Juniper JUNOS OS 10.4 - FOR EX REV 1 Manual page 1015

Effects of Topology Changes on a Fast Failover Configuration
Copyright © 2010, Juniper Networks, Inc.
Chapter 37: EX4200 Virtual Chassis—Overview, Components, and Configurations
Figure 15: Traffic Redirected by Fast Failover After VCP Link Failures in a
Topology with Multiple Rings
In this scenario, the Virtual Chassis configuration has three rings: two rings that use
dedicated VCPs and one ring that uses SFP uplink module VCPs. Fast failover works
independently on each ring. Each dedicated VCP in a ring is backed up by another
dedicated VCP. Similarly, each SFP uplink module VCP is backed up by another SFP
uplink module VCP. Fast failover does not support a ring topology consisting of a mix of
dedicated VCPs and uplink module VCPs.
Once the fast failover feature has been activated, topology changes to the Virtual Chassis
configuration do not affect the fast failover configuration. In the event of a link or switch
failure, fast failover functions normally.
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