diff --git a/ethernet_service.h b/ethernet_service.h
index 9478691..1886854 100644
--- a/ethernet_service.h
+++ b/ethernet_service.h
@@ -26,8 +26,13 @@
   ~EthernetService();
   void Connect();
   void Disconnect();
+
+ protected:
+  virtual std::string CalculateState() { return "idle"; }
+
  private:
   Ethernet *ethernet_;
+  const std::string type_;
   DISALLOW_COPY_AND_ASSIGN(EthernetService);
 };