--- a/src/lte/model/lte-pdcp-header.cc	Fri Jan 18 12:10:00 2013 +0100
+++ b/src/lte/model/lte-pdcp-header.cc	Fri Jan 18 12:31:51 2013 +0100
@@ -109,6 +109,8 @@
   byte_1 = i.ReadU8 ();
   byte_2 = i.ReadU8 ();
   m_dcBit = (byte_1 & 0x80) > 7;
+  // For now, we just support DATA PDUs
+  NS_ASSERT (m_dcBit == DATA_PDU);
   m_sequenceNumber = ((byte_1 & 0x0F) << 8) | byte_2;
 
   return GetSerializedSize ();