-tap1 = add_tap(ec, "192.168.3.1", 24, "192.168.3.2", h1_node)
-tap2 = add_tap(ec, "192.168.3.3", 24, "192.168.3.4", h2_node)
-tap3 = add_tap(ec, "192.168.3.5", 24, "192.168.3.6", h3_node)
+tap1 = add_tap(ec, "192.168.3.1", "24", "192.168.3.2", h1_node)
+tap2 = add_tap(ec, "192.168.3.3", "24", "192.168.3.4", h2_node)
+tap3 = add_tap(ec, "192.168.3.5", "24", "192.168.3.6", h3_node)