def METHOD_NAME(test_sub_port, testbed_params, ptfadapter):
    """Generate Ethernet packets that will be sent to test sub port to verify L2 forwarding."""
    def _simple_tagged_eth_packet(eth_dst, eth_src, vlanid):
        pkt = Ether(src=eth_src, dst=eth_dst)
        pkt /= Dot1Q(vlan=vlanid)
        pkt /= ("0" * (60 - len(pkt)) + PACKET_PAYLOAD_FINGERPRINT)
        return pkt
    # first packet has a dummy MAC dst MAC, second packet has a broadcast dst MAC
    eth_dsts = ["00:01:02:03:04:05", "ff:ff:ff:ff:ff:ff"]
    # select the MAC address of a different sub port's neighbor server port as third packet dst MAC
    dst_sub_port = [_ for _ in testbed_params if testbed_params[test_sub_port]["port"] not in _][0]
    dst_port_neighbor_ptf_index = testbed_params[dst_sub_port]["neighbor_ptf_index"]
    dst_port_ptf_mac = ptfadapter.dataplane.get_mac(0, dst_port_neighbor_ptf_index)
    eth_dsts.append(dst_port_ptf_mac)
    # generate test packets
    test_port_neighbor_ptf_index = testbed_params[test_sub_port]["neighbor_ptf_index"]
    test_port_vlan_id = testbed_params[test_sub_port]["vlanid"]
    eth_src = ptfadapter.dataplane.get_mac(0, test_port_neighbor_ptf_index)
    packets = []
    for eth_dst in eth_dsts:
        packets.append(_simple_tagged_eth_packet(eth_src, eth_dst, int(test_port_vlan_id)))
    return packets