Table Of Contents

Null Interface Commands on Cisco IOS XR Software

interface null 0

show controllers null interface

show interfaces null0

Null Interface Commands on Cisco IOS XR Software

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This module describes the Cisco IOS XR commands used to configure null interfaces.

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 arguments or keywords.

Defaults

No default behavior or values

Command Modes

Global configuration

Command History

Release	Modification
Release 2.0	This command was introduced on the Cisco CRS-1.
Release 3.0	No modification.
Release 3.2	This command was first supported on the Cisco XR 12000 Series Router.
Release 3.3.0	No modification.
Release 3.4.0	No modification.
Release 3.5.0	No modification.
Release 3.6.0	No modification.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes the proper task IDs. For detailed information about user groups and task IDs, see the Configuring AAA Services on Cisco IOS XR Software module of the Cisco IOS XR System Security Configuration Guide.

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/RP0/CPU0:router(config)# interface null 0

RP/0/RP0/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

RP/0/RP0/CPU0:CRS-8_P1(config-null0)#

Task ID

Task ID	Operations
interface	read, write

Examples

The following example shows how to enter null0 interface configuration mode:

RP/0/RP0/CPU0:router(config)# interface null 0

RP/0/RP0/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 arguments or keywords.

Defaults

No default behavior or values

Command Modes

EXEC

Command History

Release	Modification
Release 3.0	This command was first introduced on the Cisco CRS-1.
Release 3.2	This command was first supported on the Cisco XR 12000 Series Router.
Release 3.3.0	No modification.
Release 3.4.0	No modification.
Release 3.5.0	No modification.
Release 3.6.0	No modification.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes the proper task IDs. For detailed information about user groups and task IDs, see the Configuring AAA Services on Cisco IOS XR Software module of the Cisco IOS XR System Security Configuration Guide.

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/RP0/CPU0:router#show controllers null interface

Null interface:

name     : Null0

handle   : 0x00080010

rx_count : 0

tx_count : 0

drops    : 0

.

Table 69 describes the significant fields shown in the display.

Table 69 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	Displays statistics for all interfaces configured on the router.

show interfaces null0

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

show interfaces null0 [accounting [location {location description | 0/1/CPU0 | 0/2/0 | 0/2/1 | 0/2/CPU0 | 0/4/0 | 0/4/1 | 0/4/CPU0 | 0/5/CPU0} | rates [location {location description | 0/1/CPU0 | 0/2/0 | 0/2/1 | 0/2/CPU0 | 0/4/0 | 0/4/1 | 0/4/CPU0 | 0/5/CPU0} | | [begin line | exlude line | file file-name | include line | utility {cut | egrep | fgrep | head | less | sort | tail | uniq | wc | xargs}] | |] | brief | description | detail | location | summary | |

Syntax Descriptionshow

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 {location description | 0/1/CPU0 | 0/2/0 | 0/2/1 | 0/2/CPU0 | 0/4/0 | 0/4/1 | 0/4/CPU0 | 0/5/CPU0}	Specifies a fully qualified interface location.
summary	Shows interface in summary format.
|	Shows output modifiers for the interface.
begin line	Begins with the line that matches the regular expression line.
exclude line	Excludes lines that match.
file file-name	Saves the configuration to file.
include line	Includes lines that match.
utilility {cut | egrep | fgrep | head | less | sort | uniq | wc | xargs}	Includes a set of common UNIX utilities: •cut—Cuts out selected fields of each line of a file. •egrep—Extends regular expression grep. •fgrep—Configures fixed string expression grep. •head—Shows a set of lines/characters from the top of a file. •less— Enables fixed string pattern matching. •sort—Sorts, merges, or sequence-checks text files. •tail—Copies the last part of files. •uniq— Reports or filters out repeated lines in a file. •wc—Counts lines/words/characters of a file. •xargs—Constructs argument list(s) and invokes a program.
Word	Saves to file.
bootflash: destination file-name	Saves the configurationto bootflash: file system.
compactflash: destination file-name	Saves the configurationto compactflash: file system.
compactflasha: destination file-name	Saves the configurationto compactflasha: file system.
disk0: destination file-name	Saves the configurationto disk0: file system.
disk0a:	Saves the configurationto disk0a: file system.
disk1: destination file-name	Saves the configuration to disk1: file system.
disk1a: destination file-name	Saves the configuration to disk1a: file system.
ftp: address or name of remote host	Saves the configurationto ftp: file system.
harddisk: destination file-name	Saves the configurationto harddisk: file system.
harddiska: destination file-name	Saves the configurationto harddiska: file system.
harddiskb: destination file-name	Saves the configurationto harddiskb: file system.
nvram: destination file-name	Saves the configurationto NVRAM: file system.
rcp: destination file-name	Saves the configuration to rcp: file system.
tcp: destination file-name	Saves the configuration to tcp: file system.

Defaults

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 on the Cisco CRS-1 and Cisco XR 12000 Series Router.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes the proper task IDs. For detailed information about user groups and task IDs, see the Configuring AAA Services on Cisco IOS XR Software module of the Cisco IOS XR System Security Configuration Guide.

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/RP0/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