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IS-IS User Guide
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Example: Enabling Wide IS-IS Metrics for Traffic Engineering

date_range 24-Nov-23

This example shows how to allow a wide range of metric values on IS-IS interfaces.

Requirements

Before you begin, configure IS-IS on both routers. See Example: Configuring IS-IS for information about the sample IS-IS configuration.

Overview

Figure 1 shows the topology used in this example.

Figure 1: IS-IS Wide Metrics TopologyIS-IS Wide Metrics Topology

This example describes the steps on Device R1.

Configuration

Procedure

CLI Quick Configuration

To quickly configure this example, copy the following commands, paste them into a text file, remove any line breaks, change any details necessary to match your network configuration, and then copy and paste the commands into the CLI at the [edit] hierarchy level.

Device R1

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set protocols isis level 2 wide-metrics-only
set protocols isis level 1 wide-metrics-only
set protocols isis interface lt-1/2/0.1 level 2 metric 100
set protocols isis interface lt-1/2/0.1 level 1 metric 100

Step-by-Step Procedure

The following example requires you to navigate various levels in the configuration hierarchy. For information about navigating the CLI, see Using the CLI Editor in Configuration Mode in the CLI User Guide.

To configure IS-IS checksums:

  1. Configure a metric of 100 on the interface at both IS-IS levels.

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    [edit protocols isis interface lt-1/2/0.1]
    user@R1# set level 2 metric 100
    user@R1# set level 1 metric 100
    
  2. Enable wide metrics.

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    [edit protocols isis]
    user@R1# set level 2 wide-metrics-only
    user@R1# set level 1 wide-metrics-only
    

Results

From configuration mode, confirm your configuration by entering the show protocols command. If the output does not display the intended configuration, repeat the instructions in this example to correct the configuration.

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user@R1# show protocols
isis {
    level 2 wide-metrics-only;
    level 1 wide-metrics-only;
    interface lt-1/2/0.1 {
        level 2 metric 100;
        level 1 metric 100;
    }
}

If you are done configuring the device, enter commit from configuration mode.

Verification

Confirm that the configuration is working properly.

Verifying That Wide Metrics Are Enabled

Purpose

Make sure that the interface has the expected metric.

Action

From operational mode, enter the show isis interface extensive command.

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user@R1> show isis interface lt-1/2/0.1 extensive
IS-IS interface database:
lt-1/2/0.1
  Index: 68, State: 0x6, Circuit id: 0x1, Circuit type: 3
  LSP interval: 100 ms, CSNP interval: 10 s, Loose Hello padding
  Adjacency advertisement: Advertise
  Level 1
    Adjacencies: 1, Priority: 64, Metric: 100
    Hello Interval: 9.000 s, Hold Time: 27 s
    Designated Router: tp5-R2.02 (not us)
  Level 2
    Adjacencies: 1, Priority: 64, Metric: 100
    Hello Interval: 9.000 s, Hold Time: 27 s
    Designated Router: tp5-R2.02 (not us)

Meaning

The output shows that the metric is set to 100, as expected, at both Level 1 and Level 2.

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