diff --git a/core/api/src/main/java/org/onlab/onos/net/flow/DefaultTrafficSelector.java b/core/api/src/main/java/org/onlab/onos/net/flow/DefaultTrafficSelector.java
index b840318..fa8a64c 100644
--- a/core/api/src/main/java/org/onlab/onos/net/flow/DefaultTrafficSelector.java
+++ b/core/api/src/main/java/org/onlab/onos/net/flow/DefaultTrafficSelector.java
@@ -55,6 +55,16 @@
     }
 
     @Override
+    public Criterion getCriterion(Criterion.Type type) {
+        for (Criterion c : criteria) {
+            if (c.type() == type) {
+                return c;
+            }
+        }
+        return null;
+    }
+
+    @Override
     public int hashCode() {
         return Objects.hash(criteria);
     }
diff --git a/core/api/src/main/java/org/onlab/onos/net/flow/TrafficSelector.java b/core/api/src/main/java/org/onlab/onos/net/flow/TrafficSelector.java
index ab9b4a1..bcaf70c 100644
--- a/core/api/src/main/java/org/onlab/onos/net/flow/TrafficSelector.java
+++ b/core/api/src/main/java/org/onlab/onos/net/flow/TrafficSelector.java
@@ -39,6 +39,15 @@
     Set<Criterion> criteria();
 
     /**
+     * Returns the selection criterion for a particular type, if it exists in
+     * this traffic selector.
+     *
+     * @param type criterion type to look up
+     * @return the criterion of the specified type if one exists, otherwise null
+     */
+    Criterion getCriterion(Criterion.Type type);
+
+    /**
      * Builder of traffic selector entities.
      */
     public interface Builder {