diff --git a/lib/librte_ether/rte_ethdev.c b/lib/librte_ether/rte_ethdev.c
index 95f2ceb..9f713ae 100644
--- a/lib/librte_ether/rte_ethdev.c
+++ b/lib/librte_ether/rte_ethdev.c
@@ -175,6 +175,16 @@ enum {
 	STAT_QMAP_RX
 };
 
+enum {
+	DEV_VALID = 0,
+	DEV_INVALID
+};
+
+enum {
+	DEV_DISCONNECTED = 0,
+	DEV_CONNECTED
+};
+
 static inline void
 rte_eth_dev_data_alloc(void)
 {
@@ -201,19 +211,34 @@ rte_eth_dev_allocated(const char *name)
 {
 	unsigned i;
 
-	for (i = 0; i < nb_ports; i++) {
-		if (strcmp(rte_eth_devices[i].data->name, name) == 0)
+	for (i = 0; i < RTE_MAX_ETHPORTS; i++) {
+		if ((rte_eth_devices[i].attached == DEV_CONNECTED)
+				&& strcmp(rte_eth_devices[i].data->name,
+					name) == 0)
 			return &rte_eth_devices[i];
 	}
 	return NULL;
 }
 
+static uint8_t
+rte_eth_dev_allocate_new_port(void)
+{
+	unsigned i;
+
+	for (i = 0; i < RTE_MAX_ETHPORTS; i++)
+		if (rte_eth_devices[i].attached == DEV_DISCONNECTED)
+			return i;
+	return RTE_MAX_ETHPORTS;
+}
+
 struct rte_eth_dev *
 rte_eth_dev_allocate(const char *name)
 {
+	uint8_t port_id;
 	struct rte_eth_dev *eth_dev;
 
-	if (nb_ports == RTE_MAX_ETHPORTS) {
+	port_id = rte_eth_dev_allocate_new_port();
+	if (port_id == RTE_MAX_ETHPORTS) {
 		PMD_DEBUG_TRACE("Reached maximum number of Ethernet ports\n");
 		return NULL;
 	}
@@ -226,10 +251,12 @@ rte_eth_dev_allocate(const char *name)
 		return NULL;
 	}
 
-	eth_dev = &rte_eth_devices[nb_ports];
-	eth_dev->data = &rte_eth_dev_data[nb_ports];
+	eth_dev = &rte_eth_devices[port_id];
+	eth_dev->data = &rte_eth_dev_data[port_id];
 	snprintf(eth_dev->data->name, sizeof(eth_dev->data->name), "%s", name);
-	eth_dev->data->port_id = nb_ports++;
+	eth_dev->data->port_id = port_id;
+	eth_dev->attached = DEV_CONNECTED;
+	nb_ports++;
 	return eth_dev;
 }
 
@@ -283,6 +310,7 @@ rte_eth_dev_init(struct rte_pci_driver *pci_drv,
 			(unsigned) pci_dev->id.device_id);
 	if (rte_eal_process_type() == RTE_PROC_PRIMARY)
 		rte_free(eth_dev->data->dev_private);
+	eth_dev->attached = DEV_DISCONNECTED;
 	nb_ports--;
 	return diag;
 }
@@ -308,10 +336,22 @@ rte_eth_driver_register(struct eth_driver *eth_drv)
 	rte_eal_pci_register(&eth_drv->pci_drv);
 }
 
+static int
+rte_eth_dev_validate_port(uint8_t port_id)
+{
+	if (port_id >= RTE_MAX_ETHPORTS)
+		return DEV_INVALID;
+
+	if (rte_eth_devices[port_id].attached == DEV_CONNECTED)
+		return DEV_VALID;
+	else
+		return DEV_INVALID;
+}
+
 int
 rte_eth_dev_socket_id(uint8_t port_id)
 {
-	if (port_id >= nb_ports)
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID)
 		return -1;
 	return rte_eth_devices[port_id].pci_dev->numa_node;
 }
@@ -369,7 +409,7 @@ rte_eth_dev_rx_queue_start(uint8_t port_id, uint16_t rx_queue_id)
 	 * in a multi-process setup*/
 	PROC_PRIMARY_OR_ERR_RET(-E_RTE_SECONDARY);
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
 		return -EINVAL;
 	}
@@ -395,7 +435,7 @@ rte_eth_dev_rx_queue_stop(uint8_t port_id, uint16_t rx_queue_id)
 	 * in a multi-process setup*/
 	PROC_PRIMARY_OR_ERR_RET(-E_RTE_SECONDARY);
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
 		return -EINVAL;
 	}
@@ -421,7 +461,7 @@ rte_eth_dev_tx_queue_start(uint8_t port_id, uint16_t tx_queue_id)
 	 * in a multi-process setup*/
 	PROC_PRIMARY_OR_ERR_RET(-E_RTE_SECONDARY);
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
 		return -EINVAL;
 	}
@@ -447,7 +487,7 @@ rte_eth_dev_tx_queue_stop(uint8_t port_id, uint16_t tx_queue_id)
 	 * in a multi-process setup*/
 	PROC_PRIMARY_OR_ERR_RET(-E_RTE_SECONDARY);
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
 		return -EINVAL;
 	}
@@ -662,7 +702,7 @@ rte_eth_dev_configure(uint8_t port_id, uint16_t nb_rx_q, uint16_t nb_tx_q,
 	 * in a multi-process setup*/
 	PROC_PRIMARY_OR_ERR_RET(-E_RTE_SECONDARY);
 
-	if (port_id >= nb_ports || port_id >= RTE_MAX_ETHPORTS) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
 		return (-EINVAL);
 	}
@@ -847,7 +887,7 @@ rte_eth_dev_start(uint8_t port_id)
 	 * in a multi-process setup*/
 	PROC_PRIMARY_OR_ERR_RET(-E_RTE_SECONDARY);
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("Invalid port_id=%" PRIu8 "\n", port_id);
 		return (-EINVAL);
 	}
@@ -882,7 +922,7 @@ rte_eth_dev_stop(uint8_t port_id)
 	 * in a multi-process setup*/
 	PROC_PRIMARY_OR_RET();
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("Invalid port_id=%" PRIu8 "\n", port_id);
 		return;
 	}
@@ -910,7 +950,7 @@ rte_eth_dev_set_link_up(uint8_t port_id)
 	 * in a multi-process setup*/
 	PROC_PRIMARY_OR_ERR_RET(-E_RTE_SECONDARY);
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
 		return -EINVAL;
 	}
@@ -929,7 +969,7 @@ rte_eth_dev_set_link_down(uint8_t port_id)
 	 * in a multi-process setup*/
 	PROC_PRIMARY_OR_ERR_RET(-E_RTE_SECONDARY);
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
 		return -EINVAL;
 	}
@@ -948,7 +988,7 @@ rte_eth_dev_close(uint8_t port_id)
 	 * in a multi-process setup*/
 	PROC_PRIMARY_OR_RET();
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
 		return;
 	}
@@ -976,7 +1016,7 @@ rte_eth_rx_queue_setup(uint8_t port_id, uint16_t rx_queue_id,
 	 * in a multi-process setup*/
 	PROC_PRIMARY_OR_ERR_RET(-E_RTE_SECONDARY);
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
 		return (-EINVAL);
 	}
@@ -1049,7 +1089,7 @@ rte_eth_tx_queue_setup(uint8_t port_id, uint16_t tx_queue_id,
 	 * in a multi-process setup*/
 	PROC_PRIMARY_OR_ERR_RET(-E_RTE_SECONDARY);
 
-	if (port_id >= RTE_MAX_ETHPORTS || port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
 		return (-EINVAL);
 	}
@@ -1082,7 +1122,7 @@ rte_eth_promiscuous_enable(uint8_t port_id)
 {
 	struct rte_eth_dev *dev;
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
 		return;
 	}
@@ -1098,7 +1138,7 @@ rte_eth_promiscuous_disable(uint8_t port_id)
 {
 	struct rte_eth_dev *dev;
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
 		return;
 	}
@@ -1114,7 +1154,7 @@ rte_eth_promiscuous_get(uint8_t port_id)
 {
 	struct rte_eth_dev *dev;
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
 		return -1;
 	}
@@ -1128,7 +1168,7 @@ rte_eth_allmulticast_enable(uint8_t port_id)
 {
 	struct rte_eth_dev *dev;
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
 		return;
 	}
@@ -1144,7 +1184,7 @@ rte_eth_allmulticast_disable(uint8_t port_id)
 {
 	struct rte_eth_dev *dev;
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
 		return;
 	}
@@ -1160,7 +1200,7 @@ rte_eth_allmulticast_get(uint8_t port_id)
 {
 	struct rte_eth_dev *dev;
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
 		return -1;
 	}
@@ -1188,7 +1228,7 @@ rte_eth_link_get(uint8_t port_id, struct rte_eth_link *eth_link)
 {
 	struct rte_eth_dev *dev;
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
 		return;
 	}
@@ -1208,7 +1248,7 @@ rte_eth_link_get_nowait(uint8_t port_id, struct rte_eth_link *eth_link)
 {
 	struct rte_eth_dev *dev;
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
 		return;
 	}
@@ -1228,7 +1268,7 @@ rte_eth_stats_get(uint8_t port_id, struct rte_eth_stats *stats)
 {
 	struct rte_eth_dev *dev;
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
 		return;
 	}
@@ -1245,7 +1285,7 @@ rte_eth_stats_reset(uint8_t port_id)
 {
 	struct rte_eth_dev *dev;
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
 		return;
 	}
@@ -1266,7 +1306,7 @@ rte_eth_xstats_get(uint8_t port_id, struct rte_eth_xstats *xstats,
 	uint64_t val;
 	char *stats_ptr;
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
 		return -1;
 	}
@@ -1335,7 +1375,7 @@ rte_eth_xstats_reset(uint8_t port_id)
 {
 	struct rte_eth_dev *dev;
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
 		return;
 	}
@@ -1357,7 +1397,7 @@ set_queue_stats_mapping(uint8_t port_id, uint16_t queue_id, uint8_t stat_idx,
 {
 	struct rte_eth_dev *dev;
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
 		return -ENODEV;
 	}
@@ -1392,7 +1432,7 @@ rte_eth_dev_info_get(uint8_t port_id, struct rte_eth_dev_info *dev_info)
 {
 	struct rte_eth_dev *dev;
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
 		return;
 	}
@@ -1412,7 +1452,7 @@ rte_eth_macaddr_get(uint8_t port_id, struct ether_addr *mac_addr)
 {
 	struct rte_eth_dev *dev;
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
 		return;
 	}
@@ -1426,7 +1466,7 @@ rte_eth_dev_get_mtu(uint8_t port_id, uint16_t *mtu)
 {
 	struct rte_eth_dev *dev;
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
 		return (-ENODEV);
 	}
@@ -1442,7 +1482,7 @@ rte_eth_dev_set_mtu(uint8_t port_id, uint16_t mtu)
 	int ret;
 	struct rte_eth_dev *dev;
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
 		return (-ENODEV);
 	}
@@ -1462,7 +1502,7 @@ rte_eth_dev_vlan_filter(uint8_t port_id, uint16_t vlan_id, int on)
 {
 	struct rte_eth_dev *dev;
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
 		return (-ENODEV);
 	}
@@ -1487,7 +1527,7 @@ rte_eth_dev_set_vlan_strip_on_queue(uint8_t port_id, uint16_t rx_queue_id, int o
 {
 	struct rte_eth_dev *dev;
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
 		return (-ENODEV);
 	}
@@ -1509,7 +1549,7 @@ rte_eth_dev_set_vlan_ether_type(uint8_t port_id, uint16_t tpid)
 {
 	struct rte_eth_dev *dev;
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
 		return (-ENODEV);
 	}
@@ -1529,7 +1569,7 @@ rte_eth_dev_set_vlan_offload(uint8_t port_id, int offload_mask)
 	int mask = 0;
 	int cur, org = 0;
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
 		return (-ENODEV);
 	}
@@ -1574,7 +1614,7 @@ rte_eth_dev_get_vlan_offload(uint8_t port_id)
 	struct rte_eth_dev *dev;
 	int ret = 0;
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
 		return (-ENODEV);
 	}
@@ -1598,7 +1638,7 @@ rte_eth_dev_set_vlan_pvid(uint8_t port_id, uint16_t pvid, int on)
 {
 	struct rte_eth_dev *dev;
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
 		return (-ENODEV);
 	}
@@ -1616,7 +1656,7 @@ rte_eth_dev_fdir_add_signature_filter(uint8_t port_id,
 {
 	struct rte_eth_dev *dev;
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
 		return (-ENODEV);
 	}
@@ -1650,7 +1690,7 @@ rte_eth_dev_fdir_update_signature_filter(uint8_t port_id,
 {
 	struct rte_eth_dev *dev;
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
 		return (-ENODEV);
 	}
@@ -1684,7 +1724,7 @@ rte_eth_dev_fdir_remove_signature_filter(uint8_t port_id,
 {
 	struct rte_eth_dev *dev;
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
 		return (-ENODEV);
 	}
@@ -1715,7 +1755,7 @@ rte_eth_dev_fdir_get_infos(uint8_t port_id, struct rte_eth_fdir *fdir)
 {
 	struct rte_eth_dev *dev;
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
 		return (-ENODEV);
 	}
@@ -1740,7 +1780,7 @@ rte_eth_dev_fdir_add_perfect_filter(uint8_t port_id,
 {
 	struct rte_eth_dev *dev;
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
 		return (-ENODEV);
 	}
@@ -1780,7 +1820,7 @@ rte_eth_dev_fdir_update_perfect_filter(uint8_t port_id,
 {
 	struct rte_eth_dev *dev;
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
 		return (-ENODEV);
 	}
@@ -1818,7 +1858,7 @@ rte_eth_dev_fdir_remove_perfect_filter(uint8_t port_id,
 {
 	struct rte_eth_dev *dev;
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
 		return (-ENODEV);
 	}
@@ -1854,7 +1894,7 @@ rte_eth_dev_fdir_set_masks(uint8_t port_id, struct rte_fdir_masks *fdir_mask)
 {
 	struct rte_eth_dev *dev;
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
 		return (-ENODEV);
 	}
@@ -1874,7 +1914,7 @@ rte_eth_dev_flow_ctrl_get(uint8_t port_id, struct rte_eth_fc_conf *fc_conf)
 {
 	struct rte_eth_dev *dev;
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
 		return (-ENODEV);
 	}
@@ -1890,7 +1930,7 @@ rte_eth_dev_flow_ctrl_set(uint8_t port_id, struct rte_eth_fc_conf *fc_conf)
 {
 	struct rte_eth_dev *dev;
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
 		return (-ENODEV);
 	}
@@ -1910,7 +1950,7 @@ rte_eth_dev_priority_flow_ctrl_set(uint8_t port_id, struct rte_eth_pfc_conf *pfc
 {
 	struct rte_eth_dev *dev;
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
 		return (-ENODEV);
 	}
@@ -2019,7 +2059,7 @@ rte_eth_dev_rss_reta_query(uint8_t port_id,
 	struct rte_eth_dev *dev;
 	int ret;
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
 		return -ENODEV;
 	}
@@ -2040,7 +2080,7 @@ rte_eth_dev_rss_hash_update(uint8_t port_id, struct rte_eth_rss_conf *rss_conf)
 	struct rte_eth_dev *dev;
 	uint16_t rss_hash_protos;
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
 		return (-ENODEV);
 	}
@@ -2062,7 +2102,7 @@ rte_eth_dev_rss_hash_conf_get(uint8_t port_id,
 {
 	struct rte_eth_dev *dev;
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
 		return (-ENODEV);
 	}
@@ -2077,7 +2117,7 @@ rte_eth_dev_udp_tunnel_add(uint8_t port_id,
 {
 	struct rte_eth_dev *dev;
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
 		return -ENODEV;
 	}
@@ -2103,7 +2143,7 @@ rte_eth_dev_udp_tunnel_delete(uint8_t port_id,
 {
 	struct rte_eth_dev *dev;
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
 		return -ENODEV;
 	}
@@ -2128,7 +2168,7 @@ rte_eth_led_on(uint8_t port_id)
 {
 	struct rte_eth_dev *dev;
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
 		return (-ENODEV);
 	}
@@ -2143,7 +2183,7 @@ rte_eth_led_off(uint8_t port_id)
 {
 	struct rte_eth_dev *dev;
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
 		return (-ENODEV);
 	}
@@ -2183,7 +2223,7 @@ rte_eth_dev_mac_addr_add(uint8_t port_id, struct ether_addr *addr,
 	int index;
 	uint64_t pool_mask;
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
 		return (-ENODEV);
 	}
@@ -2234,7 +2274,7 @@ rte_eth_dev_mac_addr_remove(uint8_t port_id, struct ether_addr *addr)
 	struct rte_eth_dev *dev;
 	int index;
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
 		return (-ENODEV);
 	}
@@ -2268,7 +2308,7 @@ rte_eth_dev_set_vf_rxmode(uint8_t port_id,  uint16_t vf,
 	struct rte_eth_dev *dev;
 	struct rte_eth_dev_info dev_info;
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("set VF RX mode:Invalid port_id=%d\n",
 				port_id);
 		return (-ENODEV);
@@ -2323,7 +2363,7 @@ rte_eth_dev_uc_hash_table_set(uint8_t port_id, struct ether_addr *addr,
 	int ret;
 	struct rte_eth_dev *dev;
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("unicast hash setting:Invalid port_id=%d\n",
 			port_id);
 		return (-ENODEV);
@@ -2376,7 +2416,7 @@ rte_eth_dev_uc_all_hash_table_set(uint8_t port_id, uint8_t on)
 {
 	struct rte_eth_dev *dev;
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("unicast hash setting:Invalid port_id=%d\n",
 			port_id);
 		return (-ENODEV);
@@ -2395,7 +2435,7 @@ rte_eth_dev_set_vf_rx(uint8_t port_id,uint16_t vf, uint8_t on)
 	struct rte_eth_dev *dev;
 	struct rte_eth_dev_info dev_info;
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
 		return (-ENODEV);
 	}
@@ -2421,7 +2461,7 @@ rte_eth_dev_set_vf_tx(uint8_t port_id,uint16_t vf, uint8_t on)
 	struct rte_eth_dev *dev;
 	struct rte_eth_dev_info dev_info;
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("set pool tx:Invalid port_id=%d\n", port_id);
 		return (-ENODEV);
 	}
@@ -2446,7 +2486,7 @@ rte_eth_dev_set_vf_vlan_filter(uint8_t port_id, uint16_t vlan_id,
 {
 	struct rte_eth_dev *dev;
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("VF VLAN filter:invalid port id=%d\n",
 				port_id);
 		return (-ENODEV);
@@ -2477,7 +2517,7 @@ int rte_eth_set_queue_rate_limit(uint8_t port_id, uint16_t queue_idx,
 	struct rte_eth_dev_info dev_info;
 	struct rte_eth_link link;
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("set queue rate limit:invalid port id=%d\n",
 				port_id);
 		return -ENODEV;
@@ -2514,7 +2554,7 @@ int rte_eth_set_vf_rate_limit(uint8_t port_id, uint16_t vf, uint16_t tx_rate,
 	if (q_msk == 0)
 		return 0;
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("set VF rate limit:invalid port id=%d\n",
 				port_id);
 		return -ENODEV;
@@ -2548,7 +2588,7 @@ rte_eth_mirror_rule_set(uint8_t port_id,
 {
 	struct rte_eth_dev *dev = &rte_eth_devices[port_id];
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
 		return (-ENODEV);
 	}
@@ -2589,7 +2629,7 @@ rte_eth_mirror_rule_reset(uint8_t port_id, uint8_t rule_id)
 {
 	struct rte_eth_dev *dev = &rte_eth_devices[port_id];
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
 		return (-ENODEV);
 	}
@@ -2614,7 +2654,7 @@ rte_eth_rx_burst(uint8_t port_id, uint16_t queue_id,
 {
 	struct rte_eth_dev *dev;
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
 		return 0;
 	}
@@ -2634,7 +2674,7 @@ rte_eth_tx_burst(uint8_t port_id, uint16_t queue_id,
 {
 	struct rte_eth_dev *dev;
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
 		return 0;
 	}
@@ -2654,7 +2694,7 @@ rte_eth_rx_queue_count(uint8_t port_id, uint16_t queue_id)
 {
 	struct rte_eth_dev *dev;
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
 		return 0;
 	}
@@ -2668,7 +2708,7 @@ rte_eth_rx_descriptor_done(uint8_t port_id, uint16_t queue_id, uint16_t offset)
 {
 	struct rte_eth_dev *dev;
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
 		return (-ENODEV);
 	}
@@ -2689,7 +2729,7 @@ rte_eth_dev_callback_register(uint8_t port_id,
 
 	if (!cb_fn)
 		return (-EINVAL);
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
 		return (-EINVAL);
 	}
@@ -2729,7 +2769,7 @@ rte_eth_dev_callback_unregister(uint8_t port_id,
 
 	if (!cb_fn)
 		return (-EINVAL);
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
 		return (-EINVAL);
 	}
@@ -2789,7 +2829,7 @@ int rte_eth_dev_bypass_init(uint8_t port_id)
 {
 	struct rte_eth_dev *dev;
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
 		return (-ENODEV);
 	}
@@ -2809,7 +2849,7 @@ rte_eth_dev_bypass_state_show(uint8_t port_id, uint32_t *state)
 {
 	struct rte_eth_dev *dev;
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
 		return (-ENODEV);
 	}
@@ -2828,7 +2868,7 @@ rte_eth_dev_bypass_state_set(uint8_t port_id, uint32_t *new_state)
 {
 	struct rte_eth_dev *dev;
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
 		return (-ENODEV);
 	}
@@ -2848,7 +2888,7 @@ rte_eth_dev_bypass_event_show(uint8_t port_id, uint32_t event, uint32_t *state)
 {
 	struct rte_eth_dev *dev;
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
 		return (-ENODEV);
 	}
@@ -2868,7 +2908,7 @@ rte_eth_dev_bypass_event_store(uint8_t port_id, uint32_t event, uint32_t state)
 {
 	struct rte_eth_dev *dev;
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
 		return (-ENODEV);
 	}
@@ -2888,7 +2928,7 @@ rte_eth_dev_wd_timeout_store(uint8_t port_id, uint32_t timeout)
 {
 	struct rte_eth_dev *dev;
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
 		return (-ENODEV);
 	}
@@ -2908,7 +2948,7 @@ rte_eth_dev_bypass_ver_show(uint8_t port_id, uint32_t *ver)
 {
 	struct rte_eth_dev *dev;
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
 		return (-ENODEV);
 	}
@@ -2928,7 +2968,7 @@ rte_eth_dev_bypass_wd_timeout_show(uint8_t port_id, uint32_t *wd_timeout)
 {
 	struct rte_eth_dev *dev;
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
 		return (-ENODEV);
 	}
@@ -2948,7 +2988,7 @@ rte_eth_dev_bypass_wd_reset(uint8_t port_id)
 {
 	struct rte_eth_dev *dev;
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
 		return (-ENODEV);
 	}
@@ -2970,7 +3010,7 @@ rte_eth_dev_add_syn_filter(uint8_t port_id,
 {
 	struct rte_eth_dev *dev;
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
 		return -ENODEV;
 	}
@@ -2985,7 +3025,7 @@ rte_eth_dev_remove_syn_filter(uint8_t port_id)
 {
 	struct rte_eth_dev *dev;
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
 		return -ENODEV;
 	}
@@ -3004,7 +3044,7 @@ rte_eth_dev_get_syn_filter(uint8_t port_id,
 	if (filter == NULL || rx_queue == NULL)
 		return -EINVAL;
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
 		return -ENODEV;
 	}
@@ -3020,7 +3060,7 @@ rte_eth_dev_add_ethertype_filter(uint8_t port_id, uint16_t index,
 {
 	struct rte_eth_dev *dev;
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
 		return -ENODEV;
 	}
@@ -3041,7 +3081,7 @@ rte_eth_dev_remove_ethertype_filter(uint8_t port_id,  uint16_t index)
 {
 	struct rte_eth_dev *dev;
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
 		return -ENODEV;
 	}
@@ -3060,7 +3100,7 @@ rte_eth_dev_get_ethertype_filter(uint8_t port_id, uint16_t index,
 	if (filter == NULL || rx_queue == NULL)
 		return -EINVAL;
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
 		return -ENODEV;
 	}
@@ -3077,7 +3117,7 @@ rte_eth_dev_add_2tuple_filter(uint8_t port_id, uint16_t index,
 {
 	struct rte_eth_dev *dev;
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
 		return -ENODEV;
 	}
@@ -3099,7 +3139,7 @@ rte_eth_dev_remove_2tuple_filter(uint8_t port_id, uint16_t index)
 {
 	struct rte_eth_dev *dev;
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
 		return -ENODEV;
 	}
@@ -3118,7 +3158,7 @@ rte_eth_dev_get_2tuple_filter(uint8_t port_id, uint16_t index,
 	if (filter == NULL || rx_queue == NULL)
 		return -EINVAL;
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
 		return -ENODEV;
 	}
@@ -3134,7 +3174,7 @@ rte_eth_dev_add_5tuple_filter(uint8_t port_id, uint16_t index,
 {
 	struct rte_eth_dev *dev;
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
 		return -ENODEV;
 	}
@@ -3157,7 +3197,7 @@ rte_eth_dev_remove_5tuple_filter(uint8_t port_id, uint16_t index)
 {
 	struct rte_eth_dev *dev;
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
 		return -ENODEV;
 	}
@@ -3176,7 +3216,7 @@ rte_eth_dev_get_5tuple_filter(uint8_t port_id, uint16_t index,
 	if (filter == NULL || rx_queue == NULL)
 		return -EINVAL;
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
 		return -ENODEV;
 	}
@@ -3193,7 +3233,7 @@ rte_eth_dev_add_flex_filter(uint8_t port_id, uint16_t index,
 {
 	struct rte_eth_dev *dev;
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
 		return -ENODEV;
 	}
@@ -3208,7 +3248,7 @@ rte_eth_dev_remove_flex_filter(uint8_t port_id, uint16_t index)
 {
 	struct rte_eth_dev *dev;
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
 		return -ENODEV;
 	}
@@ -3227,7 +3267,7 @@ rte_eth_dev_get_flex_filter(uint8_t port_id, uint16_t index,
 	if (filter == NULL || rx_queue == NULL)
 		return -EINVAL;
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
 		return -ENODEV;
 	}
@@ -3243,7 +3283,7 @@ rte_eth_dev_filter_supported(uint8_t port_id, enum rte_filter_type filter_type)
 {
 	struct rte_eth_dev *dev;
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
 		return -ENODEV;
 	}
@@ -3260,7 +3300,7 @@ rte_eth_dev_filter_ctrl(uint8_t port_id, enum rte_filter_type filter_type,
 {
 	struct rte_eth_dev *dev;
 
-	if (port_id >= nb_ports) {
+	if (rte_eth_dev_validate_port(port_id) == DEV_INVALID) {
 		PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
 		return -ENODEV;
 	}
diff --git a/lib/librte_ether/rte_ethdev.h b/lib/librte_ether/rte_ethdev.h
index f66805d..257de86 100644
--- a/lib/librte_ether/rte_ethdev.h
+++ b/lib/librte_ether/rte_ethdev.h
@@ -1565,6 +1565,7 @@ struct rte_eth_dev {
 	struct eth_dev_ops *dev_ops;    /**< Functions exported by PMD */
 	struct rte_pci_device *pci_dev; /**< PCI info. supplied by probing */
 	struct rte_eth_dev_cb_list callbacks; /**< User application callbacks */
+	uint8_t attached; /**< Flag indicating the port is attached */
 };
 
 struct rte_eth_dev_sriov {
@@ -1630,6 +1631,10 @@ extern struct rte_eth_dev rte_eth_devices[];
  * initialized by the [matching] Ethernet driver during the PCI probing phase.
  * All devices whose port identifier is in the range
  * [0,  rte_eth_dev_count() - 1] can be operated on by network applications.
+ * immediately after invoking rte_eal_init().
+ * If the application unplugs a port using hotplug function, The enabled port
+ * numbers may be noncontiguous. In the case, the applications need to manage
+ * enabled port by themselves.
  *
  * @return
  *   - The total number of usable Ethernet devices.
