diff --git a/core/common/src/main/java/org/onosproject/codec/impl/EncodeCriterionCodecHelper.java b/core/common/src/main/java/org/onosproject/codec/impl/EncodeCriterionCodecHelper.java
index 33dd46a..1852ee2 100644
--- a/core/common/src/main/java/org/onosproject/codec/impl/EncodeCriterionCodecHelper.java
+++ b/core/common/src/main/java/org/onosproject/codec/impl/EncodeCriterionCodecHelper.java
@@ -127,6 +127,7 @@
         formatMap.put(Criterion.Type.TCP_FLAGS, new FormatUnknown());
         formatMap.put(Criterion.Type.ACTSET_OUTPUT, new FormatUnknown());
         formatMap.put(Criterion.Type.PACKET_TYPE, new FormatUnknown());
+        formatMap.put(Criterion.Type.EXTENSION, new FormatUnknown());
     }
 
     private interface CriterionTypeFormatter {