NIC statistics explanation (ethtool -S eth1)

tx_packets: Trasmitted packets rx_packets: Received packets tx_errors: Trasmission errors rx_errors: Received errors rx_missed: Recieved misses align_errors: Received alignment errors tx_single_collisions: Trasmitted singular collisions tx_multi_collisions: Trasmitted multiple collisions unicast: Received unicast broadcast: Received broadcast multicast: Recieved multicast tx_aborted: Aborted trasmissions tx_underrun: Aborted underruns 

For a better understanding of the terminology, see this message:

An underrun error on an ethernet is a transmission error. The way most ethernet chips transmit packets is that they DMA packet data from memory into their internal transmit fifo for sending. They do not ususally load the entire packet into the fifo before transmitting (some may have fifos smaller than the max. pkt size), so they go grab the data as they need it - there is usually a low-water mark in the fifo which triggers this.

A transmit fifo underrun will occur if the ethernet chip cannot obtain the local bus in order to get more packet data for the fifo, and the fifo becomes empty before the end of the packet has been reached.

So:

• multicast - imagine trying to communicate from one system to a select number of others
• broadcast - imagine trying to communicate from one system to all other systems
• collision - imagine what will happen when two system are trying to communicate with one another simultaneously they end up blocking one another
• alignment - imagine you can only communicate in specific units. Words of 4 characters at a time only. If there is a mis-alignment of characters systems can't communicate with one another. It's the same here.

If you're interested, it may be worth taking a look at the following.

• Ethernet Error Descriptions
• ethtool.c