Null Interface Commands

This module provides command line interface (CLI) commands for configuring null interfaces on the Cisco XR 12000 Series Router.

interface null 0

To enter null0 interface configuration mode, use the interface null 0 command in global configuration mode.

interface null 0

Syntax Description

This command has no keywords or arguments.

Command Default

No default behavior or values

Command Modes

Global configuration

Command History

Release

Modification

Release 3.2

This command was first supported.

Usage Guidelines

When you issue the interface null 0 command in global configuration mode, the CLI prompt changes to “config-null0,” indicating that you have entered interface configuration mode for the null interface. In the following sample output, the question mark (?) online help function displays all the commands available under the interface configuration mode for the null interface: 

RP/0/0/CPU0:router(config)# interface null 0
RP/0/0/CPU0:router(config-null0)#?

  commit    Commit the configuration changes to running
  describe  Describe a command without taking real actions
  do        Run an exec command
  exit      Exit from this submode
  no        Negate a command or set its defaults
  show      Show contents of configuration

Task ID

Task ID

Operations

interface

read, write

Examples

This example shows how to enter null0 interface configuration mode: 

RP/0/0/CPU0:router(config)# interface null 0
RP/0/0/CPU0:router(config-null0)#

show controllers null interface

To display null interface counters, use the show controllers null interface command in EXEC mode.

show controllers null interface

Syntax Description

This command has no keywords or arguments.

Command Default

No default behavior or values

Command Modes

EXEC

Command History

Release

Modification

Release 3.2

This command was introduced.

Usage Guidelines

Task ID

Task ID

Operations

interface

read

sysmgr

read

Examples

The following is sample output from the show controllers null interface command, which displays null interface counters: 

RP/0/0/CPU0:router# show controllers null interface

Null interface:
name     : Null0
handle   : 0x00080010
rx_count : 0
tx_count : 0
drops    : 0
Table 1 show controllers null interface Field Descriptions

Field

Description

name

Interface whose controller information is displayed.

handle

Number that identifies the caps node that hosts the node whose controller information is displayed.

rx_count

Total number of packets currently received by the interface.

tx_count

Total number of packets currently transmitted by the interface.

drops

Total number of packets dropped by the interface.

Related Commands

Command

Description

show interfaces null0

Displays null0 interfaces.  

show interfaces null0

To display null0 interfaces, use the show interfaces null0 command with optional keywords in EXEC mode.

show interfaces null0 [ accounting rates | brief | description | detail ] [ location node-id ]

Syntax Description

accounting

Shows interface accounting option.

rates

Shows interface accounting (input/output) rates.

brief

Shows interface information in condensed format.

description

Describes interface.

detail

Shows interface information in detail.

location node-id

Specifies a fully qualified interface location.

Command Default

No default behavior or values

Command Modes

EXEC

Command History

Release

Modification

Release 3.6.0

This command variant was added to the existing show interfaces command.

Usage Guidelines

The show interfaces null0 command displays statistics about null interfaces. When no keywords are specified, information for all null interfaces is displayed.

Task ID

Task ID

Operations

interface

read

Examples

The following example shows how to use the show interfaces null0 command: 

RP/0/0/CPU0:router# show interfaces null0

Null0 is up, line protocol is up 
  Interface state transitions: 0
  Hardware is Null interface
  Internet address is Unknown
  MTU 1500 bytes, BW Unknown
     reliability 255/255, txload Unknown, rxload Unknown
  Encapsulation Null,  loopback not set,
  Last clearing of "show interface" counters never
  5 minute input rate 0 bits/sec, 0 packets/sec
  5 minute output rate 0 bits/sec, 0 packets/sec
     0 packets input, 0 bytes, 0 total input drops
     0 drops for unrecognized upper-level protocol
     Received 0 broadcast packets, 0 multicast packets
     0 packets output, 0 bytes, 0 total output drops
     Output 0 broadcast packets, 0 multicast packets