diff --git a/src/main/java/net/floodlightcontroller/core/internal/Controller.java b/src/main/java/net/floodlightcontroller/core/internal/Controller.java
index 6f2d166..0cbcfcb 100644
--- a/src/main/java/net/floodlightcontroller/core/internal/Controller.java
+++ b/src/main/java/net/floodlightcontroller/core/internal/Controller.java
@@ -107,6 +107,7 @@
 import org.openflow.protocol.OFPacketIn;
 import org.openflow.protocol.OFPhysicalPort;
 import org.openflow.protocol.OFPortStatus;
+import org.openflow.protocol.OFPhysicalPort.OFPortState;
 import org.openflow.protocol.OFPortStatus.OFPortReason;
 import org.openflow.protocol.OFSetConfig;
 import org.openflow.protocol.OFStatisticsRequest;
@@ -1144,8 +1145,16 @@
         short portNumber = m.getDesc().getPortNumber();
         OFPhysicalPort port = m.getDesc();
         if (m.getReason() == (byte)OFPortReason.OFPPR_MODIFY.ordinal()) {
+        	int srcPortState = port.getState();
+            boolean portUp = ((srcPortState &
+                    OFPortState.OFPPS_STP_MASK.getValue()) !=
+                    OFPortState.OFPPS_STP_BLOCK.getValue());
             sw.setPort(port);
-            swStore.addPort(sw.getStringId(), port);
+           if (portUp) {
+               swStore.addPort(sw.getStringId(), port);
+           } else {
+        	   swStore.deletePort(sw.getStringId(), port.getPortNumber());
+           }
             if (updateStorage)
                 updatePortInfo(sw, port);
             log.debug("Port #{} modified for {}", portNumber, sw);
diff --git a/src/main/java/net/floodlightcontroller/linkdiscovery/internal/LinkStorageImpl.java b/src/main/java/net/floodlightcontroller/linkdiscovery/internal/LinkStorageImpl.java
index 31814af..dd743ba 100644
--- a/src/main/java/net/floodlightcontroller/linkdiscovery/internal/LinkStorageImpl.java
+++ b/src/main/java/net/floodlightcontroller/linkdiscovery/internal/LinkStorageImpl.java
@@ -1,5 +1,6 @@
 package net.floodlightcontroller.linkdiscovery.internal;
 
+import java.util.ArrayList;
 import java.util.List;
 import java.util.Set;
 
@@ -98,9 +99,16 @@
             
             if (vportSrc != null && vportDst != null) {
             	//TODO: If Edge already exists should we remove and add again?
-            	if (vportSrc.query().direction(Direction.OUT).labels("link").vertices().iterator().hasNext() &&
-            		vportSrc.query().direction(Direction.OUT).labels("link").vertices().iterator().next().equals(vportDst)) {
+            	List<Vertex> currLinks = new ArrayList<Vertex>();
+            	for (Vertex V : vportSrc.query().direction(Direction.OUT).labels("link").vertices()) {
+            		currLinks.add(V);
+            	}
+            	
+            	if (currLinks.contains(vportDst)) {
+            	// if (vportSrc.query().direction(Direction.OUT).labels("link").vertices().iterator().hasNext() &&
+            	//	vportSrc.query().direction(Direction.OUT).labels("link").) {
             		//FIXME: Succeed silently for now
+            		log.debug("addLink(): Failure: link exists {} src {} dst {}", new Object[]{lt, vportSrc, vportDst});
             	} else {
             		graph.addEdge(null, vportSrc, vportDst, "link");
             		graph.stopTransaction(Conclusion.SUCCESS);