diff --git a/openbsc/src/libmsc/smpp_openbsc.c b/openbsc/src/libmsc/smpp_openbsc.c
index 8e0085d..eb1ac11 100644
--- a/openbsc/src/libmsc/smpp_openbsc.c
+++ b/openbsc/src/libmsc/smpp_openbsc.c
@@ -259,6 +259,10 @@
 		return 0;
 
 	switch (signal) {
+	case S_SMS_MEM_EXCEEDED:
+		/* fall-through: There is no ESME_Rxxx result code to
+		 * indicate a MEMORY EXCEEDED in transaction mode back
+		 * to the ESME */
 	case S_SMS_UNKNOWN_ERROR:
 		if (sms->smpp.transaction_mode) {
 			/* Send back the SUBMIT-SM response with apropriate error */