Example: Configuring IS-IS

This example shows how to configure IS-IS.

• Requirements
• Overview
• Configuration
• Verification

Requirements

Before you begin:

1. Configure network interfaces. See the Junos OS Interfaces Configuration Guide for Security Devices.
2. Configure security filters. See the Junos OS Security Configuration Guide.

Overview

In this example, you configure the 49.0001.00a0.c96b.c490.00 NET address on the lo0 interface. Additionally, you configure the ISO family on the ge-0/0/1 physical interface.

Configuration

CLI Quick Configuration

To quickly configure IS-IS, copy the following commands and paste them into the CLI:

Step-by-Step Procedure

The following example requires you to navigate various levels in the configuration hierarchy. For instructions on how to do that, see Using the CLI Editor in Configuration Mode.

To configure IS-IS:

1. Enable IS-IS if your router is in secure context.
   [edit]user@host# set security forwarding-options family iso mode packet-based

   Note: Additionally, you must configure the ISO family on all interfaces that are supporting the IS-IS protocol.

2. Create an interface.
   [edit]user@host# edit interfaces
3. Configure the loopback interface.
   [edit interfaces]user@host# edit lo0
4. Configure the logical unit.
   [edit interfaces lo0]user@host# edit unit 0
5. Set the NET address.
   [edit interfaces lo0 unit 0]user@host# set family iso address 49.0001.00a0.c96b.c490.00
6. Configure a physical interface.
   [edit]user@host# edit interfaces ge-0/0/01 unit 0
7. Configure the interface.
   [edit interfaces ge-0/0/0 unit 0]user@host# set family iso address 49.0001.00a0.c96b.c490.00
8. Configure IS-IS.
   [edit]user@host# edit protocols
9. Set IS-IS.
   [edit protocols]user@host# set isis interface all

Results

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

For brevity, this show interfaces and show protocols command output includes only the configuration that is relevant to this example. Any other configuration on the system has been replaced with ellipses (...).

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

Verification

To confirm that the configuration is working properly, perform these tasks:

• Verifying IS-IS Interface Configuration
• Verifying IS-IS Interface Configuration Detail
• Verifying IS-IS Adjacencies
• Verifying IS-IS Adjacencies in Detail

Verifying IS-IS Interface Configuration

Purpose

Verify the status of the IS-IS-enabled interfaces.

Action

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

IS-IS interface database:
Interface  L CirID Level 1	DR	Level 2 DR
lo0.0      3  0x1  router1		router.01
ge-0/0/1.0 2  0x9  Disabled		router.03
ge-1/0/0.0 2	0x7  Disabled		router.05

Meaning

Verify that the output shows the intended configuration of the interfaces on which IS-IS is enabled.

Verifying IS-IS Interface Configuration Detail

Purpose

Verify the details of IS-IS-enabled interfaces.

Action

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

lo0.0
			Index:3, State:0x7, Circuit id: 0x1, Circuit type:3
			LSP interval: 100 ms, Sysid: router1
			Level Adjacencies Priority Metric Hello(s) Hold(s)
			    1           0       64      0       9    27
       2           0       64      0       9    27
		ge-0/0/1.0
       Index:3, State:0x106, Circuit id: 0x9, Circuit type:2
			LSP interval: 100 ms, Sysid: router1
			Level Adjacencies Priority Metric Hello(s) Hold(s)
			    1           0       64      0       9    27
       2           0       64      0       9    27

Meaning

Check the following output fields and verify that the output shows the intended configuration of IS-IS-enabled interfaces:

• Interface—Interface configured for IS-IS.
• State—Internal implementation information.
• Circuit id—Circuit identifier.
• Circuit type—Configured level of IS-IS:
  • 1—Level 1 only
  • 2—Level 2 only
  • 3—Level 1 and Level 2
• LSP interval—Time between IS-IS information messages.
• Sysid—System identifier.
• L or Level—Type of adjacency:
  • 1—Level 1 only
  • 2—Level 2 only
  • 3—Level 1 and Level 2
• Adjacencies—Adjacencies established on the interface.
• Priority—Priority value established on the interface.
• Metric—Metric value for the interface.
• Hello(s)—Intervals between hello PDUs.
• Hold(s)—Hold time on the interface.

Verifying IS-IS Adjacencies

Purpose

Display brief information about IS-IS neighbors.

Action

From operational mode, enter the show isis adjacency brief command.

IS-IS adjacency database:
		 Interface		System				L  State				Hold (secs) SNPA
		 ge-0/0/0.0		1921.6800.5067		2  Up								13
		 ge-0/0/1.0		1921.6800.5067		2	Up								25
		 ge-0/0/2.0		1921.6800.5067		2  Up								19

Meaning

Verify the adjacent routers in the IS-IS database.

Verifying IS-IS Adjacencies in Detail

Purpose

Display extensive information about IS-IS neighbors.

Action

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

R1
  Interface: so-0/0/0.0, Level: 2, State: Up, Expires in 25 secs
  Priority: 0, Up/Down transitions: 1, Last transition: 4w6d 19:38:52 ago
  Circuit type: 2, Speaks: IP, IPv6
  Topologies: Unicast
  Restart capable: Yes
  IP addresses: 10.1.12.1
  Transition log:
  When                  State        Reason
  Wed Jul 13 16:26:11   Up           Seenself

R3
  Interface: so-0/0/1.0, Level: 2, State: Up, Expires in 23 secs
  Priority: 0, Up/Down transitions: 1, Last transition: 6w5d 19:07:16 ago
  Circuit type: 2, Speaks: IP, IPv6
  Topologies: Unicast
  Restart capable: Yes
  IP addresses: 10.1.23.2
  Transition log:
  When                  State        Reason
  Thu Jun 30 16:57:46   Up           Seenself

R6
  Interface: so-0/0/2.0, Level: 2, State: Up, Expires in 25 secs
  Priority: 0, Up/Down transitions: 1, Last transition: 6w0d 18:01:18 ago
  Circuit type: 2, Speaks: IP, IPv6
  Topologies: Unicast
  Restart capable: Yes
  IP addresses: 10.1.26.2
  Transition log:
  When                  State        Reason
  Tue Jul  5 18:03:45   Up           Seenself 

Meaning

Check the following fields and verify the adjacency information about IS-IS neighbors:

• Interface—Interface through which the neighbor is reachable.
• L or Level—Configured level of IS-IS:
  • 1—Level 1 only
  • 2—Level 2 only
  • 3—Level 1 and Level 2

  An exclamation point before the level number indicates that the adjacency is missing an IP address.

• State—Status of the adjacency: Up, Down, New, One-way, Initializing, or Rejected.
• Event—Message that identifies the cause of a state.
• Down reason—Reason the adjacency is down.
• Restart capable—A neighbor is configured for graceful restart.
• Transition log—List of transitions including When, State, and Reason.

Related Topics

• Junos OS Feature Support Reference for SRX Series and J Series Devices

• Configuring IS-IS Designated Routers (CLI Procedure)

• show isis interface in the Junos Routing Protocols and Policies Command Reference

• show isis adjacency in the Junos Routing Protocols and Policies Command Reference