diff --git a/src/main/java/net/floodlightcontroller/linkdiscovery/internal/LinkDiscoveryManager.java b/src/main/java/net/floodlightcontroller/linkdiscovery/internal/LinkDiscoveryManager.java
index c940cf024967fc12199669006c3c157fa14c3092..cf3343c2c27aafbac1ef343f416b7f39d3ae51e5 100644
--- a/src/main/java/net/floodlightcontroller/linkdiscovery/internal/LinkDiscoveryManager.java
+++ b/src/main/java/net/floodlightcontroller/linkdiscovery/internal/LinkDiscoveryManager.java
@@ -786,11 +786,11 @@ 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);