diff --git a/library/L3_Common.ttcn b/library/L3_Common.ttcn
index bf7818a..57db6b3 100644
--- a/library/L3_Common.ttcn
+++ b/library/L3_Common.ttcn
@@ -11,7 +11,11 @@
 	OCT16 ik,
 	OCT16 ck,
 	OCT16 autn,
-	OCT8 res
+	OCT8 res,
+	/* auts is usally calculated from autn + rand on the MS.
+	 * To simplify the test case, auts is generated instead calculated here.
+	 */
+	OCT14 auts
 }
 
 private function f_rnd_oct(integer len) return octetstring {
@@ -37,6 +41,7 @@
 	vec.ck := f_rnd_oct(16);
 	vec.autn := f_rnd_oct(16);
 	vec.res := f_rnd_oct(8);
+	vec.auts := f_rnd_oct(14);
 	return vec;
 }