[Tex/LaTex] Tikz: connect two nodes

Question

I have many nodes and want to connect two of them, but in such way that the path is not scratch off nodes, which are between these two like in the example below (I want to connect L_0 and R_0):

To create this path I used following command:

\path [line,dashed] (l0) edge [] node {} (r0);

Answer 1

Like this?

\documentclass[tikz]{standalone}
\usetikzlibrary{positioning}
\begin{document}
  \begin{tikzpicture}
    \node (a) {a};
    \node[right=1cm of a] (b) {B};
    \node[right=1cm of b] (c) {C};
    \node[right=1cm of c] (d) {D};
    \node[right=1cm of d] (e) {E};
    \node[right=1cm of e] (f) {F};
    \draw [dashed] (a) to[bend left] node {} (f);
    \draw [red,dashed] (a) -- ++(0,5mm) -| node {} (f);
  \end{tikzpicture}
\end{document}