diff --git a/include/osmocom/msc/gsm_data.h b/include/osmocom/msc/gsm_data.h
index a90b732..11b6e82 100644
--- a/include/osmocom/msc/gsm_data.h
+++ b/include/osmocom/msc/gsm_data.h
@@ -258,6 +258,9 @@
 
 	/* Whether we want to use Osmux against BSCs. Controlled via VTY */
 	enum osmux_usage use_osmux;
+
+	/* Whether to use call waiting on the network */
+	bool call_waiting;
 };
 
 struct osmo_esme;
diff --git a/src/libmsc/gsm_04_08_cc.c b/src/libmsc/gsm_04_08_cc.c
index e83caa2..ed74e88 100644
--- a/src/libmsc/gsm_04_08_cc.c
+++ b/src/libmsc/gsm_04_08_cc.c
@@ -1909,6 +1909,25 @@
 						GSM48_CAUSE_LOC_PRN_S_LU,
 						GSM48_CC_CAUSE_DEST_OOO);
 		}
+
+		/* Find valid conn */
+		msc_a = msc_a_for_vsub(vsub, true);
+
+		/* If subscriber is BUSY and we do not DO call in call aka "call-waiting" */
+		if (!net->call_waiting && msc_a) {
+			struct gsm_trans *existing_cc_trans = trans_find_by_type(msc_a, TRANS_CC);
+			if (existing_cc_trans && existing_cc_trans->cc.state != GSM_CSTATE_NULL) {
+				LOG_TRANS_CAT(existing_cc_trans, DCC, LOGL_NOTICE,
+					      "rx '%s' for subscriber %s with trans state (%s)"
+					      " rejecting with USER_BUSY\n",
+					get_mncc_name(msg->msg_type), data->called.number,
+					gsm48_cc_state_name(existing_cc_trans->cc.state));
+				return mncc_release_ind(net, NULL, data->callref,
+							GSM48_CAUSE_LOC_PRN_S_LU,
+							GSM48_CC_CAUSE_USER_BUSY);
+			}
+		}
+
 		/* Create transaction */
 		trans = trans_alloc(net, vsub, TRANS_CC,
 				    TRANS_ID_UNASSIGNED, data->callref);
@@ -1922,9 +1941,6 @@
 			return -ENOMEM;
 		}
 
-		/* Find valid conn */
-		msc_a = msc_a_for_vsub(vsub, true);
-
 		/* If subscriber has no conn */
 		if (!msc_a) {
 
diff --git a/src/libmsc/msc_vty.c b/src/libmsc/msc_vty.c
index 4674e2e..09aef91 100644
--- a/src/libmsc/msc_vty.c
+++ b/src/libmsc/msc_vty.c
@@ -330,6 +330,29 @@
 	return CMD_SUCCESS;
 }
 
+DEFUN(cfg_net_call_wait, cfg_net_call_wait_cmd,
+      "call-waiting",
+      "Enable Call Waiting on the Network\n")
+{
+	struct gsm_network *net = vty->index;
+
+	net->call_waiting = true;
+
+	return CMD_SUCCESS;
+}
+
+DEFUN(cfg_net_no_call_wait, cfg_net_no_call_wait_cmd,
+      "no call-waiting",
+      NO_STR
+      "Disable Call Waiting on the Network\n")
+{
+	struct gsm_network *net = vty->index;
+
+	net->call_waiting = false;
+
+	return CMD_SUCCESS;
+}
+
 static int config_write_net(struct vty *vty)
 {
 	int i;
@@ -376,6 +399,9 @@
 			gsmnet->emergency.route_to_msisdn, VTY_NEWLINE);
 	}
 
+	if (!gsmnet->call_waiting)
+		vty_out(vty, " no call-waiting%s", VTY_NEWLINE);
+
 	return CMD_SUCCESS;
 }
 
@@ -1946,6 +1972,8 @@
 	install_element(GSMNET_NODE, &cfg_net_no_timezone_cmd);
 	install_element(GSMNET_NODE, &cfg_net_per_loc_upd_cmd);
 	install_element(GSMNET_NODE, &cfg_net_no_per_loc_upd_cmd);
+	install_element(GSMNET_NODE, &cfg_net_call_wait_cmd);
+	install_element(GSMNET_NODE, &cfg_net_no_call_wait_cmd);
 
 	install_element(CONFIG_NODE, &cfg_msc_cmd);
 	install_node(&msc_node, config_write_msc);
diff --git a/src/osmo-msc/msc_main.c b/src/osmo-msc/msc_main.c
index 1083271..3860589 100644
--- a/src/osmo-msc/msc_main.c
+++ b/src/osmo-msc/msc_main.c
@@ -216,6 +216,7 @@
 
 	mgcp_client_conf_init(&net->mgw.conf);
 	net->mgw.tdefs = g_mgw_tdefs;
+	net->call_waiting = true;
 
 	return net;
 }
diff --git a/tests/test_nodes.vty b/tests/test_nodes.vty
index 0ad390f..a4e0e15 100644
--- a/tests/test_nodes.vty
+++ b/tests/test_nodes.vty
@@ -26,6 +26,8 @@
   no timezone
   periodic location update <6-1530>
   no periodic location update
+  call-waiting
+  no call-waiting
 
 OsmoMSC(config-net)# encryption?
   encryption  Encryption options