\begin{tikzpicture}[x=1cm,y=1cm,font=\small,>=Latex,
 v/.style={circle,fill=black,inner sep=1.8pt},
 landmark/.style={circle,fill=orange!85!black,inner sep=2.5pt},
 route/.style={blue!75!black,thick},
 other/.style={black!65,densely dashed,thick}]
\node at (3.2,4.05) {(a) Sharing the farther endpoint};
\node[v,label=below left:\(i\)] (i) at (.3,0) {};
\node[v,label=below right:\(j\)] (j) at (5.9,0) {};
\node[v,label=above:\(u\)] (u) at (5.9,3.2) {};
\coordinate (el) at (2.05,0);
\coordinate (er) at (2.6,0);
\draw[black!30] (i)--(j)--(u)--(i);
\node[landmark,label=left:\(x_{ju}(t)\)] (x) at (5.9,1.55) {};
\draw[route,->] (er)--(j)--(x);
\draw[other,->] (el)--(i)--(u)--(x);
\draw[blue!85!black,line width=2.4pt] (el)--(er)
  node[midway,below=6pt] {\(e\)};
\node[below=4pt] at (1.13,0) {\(a\)};
\node[below=4pt] at (4.25,0) {\(b\)};
\node[right=4pt] at (5.9,.77) {\(t\)};
\node[right=4pt] at (5.9,2.4) {\(L-t\)};
\node[fill=white,inner sep=2pt] at (2.65,1.7) {\(L\)};
\node at (3.2,-1) {via \(j\): \(b+t\)};
\node at (3.2,-1.58) {via \(i,u\): \(a+L+(L-t)\)};
\node at (11.15,4.05) {(b) Disjoint support};
\node[v,label=below left:\(i\)] (di) at (8.05,0) {};
\node[v,label=below right:\(j\)] (dj) at (13.9,0) {};
\node[v,label=above:\(u\)] (du) at (8.7,3.2) {};
\node[v,label=above:\(v\)] (dv) at (13.9,3.2) {};
\coordinate (del) at (10.4,0);
\coordinate (der) at (10.95,0);
\draw[black!30] (di)--(dj) (di)--(du)--(dv)--(di);
\node[landmark,label=below:\(x_{uv}(t)\)] (dx) at (11,3.2) {};
\draw[route] (del)--(di);
\draw[route,->] (di)--(du)--(dx);
\draw[other,->] (di)--(dv)--(dx);
\draw[blue!85!black,line width=2.4pt] (del)--(der)
  node[midway,below=6pt] {\(e\)};
\node[below=4pt] at (9.22,0) {\(a\)};
\node[below=4pt] at (12.43,0) {\(b\)};
\node[left=4pt] at (8.38,1.6) {\(L\)};
\node[fill=white,inner sep=2pt] at (10.43,1.35) {\(L\)};
\node[above=4pt] at (9.85,3.2) {\(t\)};
\node[above=4pt] at (12.45,3.2) {\(L-t\)};
\node at (11.15,-1) {via \(u\): \(a+L+t\)};
\node at (11.15,-1.58) {via \(v\): \(a+L+(L-t)\)};
\end{tikzpicture}