diff --git a/model/pit/custom-policies/serialized-size-policy.h b/model/pit/custom-policies/serialized-size-policy.h
index 7cfb506..61f6306 100644
--- a/model/pit/custom-policies/serialized-size-policy.h
+++ b/model/pit/custom-policies/serialized-size-policy.h
@@ -96,7 +96,14 @@
         current_space_used_ -= get_size (item);
         policy_container::erase (*item);
 
-        get_order (item) = item->payload ()->GetInterest ()->GetSerializedSize ();
+        if (item->payload ()->GetInterest ()->GetWire ())
+          {
+            get_order (item) = item->payload ()->GetInterest ()->GetWire ()->GetSize ();
+          }
+        else
+          {
+            get_order (item) = 0;
+          }
         current_space_used_ += get_size (item); // this operation can violate policy constraint, so in some case
                                                 // it may be necessary to remove some other element
         policy_container::insert (*item);
@@ -105,7 +112,11 @@
       inline bool
       insert (typename parent_trie::iterator item)
       {
-        uint32_t interestSize = item->payload ()->GetInterest ()->GetSerializedSize ();
+        uint32_t interestSize = 0;
+        if (item->payload ()->GetInterest ()->GetWire ())
+          {
+            interestSize = item->payload ()->GetInterest ()->GetWire ()->GetSize ();
+          }
 
         // can't use logging here
         NS_LOG_DEBUG ("Number of entries: " << policy_container::size ()
diff --git a/model/pit/ndn-pit-entry.cc b/model/pit/ndn-pit-entry.cc
index 906fcdd..1908dd0 100644
--- a/model/pit/ndn-pit-entry.cc
+++ b/model/pit/ndn-pit-entry.cc
@@ -25,6 +25,7 @@
 #include "ns3/ndn-name.h"
 #include "ns3/ndn-interest.h"
 
+#include "ns3/packet.h"
 #include "ns3/simulator.h"
 #include "ns3/log.h"
 
diff --git a/model/pit/ndn-pit.cc b/model/pit/ndn-pit.cc
index ea84496..079cf3f 100644
--- a/model/pit/ndn-pit.cc
+++ b/model/pit/ndn-pit.cc
@@ -27,6 +27,7 @@
 #include "ns3/nstime.h"
 #include "ns3/uinteger.h"
 #include "ns3/simulator.h"
+#include "ns3/packet.h"
 
 #include <boost/lambda/bind.hpp>
 #include <boost/lambda/lambda.hpp>