Supported Platforms
Related Documentation
- ACX, EX, M, MX, PTX, SRX, T Series, QFabric System, QFX Series standalone switches
- hold-time
- EX Series
- graceful-switchover
- EX, M, PTX, QFX, T Series
- Example: Configuring IS-IS for GRES with Graceful Restart
- M, PTX, T Series
- Understanding Graceful Routing Engine Switchover in the Junos OS
- Requirements for Routers with a Backup Router Configuration
- Resetting Local Statistics
- M, MX, PTX, T Series
- Graceful Routing Engine Switchover System Requirements
- graceful-switchover
Configuring Graceful Routing Engine Switchover
This section contains the following topics:
Enabling Graceful Routing Engine Switchover
By default, graceful Routing Engine switchover (GRES) is disabled. To configure GRES, include the graceful-switchover statement at the [edit chassis redundancy] hierarchy level.
When you enable GRES, the command-line interface (CLI) indicates which Routing Engine you are using. For example:
To disable GRES, delete the graceful-switchover statement from the [edit chassis redundancy] hierarchy level.
Configuring Graceful Routing Engine Switchover with Graceful Restart
When using GRES with Graceful Restart, if adjacencies between the Routing Engine and the neighboring peer 'helper' routers time out, graceful restart protocol extensions are unable to notify the peer 'helper' routers about the impending restart. Graceful restart can then stop and cause interruptions in traffic.
To ensure that these adjacencies are kept, change the hold-time for IS-IS protocols from the default of 27 seconds to a value higher than 40 seconds.
Synchronizing the Routing Engine Configuration
 | Note: A newly inserted backup Routing Engine automatically synchronizes its configuration with the master Routing Engine configuration. When you configure GRES, you can bring the backup Routing Engine online after the master Routing Engine is already running. There is no requirement to start the two Routing Engines simultaneously. |
Verifying Graceful Routing Engine Switchover Operation
To verify whether GRES is enabled on the backup Routing Engine, issue the show system switchover command. When the output of the command indicates that the Graceful switchover field is set to , GRES is operational. The status of the kernel database and configuration database synchronization between Routing Engines is also provided. For example:
Graceful switchover: On Configuration database: Ready Kernel database: Ready Peer state: Steady state
| Note: You must issue the show system switchover command on the backup Routing Engine. This command is not supported on the master Routing Engine. |
For more information about the show system switchover command, see the CLI Explorer.
Related Documentation
- ACX, EX, M, MX, PTX, SRX, T Series, QFabric System, QFX Series standalone switches
- hold-time
- EX Series
- graceful-switchover
- EX, M, PTX, QFX, T Series
- Example: Configuring IS-IS for GRES with Graceful Restart
- M, PTX, T Series
- Understanding Graceful Routing Engine Switchover in the Junos OS
- Requirements for Routers with a Backup Router Configuration
- Resetting Local Statistics
- M, MX, PTX, T Series
- Graceful Routing Engine Switchover System Requirements
- graceful-switchover
Published: 2014-07-25
Supported Platforms
Related Documentation
- ACX, EX, M, MX, PTX, SRX, T Series, QFabric System, QFX Series standalone switches
- hold-time
- EX Series
- graceful-switchover
- EX, M, PTX, QFX, T Series
- Example: Configuring IS-IS for GRES with Graceful Restart
- M, PTX, T Series
- Understanding Graceful Routing Engine Switchover in the Junos OS
- Requirements for Routers with a Backup Router Configuration
- Resetting Local Statistics
- M, MX, PTX, T Series
- Graceful Routing Engine Switchover System Requirements
- graceful-switchover
