diff --git a/include/osmocom/gsm/protocol/gsm_29_118.h b/include/osmocom/gsm/protocol/gsm_29_118.h
index 97a9c43..70f1500 100644
--- a/include/osmocom/gsm/protocol/gsm_29_118.h
+++ b/include/osmocom/gsm/protocol/gsm_29_118.h
@@ -170,4 +170,7 @@
 #define SGS_NS10_DEFAULT	2
 #define SGS_NS12_DEFAULT	2
 
+/* TS 29.118 Section 6.3 */
+#define SGS_PORT_DEFAULT 29118
+
 const struct tlv_definition sgsap_ie_tlvdef;