Understanding Split And Merge In An Ex4200 Virtual Chassis - Juniper JUNOS OS 10.4 - FOR EX REV 1 Manual

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Understanding Split and Merge in an EX4200 Virtual Chassis

What Happens When an EX4200 Virtual Chassis Configuration Splits
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OS for EX Series Ethernet Switches, Release 10.4
Understanding EX4200 Virtual Chassis Configuration on page 904
Example: Configuring Fast Failover on Uplink Module VCPs to Reroute Traffic When
an EX4200 Virtual Chassis Switch or Intermember Link Fails on page 963
Setting an EX4200 Switch Uplink Module Port as a Virtual Chassis Port (CLI Procedure)
on page 994
In an EX4200 Virtual Chassis configuration, two or more Juniper Networks EX4200
Ethernet Switches are connected together to form a unit that is managed as a single
chassis. If there is a disruption to the Virtual Chassis configuration due to member switches
failing or being removed from the configuration, the Virtual Chassis configuration splits
into two separate Virtual Chassis. This situation could cause disruptions in the network
if the two separate configurations share common resources, such as global IP addresses.
The split and merge feature provides a method to prevent the separate Virtual Chassis
configurations from adversely affecting the network and also allows the two parts to
merge back into a single Virtual Chassis configuration.
NOTE: If a Virtual Chassis configuration splits into separate parts, we
recommend that you resolve the problem that caused the Virtual Chassis
configuration to split as soon as possible.
You can also use this feature to merge two active but separate Virtual Chassis that have
not previously been part of the same configuration into one Virtual Chassis configuration.
NOTE: The split and merge feature is enabled by default on EX4200 switches.
You can disable the split and merge feature by using the
no-split-detection
This topic describes:
What Happens When an EX4200 Virtual Chassis Configuration Splits on page 912
Merging EX4200 Virtual Chassis Configurations on page 913
When an EX4200 Virtual Chassis configuration splits into two separate Virtual Chassis
configurations, the individual member switches detect this topology change and run the
master election algorithm to select a new master for each of the two Virtual Chassis
configurations. The new masters then determine whether their Virtual Chassis
configuration remains active. One of the configurations remains active based on the
following:
It contains both the stable master and the stable backup (that is, the master and
backup from the original Virtual Chassis configuration before the split).
command.
Copyright © 2010, Juniper Networks, Inc.
set virtual-chassis