diff --git a/protos/core_adapter.proto b/protos/core_adapter.proto
index 5021b9a..d828194 100644
--- a/protos/core_adapter.proto
+++ b/protos/core_adapter.proto
@@ -1,6 +1,9 @@
 syntax = "proto3";
 
 import "google/protobuf/any.proto";
+import "openflow_13.proto";
+import public "logical_device.proto";
+
 
 option go_package = "github.com/opencord/voltha-go/protos/core_adapter";
 
@@ -18,8 +21,14 @@
     bool val = 1;
 }
 
+enum ErrorCode {
+        UNSUPPORTED_REQUEST = 0;
+        INVALID_PARAMETERS = 1;
+}
+
 message Error {
-    string reason = 1;
+    ErrorCode code = 1;
+    string reason = 2;
 }
 
 enum MessageType {
@@ -56,3 +65,12 @@
     bool success = 1;
     google.protobuf.Any result = 3;
 }
+
+message SwitchCapability {
+    openflow_13.ofp_desc desc = 1;
+    openflow_13.ofp_switch_features switch_features = 2;
+}
+
+message PortCapability {
+    LogicalPort port = 1;
+}
\ No newline at end of file