diff --git a/model/ccnx-fib.h b/model/ccnx-fib.h
index 09caab7..e5bda1e 100644
--- a/model/ccnx-fib.h
+++ b/model/ccnx-fib.h
@@ -62,7 +62,7 @@
    * \returns If entry found a valid iterator will be returned, otherwise end ()
    */
   virtual Ptr<CcnxFibEntry>
-  LongestPrefixMatch (const CcnxInterestHeader &interest) const = 0;
+  LongestPrefixMatch (const CcnxInterestHeader &interest) = 0;
   
   /**
    * \brief Add or update FIB entry