diff --git a/src/main/java/net/onrc/onos/core/topology/PortImpl.java b/src/main/java/net/onrc/onos/core/topology/PortImpl.java
index e88d23b..5d46005 100644
--- a/src/main/java/net/onrc/onos/core/topology/PortImpl.java
+++ b/src/main/java/net/onrc/onos/core/topology/PortImpl.java
@@ -2,8 +2,10 @@
 
 import java.util.Collections;
 import java.util.HashSet;
+import java.util.Map;
 import java.util.Set;
 
+import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
 import net.onrc.onos.core.util.SwitchPort;
 
 /**
@@ -107,6 +109,28 @@
     }
 
     @Override
+    public String getStringAttribute(String attr) {
+        throw new UnsupportedOperationException("Not implemented yet");
+    }
+
+    @Override
+    @SuppressFBWarnings(value = "RCN_REDUNDANT_NULLCHECK_OF_NONNULL_VALUE",
+       justification = "getStringAttribute might return null once implemented")
+    public String getStringAttribute(String attr, String def) {
+        final String v = getStringAttribute(attr);
+        if (v == null) {
+            return def;
+        } else {
+            return v;
+        }
+    }
+
+    @Override
+    public Map<String, String> getAllStringAttributes() {
+        throw new UnsupportedOperationException("Not implemented yet");
+    }
+
+    @Override
     public String toString() {
         return String.format("%d:%d",
                 getSwitch().getDpid(),