diff --git a/examples/isl-example.cc b/examples/isl-example.cc
index 74501c6..93a75e4 100644
--- a/examples/isl-example.cc
+++ b/examples/isl-example.cc
@@ -43,7 +43,7 @@ main (int argc, char *argv[])
   Ipv6InterfaceContainer interfaces = address.Assign (devices);
 
   NdCacheHelper nsHelper;
-  nsHelper.Install (nodes, interfaces);
+  nsHelper.Install (devices, interfaces);
 
   UdpEchoServerHelper echoServer (9);
   ApplicationContainer serverApps = echoServer.Install (nodes);
diff --git a/helper/nd-cache-helper.cc b/helper/nd-cache-helper.cc
index 36c98a4..bcf94e1 100644
--- a/helper/nd-cache-helper.cc
+++ b/helper/nd-cache-helper.cc
@@ -16,8 +16,8 @@ NdCacheHelper::Install (NetDeviceContainer &devices, Ipv6InterfaceContainer &int
     {
       Ptr<NetDevice> dev = devices.Get (i);
       Ptr<Node> node = dev->GetNode ();
-      uint32_t ifIndex = dev->GetIfIndex ();
       Ptr<Ipv6L3Protocol> ipv6 = node->GetObject<Ipv6L3Protocol> ();
+      int32_t ifIndex = ipv6->GetInterfaceForDevice (dev);
       Ptr<Ipv6Interface> interface = ipv6->GetInterface (ifIndex);
       Ptr<NdiscCache> cache = interface->GetNdiscCache ();
       for (uint32_t j = 0; j < devices.GetN (); j++)