diff --git a/c_gen/c_test_gen.py b/c_gen/c_test_gen.py
index 71615e6..9b70e52 100644
--- a/c_gen/c_test_gen.py
+++ b/c_gen/c_test_gen.py
@@ -105,6 +105,8 @@
         of_bsn_vport_q_in_q_t="vport",
         of_bitmap_128_t="bitmap_128",
         of_checksum_128_t="checksum_128",
+	#Circuit extensions
+        oxm_of_och_sig_id_t="sig_id",		
         )
 
     if m_type.find("of_list_") == 0: