diff --git a/src/internet/model/arp-cache.cc b/src/internet/model/arp-cache.cc
index 0c4a06f9b..43d05fdb8 100644
--- a/src/internet/model/arp-cache.cc
+++ b/src/internet/model/arp-cache.cc
@@ -421,6 +421,8 @@ ArpCache::Entry::MarkWaitReply (Ptr<Packet> waiting)
   NS_LOG_FUNCTION (this << waiting);
   NS_ASSERT (m_state == ALIVE || m_state == DEAD);
   NS_ASSERT (m_pending.empty ());
+  NS_ASSERT_MSG (waiting, "Can not add a null packet to the ARP queue");
+
   m_state = WAIT_REPLY;
   m_pending.push_back (waiting);
   UpdateSeen ();
diff --git a/src/lte/test/epc-test-s1u-uplink.cc b/src/lte/test/epc-test-s1u-uplink.cc
index 8499eb357..986416e89 100644
--- a/src/lte/test/epc-test-s1u-uplink.cc
+++ b/src/lte/test/epc-test-s1u-uplink.cc
@@ -399,8 +399,8 @@ EpcS1uUlTestCase::DoRun ()
           Ptr<ArpCache> ueArpCache = ueLteIpv4Iface->GetArpCache (); 
           ueArpCache->SetAliveTimeout (Seconds (1000));          
           ArpCache::Entry* arpCacheEntry = ueArpCache->Add (gwAddr);
-          arpCacheEntry->MarkWaitReply(0);
-          arpCacheEntry->MarkAlive (Mac48Address::GetBroadcast ()); 
+          arpCacheEntry->SetMacAddresss (Mac48Address::GetBroadcast ());
+          arpCacheEntry->MarkPermanent ();
   
           
           PacketSinkHelper packetSinkHelper ("ns3::UdpSocketFactory",