Comparison Criteria

Use the Comparison Criteria page to manage the rules that define which lines or blocks of code to ignore when comparing configurations. Ignoring expected or inconsequential differences helps streamline the comparison process and reduce the noise.

Ignoring non-substantive differences, such as timestamps, empty lines, hostnames, or certificate blocks, makes it easier to focus on meaningful changes. It also prevents SolarWinds Observability SaaS from flagging expected differences when comparing a downloaded configuration to a baseline.

SolarWinds Observability SaaS uses regular expressions to identify content to ignore during comparisons.

Types of comparison criteria

Predefined criteria

Each organization has a default set of comparison criteria, previously used as an ignore baseline in Configuration Management.

• You can enable or disable predefined criteria.

• Edit predefined criteria to fit your needs.

• Delete predefined criteria.

Custom comparison criteria

You can create your own comparison criteria using regular expressions.

The patterns must follow ECMAScript syntax. For syntax details, see Regular expression syntax cheat sheet.

See Regular expression examples for some regular expressions that are commonly used to exclude lines and blocks. Other resources, such as www.Regular-Expressions.info, are available online to help you learn more about regular expressions.

Create comparison criteria

Create a regular expression to identify what should be ignored when comparing configurations.

1. Click Settings > Configuration Management > Comparison Criteria, and then click Create Comparison Criteria.

2. Enter a descriptive name.

3. Choose the type of match:

   • To exclude a single line, select Match Lines and enter a regular expression that identifies the beginning of the line into the Regular Expression box.

   • To exclude a block of text:

     1. Select Match Blocks.

     2. Enter a regular expression that identifies the beginning of the block into Block Start.

     3. Enter a regular expression that identifies the end of the block into Block End.

        The search for the pattern that identifies the end of the block is "lazy." That means if the pattern occurs multiple times, only the first occurrence of the pattern is found.

4. Optionally, you can add more details about this criterion into Comments.

5. Test the criterion:

   1. Select a network device added as an NCM node.

   2. Select a configuration (Running or Startup).

      The configuration appears on the right. Ignored lines or blocks are highlighted.

6. Enable the criterion to apply it during comparisons.

7. Click Save to return to the Comparison Criteria page.

Regular expression examples

The following are examples of regular expression patterns you can use to exclude configuration lines or blocks from comparison.

!Command: show startup-config
!Time: Fri Sep 12 05:52:54 2025
!Startup config saved at: Mon Sep  8 13:14:41 2025
version 5.2(1)N1(1)

Enable/disable comparison criteria

To ensure that lines/blocks are ignored, the criterion must be enabled.

To temporarily include lines/blocks when comparing configurations, disable the criterion.

1. Click Settings > Configuration Management > Comparison Criteria.

2. To enable a criterion, click the vertical ellipsis next to it and click Enable.

3. To disable a criterion, click the vertical ellipsis next to it and click Disable.

Edit comparison criteria

To change the regular expression or its name, complete these steps:

1. Click Settings > Configuration Management > Comparison Criteria.

2. Click the vertical ellipsis for a criterion and click Edit. Update the criterion definition and save your changes.

Delete comparison criteria

If a criterion is no longer relevant, delete it.

1. Click Settings > Configuration Management > Comparison Criteria.

2. Click the vertical ellipsis for a criterion and click Delete. The criterion is removed and no longer affects comparisons.