Add graph for standard communication

doc/graphviz/test.dot

@@ -1,3 +0,0 @@
-digraph G {
-    Hello->World;
-}

doc/graphviz/v6-v4-standard.dot

@@ -0,0 +1,22 @@
+graph G {
+    node [ shape="box"];
+
+
+    v6host [ label="IPv6 only host"];
+    v4host [ label="IPv4 only host"];
+
+    switch1 [ label="Network Switch", shape="oval" ];
+    switch2 [ label="Network Switch", shape="oval" ];
+
+    nat64gw [ label="NAT64 translator", rank=max ];
+
+
+    v6host--switch1;
+    v4host--switch2;
+
+    switch1--nat64gw;
+    switch2--nat64gw;
+
+
+
+}