 | Copyright © 2008, Juniper Networks, Inc. All rights reserved. Trademark Notice. | |
You must configure IS-IS graceful restart on the router and on all IS-IS neighbors before you begin the in-service software upgrade. When the unified ISSU process verifies the upgrade requirements during the initialization phase, it detects whether graceful restart is configured. If it is not configured, the CLI displays a warning message and prompts you to proceed or halt. You can stop at this point to configure graceful restart.
If instead you proceed, the in-service software upgrade can complete successfully, but the IS-IS neighbors are likely to break the adjacencies with the upgrading router and consider that routes formerly reached through this router are now unreachable. When the in-service software upgrade completes and the routing protocols restart, the IS-IS neighbors can relearn the routes through the router.
When you issue the issu start command, IS-IS lengthens its hello timer values and sends LSPs with the new values. The upgrade proceeds when the IS-IS neighbors have acknowledged the new values.
| Copyright © 2008, Juniper Networks, Inc. All rights reserved. Trademark Notice. | |