+
+
+ {rank=same;
+ buffer1 [label=<buffer<SUB>1</SUB>>,shape=cylinder];
+ buffer2 [label=<buffer<SUB>2</SUB>>,shape=cylinder];
+ }
+ dev1 -> buffer1 [ltail=cluster0,label="WiFi"];
+ dev2 -> buffer2 [ltail=cluster1,label="Serial"];
+ buffer1 -> dev1 [lhead=cluster0];
+ buffer2 -> dev2 [lhead=cluster1];
+