diff --git a/openair3/NAS/NR_UE/nr_nas_msg.h b/openair3/NAS/NR_UE/nr_nas_msg.h
index 380da8cbbc..ae42174fda 100644
--- a/openair3/NAS/NR_UE/nr_nas_msg.h
+++ b/openair3/NAS/NR_UE/nr_nas_msg.h
@@ -59,6 +59,16 @@ typedef enum fgs_mm_state_e {
   FGS_SERVICE_REQUEST_INITIATED,
 } fgs_mm_state_t;
 
+/*
+ * 5GS mobility management (5GMM) modes
+ * 5.1.3.2.1.1 of TS 24.501
+ */
+typedef enum fgs_mm_mode_e {
+  FGS_NOT_CONNECTED,
+  FGS_IDLE,
+  FGS_CONNECTED,
+} fgs_mm_mode_t;
+
 /* Security Key for SA UE */
 typedef struct {
   uint8_t kausf[32];
@@ -76,6 +86,8 @@ typedef struct {
 typedef struct {
   /* 5GS Mobility Management States (5.1.3.2.1 of 3GPP TS 24.501) */
   fgs_mm_state_t fiveGMM_state;
+  /* 5GS Mobility Management mode */
+  fgs_mm_mode_t fiveGMM_mode;
   uicc_t *uicc;
   ue_sa_security_key_t security;
   stream_security_container_t *security_container;