin{center}
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\begin{tikzpicture}
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\tikzstyle{every node}=[font=\footnotesize]
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\matrix (table) [row sep=0.5cm, column sep={3.2cm,between origins}, table,text width=3mm,name=table] {
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& & &\\
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& & &\\
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& & &\\
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& & &\\
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& & &\\
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};
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\node(MMEAPP)[cps,draw,fit=(table-1-1)(table-1-2),table nodes]{MME Application};
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\node(SPGW)[cps,draw,fit=(table-1-3)(table-1-4),table nodes]{S+P-GW Application};
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\node(NAS)[cps,draw,fit=(table-2-2),table nodes]{NAS};
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\node(S6A)[dashed,cps,draw,fit=(table-3-1),table nodes]{S6a/Diameter};
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\node(S1AP)[cps,draw,fit=(table-3-2),table nodes]{S1-MME/S1AP};
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\node(S1U)[ups,draw,fit=(table-3-3),table nodes]{S1-U/GTPU};
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\node(SGI)[dashed,ups,draw,fit=(table-3-4),table nodes]{SGi};
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\node(SCTP)[stdlinux,draw,fit=(table-4-1)(table-4-2),table nodes]{SCTP};
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\node(UDP)[stdlinux,draw,fit=(table-4-3),table nodes]{UDP};
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\node(IP)[stdlinux,draw,fit=(table-5-1)(table-5-2)(table-5-3)(table-5-4),table nodes]{IP};
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\draw[<->, dashed, draw=red] (MMEAPP) -- node(arrow1)[above, align=center]{S11}(SPGW);
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\draw[<-,dashed] (S1U) -- (SPGW.south-|S1U);
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\draw[<-,dashed] (SGI) -- (SPGW.south-|SGI);
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\draw[-] (S6A) -- (MMEAPP.south-|S6A);
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\draw[-] (NAS) -- (MMEAPP.south-|NAS);
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\draw[-] (S1AP) -- (NAS);
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\draw[-] (S1U) -- (SGI);
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\draw[-] (S1U) -- (UDP);
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\draw[-] (S1AP) -- (SCTP.north-|S1AP);
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\draw[-] (S6A) -- (SCTP.north-|S6A);
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\draw[-] (SCTP) -- (IP.north-|SCTP);
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\draw[-] (UDP) -- (IP.north-|UDP);
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\draw[-] (SGI) -- (IP.north-|SGI);
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\draw[-] (MMEAPP.south) |- (S1AP.west);
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\draw($(table.north west) + (-2mm,1mm)$) rectangle ($(table.south east) + (2mm,-1mm)$);
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\node[cps, minimum width=5mm,minimum height=5mm,below=of IP.south west,anchor=west](l1){};
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\node[right=2mm of l1](ct1) {Control Plane};
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\node[ups,minimum width=5mm,minimum height=5mm,below=0.3cm of l1](l2){};
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\node[below=0.3cm of ct1, right=2mm of l2](ct2) {User Plane};
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\node[stdlinux,minimum width=5mm,minimum height=5mm,below=0.3cm of l2](l3){};
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\node[below=0.3cm of ct2, right=2mm of l3](ct3) {Linux IP Stack};
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\draw[minimum width=5mm,minimum height=5mm,below=0.3cm of l3,<->,dashed, draw=red]
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($(l3.south west) - (0,0.55cm)$) -- node(l4){} ($(l3.south east) - (0,0.55cm)$);
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\node[right=2mm of l4.north east](ct4) {Abstraction link};
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\draw[minimum width=5mm,minimum height=5mm,below=0.3cm of l4,->,dashed]
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($(l4.south west) - (0,0.25cm)$) -- node(l5){} ($(l4.south east) - (0,0.25cm)$);
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\node[right=2mm of l5.north east](ct5) {Control};
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\node[draw,fit=(ct1)(l1)(ct2)(l2)(ct3)(l3)(ct4)(l4)(ct5)(l5)] {};
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\end{tikzpicture}
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\caption{MME and S+P-GW architecture} \label{fig:MMEoverall}
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\end{center}
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\end{figure}
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Figure \ref{fig:MMEoverall} shows the targeted implementation of Eurecom
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EPC.
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\chapter*{S1AP layer} \stepcounter{chapter}
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\addcontentsline{toc}{chapter}{S1AP layer}
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\nomenclature{S1AP}{S1 Application Protocol}S1AP layer relies on
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\nomenclature{ASN.1}{Abstract Syntax Notation.1}ASN.1 messages
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description. Generating C code from the specification
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implies three steps:
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\begin{enumerate}
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\item Modify .asn files to match tools limitation.
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\item Generate \nomenclature{IE}{Informations Elements}IEs with the help of the asn1c free tool.
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\item Use the provided script which generates \nomenclature{PDU}{Protocol Data Unit}PDU codec\footnote{Encode/Decode}.
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\end{enumerate}
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\chapter*{Inter-task interface} \stepcounter{chapter}
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\addcontentsline{toc}{chapter}{Inter-task interface}
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\section{Concurrency}
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Code divided in layers should be able to be executed in parallel to use the full
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\nomenclature{CPU}{Control Processing Unit}CPUs power. We can achieve better performance
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by using some mechanisms that runs part of code in parallel on UNIX platforms:
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\begin{itemize}
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\item Multi-process: no link between processes, usage of sockets or pipes is mandatory.
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\item Forks: code is duplicated and data are stored in different spaces.
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\item Threads: only code is duplicated, data space is shared between processes
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\end{itemize}
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Data synchronization is the first issue to think about when using such mechanisms.
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\section{Overall description}
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A single \nomenclature{API}{Application Programming Interface}API
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(called ITTI\footnote{InTer-Task Interface}) is used to manage messages
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exchanged between the tasks which are running on separate threads.
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This will lead in better usage of multi-core environments.
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\begin{figure}[h]
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\begin{center}
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\begin{tikzpicture}
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\node[](t1) { Task A };
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\node[below=of t1,yshift=7mm,font=\tiny](s1) { send msg to task };
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\node[queue,rotate=90,below=of t1.south,anchor=top](c1) {};
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\node[right=of t1,xshift=15mm](t2) { Task B };
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\node[below=of t2,yshift=7mm,font=\tiny](r2) { recv msg from task };
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\node[queue,rotate=90,below=of t2.south,anchor=top](c2) {};
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\node[dashed,fit=(c1)(t1)(s1),draw](T1){};
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\node[dashed,fit=(c2)(t2)(r2),draw](T2){};
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\node[draw](ITTI) at ($(T1)!0.5!(T2) + (0, -2.3)$){ITTI interface};
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\draw[->] (T1) |- (ITTI);
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\draw[->] (ITTI.east) -| (c2.bottom);
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\draw[->] (c2.east) -- (r2);
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\node[queue,rotate=90,minimum width=5mm,minimum height=7mm,right=of c2,anchor=top,yshift=-15mm](c3) {};
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\node[dashed,rectangle,minimum width=5mm,minimum height=5mm,draw,below=7mm of c3,anchor=east](c4) {};
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\node[right=4mm of c3.shape center](x3){Message queue};
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\node[right=4mm of c4.center](x4){Thread};
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\node[draw,fit=(c3)(x3)(x4)(c4)](T4){};
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\end{tikzpicture}
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\caption{Overall process} \label{fig:Overall process}
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\end{center}
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\end{figure}
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Figure \ref{fig:Overall process} describes the basic fonctionnement of the inter-task interface.
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A message sent from
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Task A is en-queued to the message queue belonging to the target task. Note that
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tasks can send messages to themselves. Another API (See Figure \ref{fig:Broadcasting process}) defines broadcast messaging
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where any task can send a broadcast message to every other task.
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\begin{figure}[H]
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\begin{center}
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\begin{tikzpicture}
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\node[](t1) { Task A };
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\node[below=of t1,yshift=7mm,font=\tiny](s1) { send broadcast msg };
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\node[queue,rotate=90,below=of t1.south,anchor=top](c1) {};
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\node[right=of t1,xshift=35mm](t2) { Task B };
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\node[below=of t2,yshift=7mm,font=\tiny](r2) { recv msg from task };
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\node[queue,rotate=90,below=of t2.south,anchor=top](c2) {};
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\node[right=of t2,xshift=15mm](tn) { Task N };
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\node[below=of tn,yshift=7mm,font=\tiny](rn) { recv msg from task };
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\node[queue,rotate=90,below=of tn.south,anchor=top](cn) {};
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\node[dashed,fit=(c1)(t1)(s1),draw](T1){};
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\node[dashed,fit=(c2)(t2)(r2),draw](T2){};
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\node[dashed,fit=(cn)(tn)(rn),draw](TN){};
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\node[](ITTI) at ($(T2)!0.5!(TN)$){...};
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\node[draw](ITTI) at ($(T1)!0.5!(T2) + (0, -2.3)$){ITTI interface};
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\draw[->] (T1) |- (ITTI);
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\draw[->] (ITTI.east) -| (c2.bottom);
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\draw[->] (ITTI.east) -| (cn.bottom);
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\draw[->] (c2.east) -- (r2);
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\draw[->] (cn.east) -- (rn);
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\node[queue,rotate=90,minimum width=5mm,minimum height=7mm,below=23mm of T1](c3) {};
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\node[dashed,rectangle,minimum width=5mm,minimum height=5mm,draw,below=7mm of c3,anchor=east](c4) {};
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\node[right=4mm of c3.shape center](x3){Message queue};
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\node[right=4mm of c4.center](x4){Thread};
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\node[draw,fit=(c3)(x3)(x4)(c4)](T4){};
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\end{tikzpicture}
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\caption{Broadcasting process} \label{fig:Broadcasting process}
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\end{center}
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\end{figure}
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Once a task received a new message and if the task is in sleep mode (i.e. not handling
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any message), the task is waken up and the message is de-queued. We can imagine a limit
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in number of parallel tasks, for example N+1 CPU's. Architectures using hyper-threading
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mechanism can have this value extended to 2 x CPU's.
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Every task is running in a separated pthread, awaiting for new messages to handle.
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\section{Signals from kernel}
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Handling of signals from kernel is the more critical part as a signal can be raised
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at any moment and will interrupt one of the running thread. Used signals should be restricted
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|
||||||
to a single task that will handle them (using the POSIX sigmask function) . Moreover, it isn't
|
|
||||||
thread-safe to use mutexes inside a signal handler, a synchronization flag should be used to
|
|
||||||
notify the signal handler task. This task will then send the appropriate message
|
|
||||||
to the right task. For example, handling of signals can be done in the main thread or by a background task
|
|
||||||
scheduled periodically.
|
|
||||||
To overcome these issues, sigtimedwait and sigwaitinfo API functions can be used
|
|
||||||
to wait for a signal to happen. Signals will be received in the thread context, as far as
|
|
||||||
other threads block these signals.
|
|
||||||
|
|
||||||
\section{Priority handling}
|
|
||||||
|
|
||||||
Usage of message prioritization enables tasks to send critical messages with a faster
|
|
||||||
delivery time regarding other messages en-queued for the target task.
|
|
||||||
For now only seven priority levels can be applied when defining tasks:
|
|
||||||
\begin{itemize}
|
|
||||||
\item TASK\_PRIORITY\_MAX
|
|
||||||
\item TASK\_PRIORITY\_MAX\_LEAST
|
|
||||||
\item TASK\_PRIORITY\_MED\_PLUS
|
|
||||||
\item TASK\_PRIORITY\_MED
|
|
||||||
\item TASK\_PRIORITY\_MED\_LEAST
|
|
||||||
\item TASK\_PRIORITY\_MIN\_PLUS
|
|
||||||
\item TASK\_PRIORITY\_MIN
|
|
||||||
\end{itemize}
|
|
||||||
For now message priority does not involve any suitable scheduler: every time a message is de-queued,
|
|
||||||
message priority of other messages is incremented by one.
|
|
||||||
|
|
||||||
\section{Message scheduling}
|
|
||||||
Currently, there is no software limit on the maximum number of threads executed in parallel.
|
|
||||||
When a task sends a message, it is en-queued in the right message queue, belonging to
|
|
||||||
the target task. The queue is a double-linked list. A mutex prevents other tasks
|
|
||||||
from modifying this queue while a task is en-queueing or removing a message.
|
|
||||||
|
|
||||||
\section{Message definition}
|
|
||||||
Messages are defined using a single macro that adds the message to the ids enumeration
|
|
||||||
and maps data of the message to the union of messages.
|
|
||||||
\begin{lstlisting}
|
|
||||||
MESSAGE_DEF(S1AP_SCTP_NEW_MESSAGE_IND, TASK_PRIORITY_MED, S1apSctpNewMessageInd s1apSctpNewMessageInd)
|
|
||||||
\end{lstlisting}
|
|
||||||
and the associated data:
|
|
||||||
\begin{lstlisting}
|
|
||||||
typedef struct {
|
|
||||||
uint8_t *buffer; ///< SCTP buffer
|
|
||||||
uint32_t bufLen; ///< SCTP buffer length
|
|
||||||
int32_t assocId; ///< SCTP physical association ID
|
|
||||||
uint8_t stream; ///< Stream number on which data had been received
|
|
||||||
uint16_t instreams; ///< Number of input streams for the SCTP connection between peers
|
|
||||||
uint16_t outstreams; ///< Number of output streams for the SCTP connection between peers
|
|
||||||
} S1apSctpNewMessageInd;
|
|
||||||
\end{lstlisting}
|
|
||||||
\section{Task message handling}
|
|
||||||
\begin{lstlisting}
|
|
||||||
void* s1ap_mme_thread(void *args) {
|
|
||||||
while(1) {
|
|
||||||
/* Trying to fetch a message from the message queue.
|
|
||||||
* If the queue is empty, this function will block till a
|
|
||||||
* message is sent to the task.
|
|
||||||
*/
|
|
||||||
receive_msg(TASK_S1AP, &receivedMessage);
|
|
||||||
assert(receivedMessage != NULL);
|
|
||||||
switch(receivedMessage->messageId) {
|
|
||||||
case S1AP_SCTP_NEW_MESSAGE_IND:
|
|
||||||
{
|
|
||||||
//Some processing
|
|
||||||
} break;
|
|
||||||
default:
|
|
||||||
{
|
|
||||||
S1AP_DEBUG("Unkwnon message ID %d\n", receivedMessage->messageId);
|
|
||||||
} break;
|
|
||||||
}
|
|
||||||
free(receivedMessage);
|
|
||||||
receivedMessage = NULL;
|
|
||||||
}
|
|
||||||
return NULL;
|
|
||||||
}
|
|
||||||
\end{lstlisting}
|
|
||||||
\section{Messages logging}
|
|
||||||
\begin{figure}[H]
|
|
||||||
\begin{center}
|
|
||||||
\begin{tikzpicture}
|
|
||||||
\node[](p1) { Process };
|
|
||||||
\node[below=5mm of p1](i1) { ITTI };
|
|
||||||
\node[queue,right=of i1,rotate=90,anchor=base](q1) {};
|
|
||||||
\node[draw,fit=(i1)(q1)](s1) { };
|
|
||||||
\node[fit=(p1)(i1)(q1)(s1),draw](T1){};
|
|
||||||
\node[queue,fill=red!30,right=of s1.east,yshift=-5mm](c1) { TCP socket };
|
|
||||||
\node[right=of c1](r1){ Remote host n };
|
|
||||||
\node[fit=(r1),draw](R2){};
|
|
||||||
\node[queue,fill=red!30,right=of s1.east,yshift=5mm](c2) { TCP socket };
|
|
||||||
\node[right=of c2](r1){ Remote host 1 };
|
|
||||||
\node[fit=(r1),draw](R1){};
|
|
||||||
\draw[-] (q1.base) -- ++ (1,0) -| ++ (0,.6) -- (c2.west);
|
|
||||||
\draw[-] (c2) -- (R1);
|
|
||||||
\draw[-] (q1.base) -- ++ (1,0) -| ++ (0,-.4) -- (c1.west);
|
|
||||||
\draw[-] (c1) -- (R2);
|
|
||||||
\end{tikzpicture}
|
|
||||||
\caption{Remote debugging} \label{fig:Remote debugging}
|
|
||||||
\end{center}
|
|
||||||
\end{figure}
|
|
||||||
Logging of inter-tasks messages can be setup using an external tool that will be
|
|
||||||
connected to the ITTI. Based on an array of dumped messages, they are serialized
|
|
||||||
to produce an array of byte sent over a socket. A remote tool can then decode
|
|
||||||
messages and display fields, message number, time.\\
|
|
||||||
Additionaly, logs from standard output can be printed over the debug tool.
|
|
||||||
Multi-user debugging on only one running process can be achieved using this interface.
|
|
||||||
Messages to dump should be queued for a pure asynchronous communication between the
|
|
||||||
dump task and the remote hosts.
|
|
||||||
Another interesting feature could be to send a message to a task from an host,
|
|
||||||
allowing run-time re-configuration.
|
|
||||||
The C pre-processor can be used to generate messages definition (using
|
|
||||||
\nomenclature{XML}{Extensible Markup Language}XML templates
|
|
||||||
for example).\\
|
|
||||||
\section{Limitations}
|
|
||||||
Data pointers belonging to one task should never be passed to another task.
|
|
||||||
The presented mechanism does not prevent a task from being locked. In such a case,
|
|
||||||
the blocked task will no more handle messages incoming from other tasks.
|
|
||||||
|
|
||||||
\section{Benefits}
|
|
||||||
\begin{itemize}
|
|
||||||
\item Only a single entry point between all tasks (easy inter-task communication tracking and debugging).
|
|
||||||
\item Usage of message queues enables parallelization of layers.
|
|
||||||
\item Message prioritization and scheduling.
|
|
||||||
\item Protection of data between threads is done by the API at an higher level.
|
|
||||||
\end{itemize}
|
|
||||||
|
|
||||||
\section{To do}
|
|
||||||
\begin{itemize}
|
|
||||||
\item Implement a priority based scheduler. Currently the queue of messages works as a FIFO.
|
|
||||||
\item Limit the number of tasks thread that can be run in parallel
|
|
||||||
\end{itemize}
|
|
||||||
|
|
||||||
\chapter*{Signal API} \stepcounter{chapter}
|
|
||||||
\addcontentsline{toc}{chapter}{Signal API}
|
|
||||||
|
|
||||||
On LINUX platforms, processes will receive signals comming from Kernel.
|
|
||||||
A single blocking entry point handles all used signals that are requested by the
|
|
||||||
MME. The main application thread is reserved to signal handling as this thread will
|
|
||||||
be blocked till a new signal is ready for handling.\\
|
|
||||||
Using this method prevents threads from being interrupted by signals handler which
|
|
||||||
can interrupt the thread at any time and as a consequence create some misbehaving
|
|
||||||
in threads contexts.
|
|
||||||
Following is a sample list of signals handled:
|
|
||||||
\begin{itemize}
|
|
||||||
\item SIGABRT This is signal is sent to the process when abort() function is called
|
|
||||||
within the process and kill the process. Process can for example display the stack
|
|
||||||
once this signal is received.
|
|
||||||
\item SIGRTMIN This signal is used by the timer API and is raised everytime a
|
|
||||||
timer has expired.
|
|
||||||
\end{itemize}
|
|
||||||
Till now there is no way for tasks to request a new signal.
|
|
||||||
|
|
||||||
\chapter*{Timer API} \stepcounter{chapter}
|
|
||||||
\addcontentsline{toc}{chapter}{Timer API}
|
|
||||||
|
|
||||||
Timer API doesn't consist of a task (i.e. tasks cannot send messages to it).
|
|
||||||
Handling of UNIX signal associated to the timers is a Real-time signal with an id (SIGRTMIN)
|
|
||||||
depending on the platform. Management of this signal is done by the signal interface
|
|
||||||
and developpers should not care about handling timer signals incoming from Kernel.
|
|
||||||
Once a timer has expired the task which has requested it will receive the TIMER\_HAS\_EXPIRED
|
|
||||||
signal.
|
|
||||||
Note that timer\_id is of type long and thus its size is platform specific.
|
|
||||||
|
|
||||||
\section{Timer types}
|
|
||||||
|
|
||||||
\begin{itemize}
|
|
||||||
\item TIMER\_ONE\_SHOT After expiry and its associated signal, the timer is removed.
|
|
||||||
\item TIMER\_PERIODIC The timer is automatically reloaded on each expiry while the task
|
|
||||||
which has setup this timer doesn't cancel it.
|
|
||||||
\end{itemize}
|
|
||||||
|
|
||||||
\section{Requesting a new signal}
|
|
||||||
Any task can request a new signal by invoking the following API:
|
|
||||||
\begin{lstlisting}
|
|
||||||
int timer_setup(
|
|
||||||
uint32_t interval_sec,
|
|
||||||
uint32_t interval_us,
|
|
||||||
task_id_t task_id,
|
|
||||||
timer_type_t type,
|
|
||||||
long *timer_id);
|
|
||||||
\end{lstlisting}
|
|
||||||
|
|
||||||
Note that timer id is a unique identifier to distinguish timers.
|
|
||||||
|
|
||||||
\section{Disable and remove a timer}
|
|
||||||
|
|
||||||
Disable and remove the timer referenced by timer\_id.
|
|
||||||
\begin{lstlisting}
|
|
||||||
int timer_remove(long timer_id);
|
|
||||||
\end{lstlisting}
|
|
||||||
|
|
||||||
\section{Timer signal expiry}
|
|
||||||
|
|
||||||
Once the signal dispatcher receives the SIGRTMIN signal, a new signal is sent
|
|
||||||
to the task which has requested the timer. Contrary to signal request, timer
|
|
||||||
expiry notification is achieved using the intertask mechanism.
|
|
||||||
The signal data associated to this event follows:
|
|
||||||
\begin{lstlisting}
|
|
||||||
typedef struct {
|
|
||||||
long timer_id;
|
|
||||||
} timer_has_expired_t;
|
|
||||||
\end{lstlisting}
|
|
||||||
|
|
||||||
\chapter*{Compiling core EPC} \stepcounter{chapter}
|
|
||||||
\addcontentsline{toc}{chapter}{Compiling core EPC}
|
|
||||||
|
|
||||||
The core EPC software has been tested on Ubuntu 12.04LTS x86 and ia64.
|
|
||||||
Before compiling the core EPC, some packages should be installed on the platform.
|
|
||||||
|
|
||||||
\section{Dependencies}
|
|
||||||
|
|
||||||
\begin{itemize}
|
|
||||||
\item libsctp-dev
|
|
||||||
\item libpthread-dev
|
|
||||||
\item automake and autoconf
|
|
||||||
\item libtoolize
|
|
||||||
\item gcc, g++, make
|
|
||||||
\item flex and bison
|
|
||||||
\item openssl-dev
|
|
||||||
\item asn1c (see section \ref{sec:asn1c})
|
|
||||||
\item freediameter (see section \ref{sec:freediameter}) and gnutls 3.1.0
|
|
||||||
(see section \ref{sec:gnutls})
|
|
||||||
\end{itemize}
|
|
||||||
Command-line to install the required packages:
|
|
||||||
\begin{lstlisting}
|
|
||||||
sudo apt-get install cmake make gcc flex bison \
|
|
||||||
libsctp1 libsctp-dev libidn2-0-dev libidn11-dev \
|
|
||||||
libmysqlclient-dev libxml2-dev swig python-dev \
|
|
||||||
cmake-curses-gui valgrind guile-2.0-dev \
|
|
||||||
libgmp-dev libgcrypt11-dev gdb unzip \
|
|
||||||
libtasn1-3-dev g++ autoconf automake \
|
|
||||||
openssl-dev -y
|
|
||||||
\end{lstlisting}
|
|
||||||
|
|
||||||
\subsection{ASN1c}
|
|
||||||
\label{sec:asn1c}
|
|
||||||
|
|
||||||
\subsection{gnutls}
|
|
||||||
\label{sec:gnutls}
|
|
||||||
|
|
||||||
The GNUTls library is only used by freediameter for certificate handling and as a
|
|
||||||
consequence should be installed before trying to compile the freediameter library.
|
|
||||||
\begin{lstlisting}
|
|
||||||
wget ftp://ftp.gnutls.org/gcrypt/gnutls/v3.1/gnutls-3.1.0.tar.xz
|
|
||||||
tar -xvf gnutls-3.1.0.tar.xz
|
|
||||||
cd gnutls-3.1.0/
|
|
||||||
./configure LDFLAGS='-L/usr/local/lib'
|
|
||||||
make
|
|
||||||
sudo make install
|
|
||||||
\end{lstlisting}
|
|
||||||
Note: when dependencies are installed in /usr/local instead of /usr,
|
|
||||||
LDFLAGS has to be overriden with the path to libraries when configuring the package:
|
|
||||||
LDFLAGS='-L/usr/local/lib'.
|
|
||||||
|
|
||||||
\subsection{freediameter}
|
|
||||||
\label{sec:freediameter}
|
|
||||||
Freediameter is the package that provides diameter capabilities to the MME/HSS.
|
|
||||||
On top of this stack, S6A avp dictionnary is used to enable a compliant S6A interface.
|
|
||||||
\begin{lstlisting}
|
|
||||||
wget http://www.freediameter.net/hg/freeDiameter/archive/1.1.5.tar.gz
|
|
||||||
tar -xvf 1.1.5.tar.gz
|
|
||||||
cd freeDiameter-1.1.5
|
|
||||||
patch -p1 < ../../freediameter-1.1.5.patch
|
|
||||||
mkdir build
|
|
||||||
cd build
|
|
||||||
cmake ../
|
|
||||||
make
|
|
||||||
make test
|
|
||||||
sudo make install
|
|
||||||
\end{lstlisting}
|
|
||||||
If you want ot install this package in /usr instead of /usr/local,\\
|
|
||||||
-DCMAKE\_INSTALL\_PREFIX:PATH=/usr should be passed to cmake at configuration.
|
|
||||||
|
|
||||||
\chapter*{System configuration} \stepcounter{chapter}
|
|
||||||
\addcontentsline{toc}{chapter}{System configuration}
|
|
||||||
|
|
||||||
Currently there is two ways to configure the system:
|
|
||||||
\begin{itemize}
|
|
||||||
\item Compilation configuration
|
|
||||||
\item Boot-up configuration
|
|
||||||
\end{itemize}
|
|
||||||
In the first type of configuration, the single system configuration structure
|
|
||||||
is filled in with default values that can be found in the mme\_default\_values.h
|
|
||||||
header file.\\
|
|
||||||
When Boot-up configuration is used, a configuration file is passed to the process
|
|
||||||
by using the either -c filename.conf or --conf=filename.conf. This file is then parsed
|
|
||||||
by the bison interpreter and values are replaced in the global system configuration
|
|
||||||
structure.
|
|
||||||
|
|
||||||
\section{Global MME parameters}
|
|
||||||
|
|
||||||
\subsection{Relative MME capacity}
|
|
||||||
Even though this parameter is not used by the MME for controlling the MME load
|
|
||||||
balancing within a pool (at least for now), the parameter has to be to forwarded
|
|
||||||
to the eNBs during association procedure.
|
|
||||||
This parameter is encoded on 8bits, acceptable values going from 0 to 255.
|
|
||||||
(Default value = 15)
|
|
||||||
\begin{lstlisting}
|
|
||||||
RELATIVE_CAPACITY = 10;
|
|
||||||
\end{lstlisting}
|
|
||||||
|
|
||||||
\subsection{Maximum number of UE}
|
|
||||||
\label{sec:Maximum number of UE}
|
|
||||||
This limit is present here only for debug purposes and is used to restrict
|
|
||||||
the number of served UE the MME can handle. In real network another mechanism
|
|
||||||
will trigger an MME overload for certain eNBs and will restrict certain types of
|
|
||||||
traffic. Such a mechanism would imply the Relative MME capacity.
|
|
||||||
\begin{lstlisting}
|
|
||||||
MAXUE = 100;
|
|
||||||
\end{lstlisting}
|
|
||||||
|
|
||||||
\subsection{Maximum number of eNB}
|
|
||||||
Refer to \ref{sec:Maximum number of UE}.
|
|
||||||
\begin{lstlisting}
|
|
||||||
MAXENB = 10;
|
|
||||||
\end{lstlisting}
|
|
||||||
|
|
||||||
\subsection{Tracking Area Identity}
|
|
||||||
\nomenclature{TAI}{Tracking Area Identity}TAI is the concatenation of
|
|
||||||
\nomenclature{MCC}{Mobile Country Code}MCC, \nomenclature{MNC}{Mobile Network Code}MNC and
|
|
||||||
\nomenclature{TAC}{Tracking Area Code}TAC.
|
|
||||||
The TAC uniquely identifies a PLMN within a Cell Id.
|
|
||||||
\begin{lstlisting}
|
|
||||||
PLMN = mcc.mnc:tac;
|
|
||||||
\end{lstlisting}
|
|
||||||
Multiple values can be given using a comma separator. Example:
|
|
||||||
\begin{lstlisting}
|
|
||||||
PLMN = 208.38:0,209.130:4,208.35:8;
|
|
||||||
\end{lstlisting}
|
|
||||||
|
|
||||||
\subsection{MME Code}
|
|
||||||
A list of a maximum of 256 values can be provided.
|
|
||||||
\nomenclature{MMEC}{MME Code}MME Code is encoded on 8 bits,
|
|
||||||
so acceptable range is: 0 to 255.
|
|
||||||
Example:
|
|
||||||
\begin{lstlisting}
|
|
||||||
MME_CODE = 30,56,1,8;
|
|
||||||
\end{lstlisting}
|
|
||||||
|
|
||||||
\subsection{MME Group Id}
|
|
||||||
A list of a maximum of 65356 values can be provided.
|
|
||||||
\nomenclature{MMEGID}{MME Group Id}MME Group Id is encoded on 16 bits,
|
|
||||||
so acceptable range is: 0 to 65535.
|
|
||||||
Example:
|
|
||||||
\begin{lstlisting}
|
|
||||||
MME_GID = 3,4,5,30,8,9,50021;
|
|
||||||
\end{lstlisting}
|
|
||||||
|
|
||||||
\section{Intertask parameters}
|
|
||||||
\subsection{Queue size per task}
|
|
||||||
To restrict the number of messages in queues or to detect a possible MME overload,
|
|
||||||
an upper bound for the queue size can be defined like this:
|
|
||||||
\begin{lstlisting}
|
|
||||||
ITTI_QUEUE_SIZE = 2000000;
|
|
||||||
\end{lstlisting}
|
|
||||||
This parameter is expressed in bytes. Note that all messages exchanged by tasks
|
|
||||||
have the same size.
|
|
||||||
|
|
||||||
\section{SCTP parameters}
|
|
||||||
\subsection{IN/OUT streams number}
|
|
||||||
The number of input/output streams can be configured to limit the number of streams
|
|
||||||
used for UE-associated signalling. Note that stream with id = 0 is reserved for
|
|
||||||
non-UE associated signalling. At least two streams should be used by the MME.
|
|
||||||
(Default value = 64/64 streams)
|
|
||||||
\begin{lstlisting}
|
|
||||||
SCTP_INSTREAMS = 32;
|
|
||||||
SCTP_OUTSTREAMS = 32;
|
|
||||||
\end{lstlisting}
|
|
||||||
|
|
||||||
\section{S1AP parameters}
|
|
||||||
\subsection{Outcome timer}
|
|
||||||
Once an outcome is sent from MME to eNB, the MME locally starts a timer to abort
|
|
||||||
the procedure and release UE contexts if the expected answer to this outcome is not
|
|
||||||
received at the expiry of this timer.\\
|
|
||||||
This timer is expressed in seconds. (Default value = 5 seconds)
|
|
||||||
\begin{lstlisting}
|
|
||||||
S1AP_OUTCOME_TIMER = 10;
|
|
||||||
\end{lstlisting}
|
|
||||||
|
|
||||||
\section{Network interfaces parameters}
|
|
||||||
|
|
||||||
Three paramters can be tuned in the configuration file:
|
|
||||||
\begin{itemize}
|
|
||||||
\item Interface Name: The related interface will be bind to this interface name
|
|
||||||
\item IP address: Currently only IPv4 address is allowed
|
|
||||||
\item IP netwmask: Netmask for the LAN
|
|
||||||
\end{itemize}
|
|
||||||
These three paramters can be setup for five different interfaces used:
|
|
||||||
\begin{itemize}
|
|
||||||
\item SGW interface for S11
|
|
||||||
\item SGW interface for S1U/S12/S4 in user plane
|
|
||||||
\item SGW interface for S5/S8 in user plane
|
|
||||||
\item PGW interface for S5/S8
|
|
||||||
\item PGW interface for SGi
|
|
||||||
\item MME interface for S1-MME in control plane
|
|
||||||
\end{itemize}
|
|
||||||
Example of configuration:
|
|
||||||
\begin{lstlisting}
|
|
||||||
# ------- Interfaces definitions
|
|
||||||
SGW_INTERFACE_NAME_FOR_S11 = "s11sgw";
|
|
||||||
SGW_IP_ADDRESS_FOR_S11 = "192.168.10.1";
|
|
||||||
SGW_IP_NETMASK_FOR_S11 = 24;
|
|
||||||
|
|
||||||
SGW_INTERFACE_NAME_FOR_S1U_S12_S4_UP = "upsgw0";
|
|
||||||
SGW_IP_ADDRESS_FOR_S1U_S12_S4_UP = "192.168.1.1";
|
|
||||||
SGW_IP_NETMASK_FOR_S1U_S12_S4_UP = 24;
|
|
||||||
|
|
||||||
SGW_INTERFACE_NAME_FOR_S5_S8_UP = "upsgw1";
|
|
||||||
SGW_IP_ADDRESS_FOR_S5_S8_UP = "192.168.5.2";
|
|
||||||
SGW_IP_NETMASK_FOR_S5_S8_UP = 24;
|
|
||||||
|
|
||||||
PGW_INTERFACE_NAME_FOR_S5_S8 = "uppgw0";
|
|
||||||
PGW_IP_ADDRESS_FOR_S5_S8 = "192.168.5.1";
|
|
||||||
PGW_IP_NETMASK_FOR_S5_S8 = 24;
|
|
||||||
|
|
||||||
PGW_INTERFACE_NAME_FOR_SGI = "eth1";
|
|
||||||
PGW_IP_ADDR_FOR_SGI = "192.168.12.30";
|
|
||||||
PGW_IP_NETMASK_FOR_SGI = 24;
|
|
||||||
|
|
||||||
MME_INTERFACE_NAME_FOR_S1_MME = "cpmme0";
|
|
||||||
MME_IP_ADDRESS_FOR_S1_MME = "192.168.11.1";
|
|
||||||
MME_IP_NETMASK_FOR_S1_MME = 24;
|
|
||||||
\end{lstlisting}
|
|
||||||
|
|
||||||
\end{document}
|
|
||||||
@@ -1,30 +0,0 @@
|
|||||||
#/*
|
|
||||||
# * Licensed to the OpenAirInterface (OAI) Software Alliance under one or more
|
|
||||||
# * contributor license agreements. See the NOTICE file distributed with
|
|
||||||
# * this work for additional information regarding copyright ownership.
|
|
||||||
# * The OpenAirInterface Software Alliance licenses this file to You under
|
|
||||||
# * the OAI Public License, Version 1.1 (the "License"); you may not use this file
|
|
||||||
# * except in compliance with the License.
|
|
||||||
# * You may obtain a copy of the License at
|
|
||||||
# *
|
|
||||||
# * http://www.openairinterface.org/?page_id=698
|
|
||||||
# *
|
|
||||||
# * Unless required by applicable law or agreed to in writing, software
|
|
||||||
# * distributed under the License is distributed on an "AS IS" BASIS,
|
|
||||||
# * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
||||||
# * See the License for the specific language governing permissions and
|
|
||||||
# * limitations under the License.
|
|
||||||
# *-------------------------------------------------------------------------------
|
|
||||||
# * For more information about the OpenAirInterface (OAI) Software Alliance:
|
|
||||||
# * contact@openairinterface.org
|
|
||||||
# */
|
|
||||||
|
|
||||||
MYFILE=EPC
|
|
||||||
|
|
||||||
all:
|
|
||||||
pdflatex $(MYFILE).tex
|
|
||||||
pdflatex $(MYFILE).tex
|
|
||||||
makeindex $(MYFILE).nlo -s nomencl.ist -o $(MYFILE).nls
|
|
||||||
pdflatex $(MYFILE).tex
|
|
||||||
|
|
||||||
.PHONY: all
|
|
||||||
Reference in New Issue
Block a user