diff --git a/model/ccnx-l3-protocol.h b/model/ccnx-l3-protocol.h
index 86743ac..1da29b7 100644
--- a/model/ccnx-l3-protocol.h
+++ b/model/ccnx-l3-protocol.h
@@ -208,6 +208,8 @@
   Ptr<CcnxFib> m_fib; ///< \brief FIB  
   Ptr<CcnxContentStore> m_contentStore; ///< \brief Content store (for caching purposes only)
 
+  bool m_nacksEnabled;
+  
   // Time    m_bucketLeakInterval;
   // EventId m_bucketLeakEvent;
 };