diff --git a/openair1/SIMULATION/NR_PHY/dlsim.c b/openair1/SIMULATION/NR_PHY/dlsim.c
index 848ae2920e..c924e28dc8 100644
--- a/openair1/SIMULATION/NR_PHY/dlsim.c
+++ b/openair1/SIMULATION/NR_PHY/dlsim.c
@@ -129,6 +129,12 @@ rrc_data_ind(
 {
 }
 
+int ocp_gtpv1u_create_s1u_tunnel(instance_t instance,
+                                 const gtpv1u_enb_create_tunnel_req_t  *create_tunnel_req,
+                                 gtpv1u_enb_create_tunnel_resp_t *create_tunnel_resp) {
+    return 0;
+}
+
 int
 gtpv1u_create_s1u_tunnel(
   const instance_t                              instanceP,
diff --git a/openair1/SIMULATION/NR_PHY/prachsim.c b/openair1/SIMULATION/NR_PHY/prachsim.c
index 9cd72d1a9c..6ca7a9dde0 100644
--- a/openair1/SIMULATION/NR_PHY/prachsim.c
+++ b/openair1/SIMULATION/NR_PHY/prachsim.c
@@ -92,6 +92,12 @@ rrc_data_ind(
 {
 }
 
+int ocp_gtpv1u_create_s1u_tunnel(instance_t instance,
+                                 const gtpv1u_enb_create_tunnel_req_t  *create_tunnel_req,
+                                 gtpv1u_enb_create_tunnel_resp_t *create_tunnel_resp) {
+    return 0;
+}
+
 int
 gtpv1u_create_s1u_tunnel(
   const instance_t                              instanceP,
diff --git a/openair1/SIMULATION/NR_PHY/ulsim.c b/openair1/SIMULATION/NR_PHY/ulsim.c
index 4dc9622664..a99a47dc54 100644
--- a/openair1/SIMULATION/NR_PHY/ulsim.c
+++ b/openair1/SIMULATION/NR_PHY/ulsim.c
@@ -121,6 +121,12 @@ rrc_data_ind(
 {
 }
 
+int ocp_gtpv1u_create_s1u_tunnel(instance_t instance,
+                                 const gtpv1u_enb_create_tunnel_req_t  *create_tunnel_req,
+                                 gtpv1u_enb_create_tunnel_resp_t *create_tunnel_resp) {
+    return 0;
+}
+
 int
 gtpv1u_create_s1u_tunnel(
   const instance_t                              instanceP,