display interface loopback

Current state

Physical layer state of the loopback interface:

• UP—The loopback interface can receive and transmit packets.

• Administratively DOWN—The interface was manually shut down by using the shutdown command.

Line protocol state

Data link layer protocol state of the interface. UP (spoofing) means that the data link layer protocol state of the interface is up, but the link is an on-demand link or is not present.

Description

Description string of the interface.

Bandwidth

Expected bandwidth of the interface.

Maximum transmission unit

MTU of the interface.

Internet protocol processing: Disabled

Indicates that the interface cannot process Layer 3 packets (displayed when the interface is not configured with an IP address).

Internet address is 1.1.1.1/32 (primary)

Primary IP address of the interface (displayed when the interface is configured with a primary IP address).

Physical: Loopback

The physical type of the interface is loopback.

Last clearing of counters

Time when statistics on the logical interface were last cleared by using the reset counters interface command.

If the statistics of the interface have never been cleared by using the reset counters interface command since the device started, this field displays Never.

Last 300 seconds input rate: 0 bytes/sec, 0 bits/sec, 0 packets/sec

Average input rate during the last 300 seconds:

• bytes/sec—Average number of bytes received per second.

• bits/sec—Average number of bits received per second.

• packets/sec—Average number of packets received per second.

Last 300 seconds output rate: 0 bytes/sec, 0 bits/sec, 0 packets/sec

Average output rate over the last 300 seconds:

• bytes/sec—Average number of bytes sent per second.

• bits/sec—Average number of bits sent per second.

• packets/sec—Average number of packets sent per second.

Input: 0 packets, 0 bytes, 0 drops

Total number and size (in bytes) of incoming packets of the interface and the number of dropped packets.

Output: 0 packets, 0 bytes, 0 drops

Total number and size (in bytes) of outgoing packets of the interface and the number of dropped packets.

Brief information on interfaces in route mode

Brief information about loopback interfaces.

Link: ADM - administratively down; Stby - standby

Explains the Link field values:

• ADM—The interface has been shut down by the network administrator. To recover its physical layer state, run the undo shutdown command.

• Stby—The interface is a standby interface.

Protocol: (s) - spoofing

Explains the Protocol field value.

(s)—Represents spoofing. If the data link layer protocol of an interface is up, but the link is an on-demand link or is not present, the Protocol field displays UP(s). This attribute is typical of interface Null 0, Inloopback 0, and loopback interfaces.

Interface

Interface name.

Link

Physical layer state of the interface:

• UP—The interface is up.

• DOWN—The interface is physically down.

• ADM—The interface has been administratively shut down. To recover its physical state, run the undo shutdown command.

• Stby—The interface is a standby interface.

Protocol

Data link layer protocol state of the interface.

Primary IP

IP address of the interface.

Description

Interface description configured by using the description command. If the description keyword is not specified in the display interface brief command, the Description field allows a maximum of 27 characters. If the description keyword is specified in the display interface brief command, the field displays the complete interface description.

Cause

Cause of the interface down event. If the interface has been shut down by using the shutdown command, this field displays Administratively. To restore the physical state of the interface, execute the undo shutdown command.