diff --git a/lib/diameter/gy/message.c b/lib/diameter/gy/message.c
index 23ac5b4a2..c50b277e2 100644
--- a/lib/diameter/gy/message.c
+++ b/lib/diameter/gy/message.c
@@ -54,6 +54,7 @@ struct dict_object *ogs_diam_gy_pdp_address = NULL;
 struct dict_object *ogs_diam_gy_sgsn_address = NULL;
 struct dict_object *ogs_diam_gy_ggsn_address = NULL;
 struct dict_object *ogs_diam_gy_3gpp_nsapi = NULL;
+struct dict_object *ogs_diam_gy_3gpp_selection_mode = NULL;
 
 struct dict_object *ogs_diam_gy_feature_list_id = NULL;
 struct dict_object *ogs_diam_gy_feature_list = NULL;
@@ -115,6 +116,7 @@ int ogs_diam_gy_init(void)
 	CHECK_dict_search(DICT_AVP, AVP_BY_NAME_ALL_VENDORS, "SGSN-Address", &ogs_diam_gy_sgsn_address);
 	CHECK_dict_search(DICT_AVP, AVP_BY_NAME_ALL_VENDORS, "GGSN-Address", &ogs_diam_gy_ggsn_address);
 	CHECK_dict_search(DICT_AVP, AVP_BY_NAME_ALL_VENDORS, "3GPP-NSAPI", &ogs_diam_gy_3gpp_nsapi);
+	CHECK_dict_search(DICT_AVP, AVP_BY_NAME_ALL_VENDORS, "3GPP-Selection-Mode", &ogs_diam_gy_3gpp_selection_mode);
 
 
 	CHECK_dict_search(DICT_AVP, AVP_BY_NAME_ALL_VENDORS, "Feature-List-ID", &ogs_diam_gy_feature_list_id);
diff --git a/lib/diameter/gy/message.h b/lib/diameter/gy/message.h
index 0f3210d56..1db2ac99f 100644
--- a/lib/diameter/gy/message.h
+++ b/lib/diameter/gy/message.h
@@ -105,6 +105,7 @@ extern struct dict_object *ogs_diam_gy_pdp_address;
 extern struct dict_object *ogs_diam_gy_sgsn_address;
 extern struct dict_object *ogs_diam_gy_ggsn_address;
 extern struct dict_object *ogs_diam_gy_3gpp_nsapi;
+extern struct dict_object *ogs_diam_gy_3gpp_selection_mode;
 extern struct dict_object *ogs_diam_gy_feature_list_id;
 extern struct dict_object *ogs_diam_gy_feature_list;
 extern struct dict_object *ogs_diam_gy_qos_information;
diff --git a/lib/gtp/v1/message.c b/lib/gtp/v1/message.c
index 01f123627..524fc3280 100644
--- a/lib/gtp/v1/message.c
+++ b/lib/gtp/v1/message.c
@@ -21,7 +21,7 @@
 /*******************************************************************************
  * This file had been created by gtp1-tlv.py script v0.1.0
  * Please do not modify this file but regenerate it via script.
- * Created on: 2022-02-18 19:21:27.743742 by pespin
+ * Created on: 2022-05-12 14:42:38.611950 by pespin
  * from 29060-g00.docx
  ******************************************************************************/
 
@@ -150,7 +150,7 @@ ogs_tlv_desc_t ogs_gtp1_tlv_desc_recovery =
 
 ogs_tlv_desc_t ogs_gtp1_tlv_desc_selection_mode =
 {
-    OGS_TV_FIXED_STR,
+    OGS_TV_UINT8,
     "Selection Mode",
     OGS_GTP1_SELECTION_MODE_TYPE,
     1,
diff --git a/lib/gtp/v1/message.h b/lib/gtp/v1/message.h
index 011bc4cc2..98155e46e 100644
--- a/lib/gtp/v1/message.h
+++ b/lib/gtp/v1/message.h
@@ -21,7 +21,7 @@
 /*******************************************************************************
  * This file had been created by gtp1-tlv.py script v0.1.0
  * Please do not modify this file but regenerate it via script.
- * Created on: 2022-02-18 19:21:27.730656 by pespin
+ * Created on: 2022-05-12 14:42:38.599141 by pespin
  * from 29060-g00.docx
  ******************************************************************************/
 
@@ -471,7 +471,7 @@ typedef ogs_tlv_octet_t ogs_gtp1_tlv_map_cause_t;
 typedef ogs_tlv_octet_t ogs_gtp1_tlv_p_tmsi_signature_t;
 typedef ogs_tlv_octet_t ogs_gtp1_tlv_ms_validated_t;
 typedef ogs_tlv_uint8_t ogs_gtp1_tlv_recovery_t;
-typedef ogs_tlv_octet_t ogs_gtp1_tlv_selection_mode_t;
+typedef ogs_tlv_uint8_t ogs_gtp1_tlv_selection_mode_t;
 typedef ogs_tlv_uint32_t ogs_gtp1_tlv_tunnel_endpoint_identifier_data_i_t;
 typedef ogs_tlv_uint32_t ogs_gtp1_tlv_tunnel_endpoint_identifier_control_plane_t;
 typedef ogs_tlv_octet_t ogs_gtp1_tlv_tunnel_endpoint_identifier_data_ii_t;
diff --git a/lib/gtp/v1/support/gtp1-tlv.py b/lib/gtp/v1/support/gtp1-tlv.py
index 655592ca7..c68481099 100644
--- a/lib/gtp/v1/support/gtp1-tlv.py
+++ b/lib/gtp/v1/support/gtp1-tlv.py
@@ -315,6 +315,7 @@ set_c_type("Trace Type", 'uint')
 set_c_type("MS Not Reachable Reason", 'uint')
 set_c_type("Charging ID", 'uint')
 set_c_type("Reordering Required", 'uint')
+set_c_type("Selection Mode", 'uint')
 
 msg_list["Echo Request"]["table"] = 12
 msg_list["Echo Response"]["table"] = 13
diff --git a/src/smf/context.h b/src/smf/context.h
index e4561f0e3..f2980be91 100644
--- a/src/smf/context.h
+++ b/src/smf/context.h
@@ -318,6 +318,7 @@ typedef struct smf_sess_s {
         ogs_tlv_octet_t ue_timezone;
         bool create_session_response_apn_ambr;
         bool create_session_response_bearer_qos;
+        uint8_t selection_mode; /* OGS_GTP{1,2}_SELECTION_MODE_*, same in GTPv1C and 2C. */
         struct {
             uint8_t nsapi;
         } v1;  /* GTPv1C specific fields */
diff --git a/src/smf/gn-handler.c b/src/smf/gn-handler.c
index 665e00140..27556e98f 100644
--- a/src/smf/gn-handler.c
+++ b/src/smf/gn-handler.c
@@ -77,6 +77,10 @@ uint8_t smf_gn_handle_create_pdp_context_request(
         ogs_error("No IMSI");
         cause_value = OGS_GTP1_CAUSE_MANDATORY_IE_MISSING;
     }
+    if (req->selection_mode.presence == 0) {
+        ogs_error("No Selection Mode");
+        cause_value = OGS_GTP1_CAUSE_MANDATORY_IE_MISSING;
+    }
     if (req->tunnel_endpoint_identifier_data_i.presence == 0) {
         ogs_error("No TEID");
         cause_value = OGS_GTP1_CAUSE_MANDATORY_IE_MISSING;
@@ -119,6 +123,10 @@ uint8_t smf_gn_handle_create_pdp_context_request(
 
     /* Store NSAPI */
     sess->gtp.v1.nsapi = req->nsapi.u8;
+    /* Selection Mode, TS 29.060 7.7.12 */
+    sess->gtp.selection_mode = req->selection_mode.u8 & 0x03;
+    if (sess->gtp.selection_mode > 2)
+        sess->gtp.selection_mode = 2;
 
     /* Control Plane(DL) : SGW-S5C */
     sess->sgw_s5c_teid = req->tunnel_endpoint_identifier_control_plane.u32;
diff --git a/src/smf/gy-path.c b/src/smf/gy-path.c
index 577cd7b15..900673b2d 100644
--- a/src/smf/gy-path.c
+++ b/src/smf/gy-path.c
@@ -255,6 +255,7 @@ static void fill_service_information_ccr(smf_sess_t *sess,
     struct sockaddr_in sin;
     struct sockaddr_in6 sin6;
     char buf[OGS_PLMNIDSTRLEN];
+    char digit;
 
     /* Service-Information, TS 32.299 sec 7.2.192 */
     ret = fd_msg_avp_new(ogs_diam_gy_service_information, 0, &avp);
@@ -373,6 +374,18 @@ static void fill_service_information_ccr(smf_sess_t *sess,
     ret = fd_msg_avp_add(avpch1, MSG_BRW_LAST_CHILD, avpch2);
     ogs_assert(ret == 0);
 
+    /* 3GPP-Selection-Mode, 3GPP TS 29.061 16.4.7.2 12 */
+    ret = fd_msg_avp_new(ogs_diam_gy_3gpp_selection_mode, 0, &avpch2);
+    ogs_assert(ret == 0);
+    ogs_assert(sess->session.name);
+    digit = sess->gtp.selection_mode + '0';
+    val.os.data = (uint8_t*)&digit;
+    val.os.len = 1;
+    ret = fd_msg_avp_setvalue(avpch2, &val);
+    ogs_assert(ret == 0);
+    ret = fd_msg_avp_add(avpch1, MSG_BRW_LAST_CHILD, avpch2);
+    ogs_assert(ret == 0);
+
     /* 3GPP-SGSN-MCC-MNC */
     ret = fd_msg_avp_new(ogs_diam_gy_3gpp_sgsn_mcc_mnc, 0, &avpch2);
     ogs_assert(ret == 0);
diff --git a/src/smf/s5c-handler.c b/src/smf/s5c-handler.c
index 8ce542958..f70fe1549 100644
--- a/src/smf/s5c-handler.c
+++ b/src/smf/s5c-handler.c
@@ -166,6 +166,13 @@ uint8_t smf_s5c_handle_create_session_request(
         }
     }
 
+    /* Set Selection Mode, TS 29.274 8.58 */
+    if (req->selection_mode.presence == 1) {
+        sess->gtp.selection_mode = req->selection_mode.u8 & 0x03;
+        if (sess->gtp.selection_mode > 2)
+            sess->gtp.selection_mode = 2;
+    }
+
     if (sess->gtp_rat_type == OGS_GTP2_RAT_TYPE_EUTRAN) {
         /* User Location Inforation is mandatory only for E-UTRAN */
         ogs_assert(req->user_location_information.presence);