diff --git a/src/main/java/net/floodlightcontroller/linkdiscovery/internal/LinkDiscoveryManager.java b/src/main/java/net/floodlightcontroller/linkdiscovery/internal/LinkDiscoveryManager.java
index f5f786cb6d37425af1114ffcddae85b96edef0c8..dd2f6f8b0e87a6196c1c41fe9e87dcc413740bd4 100644
--- a/src/main/java/net/floodlightcontroller/linkdiscovery/internal/LinkDiscoveryManager.java
+++ b/src/main/java/net/floodlightcontroller/linkdiscovery/internal/LinkDiscoveryManager.java
@@ -788,11 +788,11 @@ IFloodlightModule, IInfoProvider, IHAListener {
                 switchLinks.get(lt.getDst()).add(lt);
 
                 // index both ends by switch:port
-                if (!portLinks.containsKey(lt.getSrc()))
+                if (!portLinks.containsKey(srcNpt))
                     portLinks.put(srcNpt, new HashSet<Link>());
                 portLinks.get(srcNpt).add(lt);
 
-                if (!portLinks.containsKey(lt.getDst()))
+                if (!portLinks.containsKey(dstNpt))
                     portLinks.put(dstNpt, new HashSet<Link>());
                 portLinks.get(dstNpt).add(lt);