Junos® OS for EX Series Ethernet Switches ... - Juniper Networks

Chapter 3: Configuring EX4200 and EX4500 Virtual ChassisConfiguring Graceful Routing Engine Switchover in an EX4200 or EX4500 VirtualChassis (CLI Procedure)In an EX4200 Virtual Chassis, EX4500 Virtual Chassis, or mixed EX4200 and EX4500Virtual Chassis, one member switch is assigned the master role and has the masterRouing Engine. Another member switch is assigned the backup role and has the backupRouting Engine. Graceful Routing Engine switchover (GRES) enables the master andbackup Routing Engines in a Virtual Chassis configuration to switch from the master tobackup without interruption to packet forwarding. When you configure graceful RoutingEngine switchover, the backup Routing Engine automatically synchronizes with the masterRouting Engine to preserve kernel state information and the forwarding state.To set up the Virtual Chassis configuration to use graceful Routing Engine switchover(GRES):1. Set up a minimum of two switches in a Virtual Chassis configuration with mastershippriority of 255:[edit]user@switch# set virtual-chassis member 0 mastership-priority 255[edit]user@switch# set virtual-chassis member 1 mastership-priority 2552. Set up graceful Routing Engine switchover:[edit]user@switch# set chassis redundancy graceful-switchoverCommit the configuration.RelatedDocumentation• Example: Configuring an EX4200 Virtual Chassis with a Master and Backup in a SingleWiring Closet on page 32• High Availability Features for EX Series Switches Overview• Understanding EX3300, EX4200, and EX4500 Virtual Chassis Configuration on page 16Copyright © 2011, Juniper Networks, Inc.155