diff --git a/include/osmocom/mgcp/mgcp_common.h b/include/osmocom/mgcp/mgcp_common.h
index 0eb1388..29dc458 100644
--- a/include/osmocom/mgcp/mgcp_common.h
+++ b/include/osmocom/mgcp/mgcp_common.h
@@ -68,4 +68,8 @@
 	return 0;
 }
 
+/* String length of Connection Identifiers
+ * (see also RFC3435 2.1.3.2 Names of Connections) */
+#define MGCP_CONN_ID_LENGTH 32+1
+
 #endif