> +According to loopback mode, setup loopback link or not.
> +If loopback mode is setted, packets will be sent to rx_q from tx_q directly.
> +Else if loopback mode is disabled, packets will sent to peer port from tx_q.
> +Loopback mode can be used to support testing task.
> +Two 10Gb/25Gb/40Gb Ethernet ports of the DUT are directly connected and link is up.
> +packet, and "Test OK" is printed out.
> +The peer port can't receive any packet.
> +There is not "Test OK" presented.
> +The peer port can receive all the 32 packets.