diff --git a/model/ccnx-fib-impl.cc b/model/ccnx-fib-impl.cc
index e298875..10217e3 100644
--- a/model/ccnx-fib-impl.cc
+++ b/model/ccnx-fib-impl.cc
@@ -200,6 +200,12 @@
     }
 }
 
+uint32_t
+CcnxFibImpl::GetSize () const
+{
+  return super::getPolicy ().size ();
+}
+
 Ptr<const CcnxFibEntry>
 CcnxFibImpl::Begin ()
 {
diff --git a/model/ccnx-fib-impl.h b/model/ccnx-fib-impl.h
index 2768a7d..eaedeee 100644
--- a/model/ccnx-fib-impl.h
+++ b/model/ccnx-fib-impl.h
@@ -25,7 +25,7 @@
 #include "ns3/ccnx-name-components.h"
 
 #include "../utils/trie-with-policy.h"
-#include "../utils/empty-policy.h"
+#include "../utils/counting-policy.h"
 
 namespace ns3 {
 
@@ -35,7 +35,7 @@
   typedef ndnSIM::trie_with_policy<
     CcnxNameComponents,
     ndnSIM::smart_pointer_payload_traits<CcnxFibEntryImpl>,
-    ndnSIM::empty_policy_traits
+    ndnSIM::counting_policy_traits
     > trie;
 
   CcnxFibEntryImpl (const Ptr<const CcnxNameComponents> &prefix)
@@ -62,7 +62,7 @@
   typedef ndnSIM::trie_with_policy<
     CcnxNameComponents,
     ndnSIM::smart_pointer_payload_traits<CcnxFibEntryImpl>,
-    ndnSIM::empty_policy_traits
+    ndnSIM::counting_policy_traits
     > type;
 };
 
@@ -109,6 +109,9 @@
   virtual void
   Print (std::ostream &os) const;
 
+  virtual uint32_t
+  GetSize () const;
+
   virtual Ptr<const CcnxFibEntry>
   Begin ();
 
diff --git a/model/ccnx-fib.h b/model/ccnx-fib.h
index e5bda1e..eae0c65 100644
--- a/model/ccnx-fib.h
+++ b/model/ccnx-fib.h
@@ -132,6 +132,12 @@
   Print (std::ostream &os) const = 0;
 
   /**
+   * @brief Get number of entries in FIB
+   */
+  virtual uint32_t
+  GetSize () const = 0;
+
+  /**
    * @brief Return first element of FIB (no order guaranteed)
    */
   virtual Ptr<const CcnxFibEntry>
diff --git a/model/ccnx-name-components.cc b/model/ccnx-name-components.cc
index 893f7bb..a79b6bb 100644
--- a/model/ccnx-name-components.cc
+++ b/model/ccnx-name-components.cc
@@ -43,7 +43,14 @@
       Add (component.get ());
     }
 }
-  
+
+CcnxNameComponents::CcnxNameComponents (const std::string &prefix)
+{
+  istringstream is (prefix);
+  is >> *this;
+}
+
+
 const std::list<std::string> &
 CcnxNameComponents::GetComponents () const
 {
diff --git a/model/ccnx-name-components.h b/model/ccnx-name-components.h
index 1d8ef2a..eb4f8c1 100644
--- a/model/ccnx-name-components.h
+++ b/model/ccnx-name-components.h
@@ -63,6 +63,13 @@
   CcnxNameComponents (const std::list<boost::reference_wrapper<const std::string> > &components);
 
   /**
+   * @brief Constructor
+   * Creates a prefix from the string (string is parsed using operator>>)
+   * @param[in] prefix A string representation of a prefix
+   */
+  CcnxNameComponents (const std::string &prefix);
+  
+  /**
    * \brief Generic Add method
    * Appends object of type T to the list of components 
    * @param[in] value The object to be appended
diff --git a/model/ccnx-pit-entry.cc b/model/ccnx-pit-entry.cc
index dde19e7..4b075ab 100644
--- a/model/ccnx-pit-entry.cc
+++ b/model/ccnx-pit-entry.cc
@@ -41,7 +41,9 @@
                             Ptr<CcnxFibEntry> fibEntry)
   : m_container (container)
   , m_prefix (header->GetNamePtr ())
-  , m_expireTime (Simulator::Now () + header->GetInterestLifetime ())
+  , m_expireTime (Simulator::Now () + (!header->GetInterestLifetime ().IsZero ()?
+                                       header->GetInterestLifetime ():
+                                       Seconds (1.0)))
   , m_fibEntry (fibEntry)
   , m_maxRetxCount (0)
 {
diff --git a/model/ccnx-pit-impl.cc b/model/ccnx-pit-impl.cc
index 0dcfef2..f68f9dd 100644
--- a/model/ccnx-pit-impl.cc
+++ b/model/ccnx-pit-impl.cc
@@ -110,9 +110,18 @@
 {
   m_cleanEvent.Cancel ();
   if (i_time.empty ())
-    return;
+    {
+      NS_LOG_DEBUG ("No items in PIT");
+      return;
+    }
 
-  m_cleanEvent = Simulator::Schedule (i_time.begin ()->GetExpireTime (),
+  Time nextEvent = i_time.begin ()->GetExpireTime () - Simulator::Now ();
+  if (nextEvent < 0) nextEvent = Seconds (0);
+  
+  NS_LOG_DEBUG ("Schedule next cleaning in " <<
+                nextEvent.ToDouble (Time::S) << "s (at " <<
+                i_time.begin ()->GetExpireTime () << "s abs time");
+  m_cleanEvent = Simulator::Schedule (nextEvent,
                                       &CcnxPitImpl::CleanExpired, this);
 }
 
@@ -217,6 +226,12 @@
     }
 }
 
+uint32_t
+CcnxPitImpl::GetSize () const
+{
+  return super::getPolicy ().size ();
+}
+
 Ptr<CcnxPitEntry>
 CcnxPitImpl::Begin ()
 {
diff --git a/model/ccnx-pit-impl.h b/model/ccnx-pit-impl.h
index d03134c..123ed85 100644
--- a/model/ccnx-pit-impl.h
+++ b/model/ccnx-pit-impl.h
@@ -82,6 +82,9 @@
   virtual void
   Print (std::ostream &os) const;
 
+  virtual uint32_t
+  GetSize () const;
+
   virtual Ptr<CcnxPitEntry>
   Begin ();
 
diff --git a/model/ccnx-pit.h b/model/ccnx-pit.h
index 0ae3968..941b079 100644
--- a/model/ccnx-pit.h
+++ b/model/ccnx-pit.h
@@ -113,19 +113,11 @@
   virtual void
   Print (std::ostream &os) const = 0;
 
-  // template<class A,class M>
-  // void
-  // modify (A, M)
-  // {
-  //   ;
-  // }
-
-  // template<class A>
-  // void
-  // erase (A)
-  // {
-  //   ;
-  // }
+  /**
+   * @brief Get number of entries in PIT
+   */
+  virtual uint32_t
+  GetSize () const = 0;
 
   /**
    * @brief Return first element of FIB (no order guaranteed)