5.1.7. Interface status and statistics

The state of the configured interfaces is indicated by leds of different colors before the name of the interface ( Green — Up, Red — Down, Blue — Unknown). The state of the interface is automatically updated periodically. The update frequency can be configured in Edit > Preferences > General > Program status. Status update can also be requested manually from the local menu of the interface. To do this, select the interface, right-click on it and select Refresh State. Hovering the mouse over an interface displays a tooltip with status information and detailed statistics about the interface. The following status information is displayed:

  • State: Status of the interface. Possible values: Up, Down, Unknown.

  • qdisc: Queuing discipline. For details, see the Traffic Control manual pages (man tc).

  • flags: Flags applicable to the interface. Possible values: UP, BROADCAST, MULTICAST, PROMISC, NOARP, ALLMULTI, LOOPBACK.

  • mtu: Maximum Transmission Unit (MTU): the maximum size of a packet (in bytes) allowed to be sent from the interface.

The statistics about the traffic handled by the interface is divided into Received and Sent sections, relevant for the received/sent packets, respectively.

  • Errors: Number of errors encountered.

  • Bytes: Amount of data received.

  • Packets: Number of packets received.

  • Mcast: Number of received multicast packets.

  • Dropped: Number of dropped packets.

  • Overruns: Number of overruns. Overruns usually occur when packets come in faster than the kernel can service the last interrupt.

  • Collisions: Number of collisions encountered.

  • Bytes: Amount of data sent.

  • Packets: Number of packets sent.

  • Errors: Number of errors encountered.

  • Dropped: Number of dropped packets.

  • Carrier: The number of carrier losses detected by the device driver. Carrier losses are usually the sign of physical errors on the network.