O que significam os números entre colchetes da saída ethtool?

Question

Estou analisando as estatísticas da NIC e não consigo encontrar informações sobre esses números: [0], [1]. [7] como aqui:

[root@machine-1 ~]# ethtool -S enp21s0f0
NIC statistics:
     [0]: rx_bytes: 23048043995115
     [0]: rx_ucast_packets: 15462207866
     [0]: rx_mcast_packets: 0
     [0]: rx_bcast_packets: 497867
     [0]: rx_discards: 182348870
     [0]: rx_phy_ip_err_discards: 0
     [0]: rx_skb_alloc_discard: 0
     [0]: rx_csum_offload_errors: 0
     [0]: tx_exhaustion_events: 0
     [0]: tx_bytes: 252752492903
     [0]: tx_ucast_packets: 3121234510
     [0]: tx_mcast_packets: 1193
     [0]: tx_bcast_packets: 7
     [0]: tpa_aggregations: 3083926520
     [0]: tpa_aggregated_frames: 14764082568
     [0]: tpa_bytes: 22280531307898
     [0]: driver_filtered_tx_pkt: 0
     [1]: rx_bytes: 22967624549688
     [1]: rx_ucast_packets: 15411735203
     [1]: rx_mcast_packets: 3941
     [1]: rx_bcast_packets: 0
     [1]: rx_discards: 179569626
     [1]: rx_phy_ip_err_discards: 0
     [1]: rx_skb_alloc_discard: 0
     [1]: rx_csum_offload_errors: 0
     [1]: tx_exhaustion_events: 0
     [1]: tx_bytes: 251125804240
     [1]: tx_ucast_packets: 3098417333
     [1]: tx_mcast_packets: 2
     [1]: tx_bcast_packets: 0
     [1]: tpa_aggregations: 3074727449
     [1]: tpa_aggregated_frames: 14713070673
     [1]: tpa_bytes: 22203188664170
     [1]: driver_filtered_tx_pkt: 0
...

Mas descobri que, para a mensagem ARP, apenas os valores [0] são aumentados. Então, o que eles significam?