Contextual Configuration Diff Utility

The Contextual Configuration Diff Utility feature provides the ability to perform a line-by-line comparison of any two configuration files (accessible through the Cisco IOS XE Integrated File System [IFS]) and generate a list of the differences between them. The generated output includes information regarding configuration lines that have been added, modified, or deleted, and the configuration modes within which a changed configuration line exists.

Prerequisites for Contextual Configuration Diff Utility

The format of the configuration files used for the Contextual Configuration Diff Utility feature must comply with standard Cisco IOS XE configuration file indentation rules as follows:

  • Start all commands on a new line with no indentation, unless the command is within a configuration submode.

  • Indent commands within a first-level configuration submode one space.

  • Indent commands within a second-level configuration submode two spaces.

  • Indent commands within subsequent submodes accordingly.

The router must have a contiguous block of memory larger than the combined size of the two configuration files being compared.

Restrictions for Contextual Configuration Diff Utility

If the device does not have a contiguous block of memory larger than the combined size of the two configuration files being compared, the diff operation fails.

Information About Contextual Configuration Diff Utility

Benefits of the Contextual Configuration Diff Utility

The Contextual Configuration Diff Utility feature provides the ability to perform a line-by-line comparison of any two configuration files (accessible through the Cisco IOS XE File System [IFS]) and generate a list of the differences between them. The generated output includes information regarding the following items:

  • Configuration lines that have been added, modified, or deleted.

  • Configuration modes within which a changed configuration line exists.

  • Location changes of configuration lines that are order-sensitive. For example, the ip access-list and community-lists commands are order-sensitive commands dependent on where they are listed within a configuration file in relation to other Cisco IOS XE commands of similar type.

Contextual Configuration Diff Utility Output Format

Diff Operation

The Contextual Configuration Diff Utility feature uses the filenames of two configuration files as input. A diff operation is performed on the specified files and a list of differences between the two files is generated as output by using the show archive config differences command. Interpreting the output is dependent on the order in which the two files are specified in the command. In this section, we assume that the filename of the file entered first is file1 and the filename of the file entered second is file2. Each entry in the generated output list is prefixed with a unique text symbol to indicate the type of difference found. The text symbols and their meanings are as follows:

  • A minus symbol (–) indicates that the configuration line exists in file1 but not in file2.

  • A plus symbol (+) indicates that the configuration line exists in file2 but not in file1.

  • An exclamation point (!) with descriptive comments identifies order-sensitive configuration lines whose location is different in file1 than in file2.

Incremental Diff Operation

Some applications require that the generated output of a diff operation contain configuration lines that are unmodified (in other words, without the minus and plus symbols). For these applications, an incremental diff operation can be performed by using the show archive config incremental-diffs command, which compares a specified configuration file to the running configuration file ().

When an incremental diff operation is performed, a list of the configuration lines that do not appear in the running configuration file (in other words, configuration lines that appear only in the specified file that is being compared to the running configuration file) is generated as output. An exclamation point (!) with descriptive comments identifies order-sensitive configuration lines whose location is different in the specified configuration file than in the running configuration file.

How to Use the Contextual Configuration Diff Utility

Performing a Line-by-Line File Comparison Using the Contextual Configuration Diff Utility

SUMMARY STEPS

  1. enable
  2. Enter one of the following:
    • show archive config differences [file1 [file2]]
    • show archive config incremental-diffs file
  3. exit

DETAILED STEPS

  Command or Action Purpose

Step 1

enable

Example:


Device> enable

Enables privileged EXEC mode.

  • Enter your password if prompted.

Step 2

Enter one of the following:

  • show archive config differences [file1 [file2]]
  • show archive config incremental-diffs file

Example:


Device# show archive config differences running-config startup-config

Example:


Device# show archive config incremental-diffs nvram:startup-config

Performs a line-by-line comparison of any two configuration files (accessible through the Cisco IOS File System and generates a list of the differences between them.

or

Performs a line-by-line comparison of a specified configuration file to the running configuration file and generates a list of the configuration lines that do not appear in the running configuration file.

Step 3

exit

Example:


Device# exit

Exits to user EXEC mode.

Configuration Examples for the Contextual Configuration Diff Utility

Diff Operation Example

In this example, a diff operation is performed on the running and startup configuration files. The table below shows the configuration files used for this example.

Table 1. Configuration Files Used for the Diff Operation Example

Running Configuration File

Startup Configuration File 


no ip subnet-zero

ip cef

interface FastEthernet1/0

 ip address 10.7.7.7 255.0.0.0

 no ip route-cache

 no ip mroute-cache

 duplex half

no ip classless

snmp-server community public RO
 

ip subnet-zero

ip cef

ip name-server 10.4.4.4

voice dnis-map 1

 dnis 111

interface FastEthernet1/0

 no ip address

 no ip route-cache

 no ip mroute-cache

 shutdown

 duplex half

ip default-gateway 10.5.5.5

ip classless

access-list 110 deny   ip any host 10.1.1.1

access-list 110 deny   ip any host 10.1.1.2

access-list 110 deny   ip any host 10.1.1.3

snmp-server community private RW

The following is sample output from the show archive config differences command. This sample output displays the results of the diff operation performed on the configuration files in the table below. 


Device# show archive config differences system:running-config nvram:startup-config


+ip subnet-zero

+ip name-server 10.4.4.4

+voice dnis-map 1 

 +dnis 111

interface FastEthernet1/0

 +no ip address

 +shutdown

+ip default-gateway 10.5.5.5

+ip classless

+access-list 110 deny ip any host 10.1.1.1

+access-list 110 deny ip any host 10.1.1.2

+access-list 110 deny ip any host 10.1.1.3

+snmp-server community private RW

-no ip subnet-zero

interface FastEthernet1/0

 -ip address 10.7.7.7 255.0.0.0

-no ip classless

-snmp-server community public RO

Incremental Diff Operation Example

In this example, an incremental diff operation is performed on the startup and running configuration files. The table below shows the configuration files used for this example.

Table 2. Configuration Files Used for the Incremental Diff Operation Example

Startup Configuration File

Running Configuration File 


ip subnet-zero

ip cef

ip name-server 10.4.4.4

voice dnis-map 1

 dnis 111

interface FastEthernet1/0

 no ip address

 no ip route-cache

 no ip mroute-cache

 shutdown

 duplex half

ip default-gateway 10.5.5.5

ip classless

access-list 110 deny   ip any host 10.1.1.1

access-list 110 deny   ip any host 10.1.1.2

access-list 110 deny   ip any host 10.1.1.3

snmp-server community private RW
 

no ip subnet-zero

ip cef

interface FastEthernet1/0

 ip address 10.7.7.7 255.0.0.0

 no ip route-cache

 no ip mroute-cache

 duplex half

no ip classless

snmp-server community public RO

The following is sample output from the show archive config incremental-diffs command. This sample output displays the results of the incremental diff operation performed on the configuration files in the table below. 


Device# show archive config incremental-diffs startup-config


ip subnet-zero

ip name-server 10.4.4.4

voice dnis-map 1 

 dnis 111

interface FastEthernet1/0

 no ip address

 shutdown

ip default-gateway 10.5.5.5

ip classless

 access-list 110 deny   ip any host 10.1.1.1

 access-list 110 deny   ip any host 10.1.1.2

 access-list 110 deny   ip any host 10.1.1.3

snmp-server community private RW

Additional References

The following sections provide references related to the Configuration Partitioning feature.

Related Documents

Related Topic

Document Title

Running configuration performance enhancement--parserconfigcache for interfaces.

Configuration Generation Performance Enhancement

Provisioning of customer services, Config Rollback, Config Locking, and configuration access control

Contextual Configuration Diff Utility

Configuration management--Config change logging.

Configuration Change Notification and Logging

Configuration management --Quick-save for config change logging1.

Configuration Logger Persistency

Cisco IOS software configuration access control and config session locking (“Config Lock”).

Exclusive Configuration Change Access and Access Session Locking

1 The “Configuration Logger Persistency” feature allows saving just the commands entered since the last startup-config file was generated, rather than saving the entire startup configuration.

Standards

Standard

Title

No standards are associated with this feature.

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MIBs

MIB

MIBs Link

No new or modified MIBs are supported by this feature, and support for existing MIBs has not been modified by this feature.

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RFCs

RFC

Title

No new or modified RFCs are supported by this feature, and support for existing RFCs has not been modified by this feature.

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Technical Assistance

Description

Link

The Cisco Support website provides extensive online resources, including documentation and tools for troubleshooting and resolving technical issues with Cisco products and technologies.

To receive security and technical information about your products, you can subscribe to various services, such as the Product Alert Tool (accessed from Field Notices), the Cisco Technical Services Newsletter, and Really Simple Syndication (RSS) Feeds.

Access to most tools on the Cisco Support website requires a Cisco.com user ID and password..

http://www.cisco.com/techsupport

Feature Information for Contextual Configuration Diff Utility

The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required.
Table 3. Feature Information for Contextual Configuration Diff Utility

Feature Name

Releases

Feature Information

Contextual Configuration Diff Utility

Cisco IOS XE Release 2.1

The Contextual Configuration Diff Utility feature provides the ability to perform a line-by-line comparison of any two configuration files and generate a list of the differences between them. The generated output includes information regarding configuration lines that have been added, modified, or deleted, and the configuration modes within which a changed configuration line exists.

In Cisco IOS XE Release 2.1, this feature was introduced on Cisco ASR 1000 Series Routers.

The following commands were modified by this feature: show archive config differences , show archive config incremental-diffs .