diff --git a/ndn-cpp/face.hpp b/ndn-cpp/face.hpp
index c646dab..372c908 100644
--- a/ndn-cpp/face.hpp
+++ b/ndn-cpp/face.hpp
@@ -54,7 +54,7 @@
   
   unsigned short getPort() const { return port_; }
   
-  ptr_lib::shared_ptr<Transport> &getTransport() { return transport_; }
+  const ptr_lib::shared_ptr<Transport> &getTransport() { return transport_; }
   
   virtual void onReceivedElement(unsigned char *element, unsigned int elementLength);