diff --git a/ndn-cpp/transport/Transport.cpp b/ndn-cpp/transport/Transport.cpp
index 4d6024c..0fa97bc 100644
--- a/ndn-cpp/transport/Transport.cpp
+++ b/ndn-cpp/transport/Transport.cpp
@@ -15,7 +15,7 @@
   throw logic_error("unimplemented");
 }
   
-void Transport::send(unsigned char *data, unsigned int dataLength)
+void Transport::send(const unsigned char *data, unsigned int dataLength)
 {
   throw logic_error("unimplemented");
 }