def get_interfaces_counters(self):
raise NotImplementedError<EOL>
Returns a dictionary of dictionaries where the first key is an interface name and the
inner dictionary contains the following keys:

    * tx_errors (int)
    * rx_errors (int)
    * tx_discards (int)
    * rx_discards (int)
    * tx_octets (int)
    * rx_octets (int)
    * tx_unicast_packets (int)
    * rx_unicast_packets (int)
    * tx_multicast_packets (int)
    * rx_multicast_packets (int)
    * tx_broadcast_packets (int)
    * rx_broadcast_packets (int)

Example::

    {
        u'Ethernet2': {
            'tx_multicast_packets': 699,
            'tx_discards': 0,
            'tx_octets': 88577,
            'tx_errors': 0,
            'rx_octets': 0,
            'tx_unicast_packets': 0,
            'rx_errors': 0,
            'tx_broadcast_packets': 0,
            'rx_multicast_packets': 0,
            'rx_broadcast_packets': 0,
            'rx_discards': 0,
            'rx_unicast_packets': 0
        },
        u'Management1': {
             'tx_multicast_packets': 0,
             'tx_discards': 0,
             'tx_octets': 159159,
             'tx_errors': 0,
             'rx_octets': 167644,
             'tx_unicast_packets': 1241,
             'rx_errors': 0,
             'tx_broadcast_packets': 0,
             'rx_multicast_packets': 0,
             'rx_broadcast_packets': 80,
             'rx_discards': 0,
             'rx_unicast_packets': 0
        },
        u'Ethernet1': {
             'tx_multicast_packets': 293,
             'tx_discards': 0,
             'tx_octets': 38639,
             'tx_errors': 0,
             'rx_octets': 0,
             'tx_unicast_packets': 0,
             'rx_errors': 0,
             'tx_broadcast_packets': 0,
             'rx_multicast_packets': 0,
             'rx_broadcast_packets': 0,
             'rx_discards': 0,
             'rx_unicast_packets': 0
        }
    }