Information from a show interface command

 Information from a show interface command

Field	Meaning
Up/down	Whether the interface is up and configured. If the interface is administratively down, the shutdown command has been applied to this interface. If the interface is down, it is not receiving any signal from the attached network cable.
Line protocol	Whether the encapsulation protocol is up or down for this interface. If your interface is up but the line protocol is down, check the encapsulation or see if the line has been unplugged.
Hardware	The type of interface (serial, Ethernet, etc.).
Internet address	The IP address and subnet mask for this interface.
MTU	The Maximum Transmission Unit for this interface (the maximum frame/packet size).
BW	The bit rate in kbps (default is 1544 for serial, 10000 for Ethernet). This value is actually the setting from the interface's bandwidth command, which is used in route metric calculations but has no other impact on the router. In particular, this value has nothing to do with the actual speed at which data is transferred.
DLY	The expected delay for a packet traversing this interface. Like the bandwidth, this parameter is used only for IGRP/EIGRP route metric calculations. Its value can be set with the delay interface command.
Rely	The reliability of this link, as a number between 1 and 255. The value 255/255 indicates that the link is 100% reliable.
Load	The traffic load on the segment, as a number between 1 and 255. The value 255/255 indicates that the link is at 100% of capacity. 1/255 is the lowest value.
Encapsulation	The encapsulation type for this link. For serial links, the encapsulation might be PPP or HDLC. For Ethernet, it might be ARPA.
Loopback	Whether the interface is in the loopback state. If you cannot send packets across your link, you may have loopback set.
Keepalives	Whether keepalives are active on this link.
Last input/last output	How long it has been since a packet was received or sent on this interface. This field is not an actual time value, but the number of hours, minutes, and seconds since the packet was received or sent. If the time exceeds 24 hours, the field overflows and asterisks are printed.
Output hang	The time since this interface was last reset because of a transmission that took too long to complete. If the time exceeds 24 hours, the field overflows and asterisks are printed.
Queue	The number of packets in both the input and output queues. The number is in the format "number in queue/max size of queue, number of drops".
5 minute	The five-minute average input and output rate. The rate is given in both bits per second and packets per second over the last five minutes.
Packets input	Number of successful error-free packets this interface has received.
Bytes input	Number of successful error-free bytes this interface has received.
Broadcasts	Number of multicast or broadcast packets this interface has received.
Runts	Number of packets this interface threw away because they were smaller than the minimum packet size.
Giants	Number of packets this interface threw away because they were larger than the maximum packet size.
Input error	Total number of errors encountered by this interface. These errors can include runts, giants, CRC errors, overruns, ignored packets, aborts, buffer overflows, and frame errors.
CRC	The number of checksum failures encountered by this interface. A checksum failure occurs when the calculated checksum does not match the checksum sent by the sending device. Lots of CRC errors mixed with a low number of collisions on an Ethernet interface is an indicator of excessive noise, which points to cable issues.
Frame	The number of frame errors encountered by this interface. These occur when a packet that is malformed or does not contain the correct number of bytes is delivered to the interface.
Overruns	The number of overrun errors within this interface. This occurs when the low-level device driver fails to read a byte before the serialization hardware completes receiving the next byte.
Ignored	The number of packets ignored by this interface. This occurs when the internal buffers are full and the interface ignores incoming packets because it has no place to store them.
Abort	The number of aborts on this interface. Occurs because of a timing problem between the router and serial device.
Packets output	The total number of packets this interface has transmitted.
Bytes output	The total number of bytes this interface has transmitted.
Underruns	The number of underrun errors on this interface. Occurs when the low-level device driver fails to provide the next byte to be serialized before the previous one has been completely transmitted.
Output errors	The number of errors that occurred when this interface tried to transmit.
Collisions	The number of times two hosts sent a packet at the same time; a small number is normal.
Late collisions	This number should always be 0 on a properly configured network. If you see these, suspect a hardware problem.
Restarts	The total number of times this interface reset due to errors. Not shown in the output above.
Carrier transitions	The total number of times this interface has changed state because it lost the carrier signal. Not shown in the output above.