diff --git a/include/ccnx-tunnel.h b/include/ccnx-tunnel.h
index 732370d..0525458 100644
--- a/include/ccnx-tunnel.h
+++ b/include/ccnx-tunnel.h
@@ -85,7 +85,7 @@
 class TunnelClosure : public Closure
 {
 public:
-  TunnelClosure(int retry, const DataCallback &dataCallback, const TimeoutCallback &timeoutCallback, CcnxTunnel *tunnel, const Name &originalInterest);
+  TunnelClosure(int retry, const DataCallback &dataCallback, CcnxTunnel *tunnel, const Name &originalInterest, const TimeoutCallback &timeoutCallback = TimeoutCallback());
 
   TunnelClosure(const Closure *closure, CcnxTunnel *tunnel, const Name &originalInterest);