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Concerning the Redundant Routers for VPCs, the main goal behind its implementation was to increase a critical applicationsapplication's uptime, by offering a better Disaster Recovery strategy by quickly switching network traffic to a backup virtual router, hence increasing business continuity. 

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Thanks to the redundant nature of a CloudStack VPC, your applications are by default high available. The VPC will contain tow two virtual routers, where the configuration of tiers, ACLs, public IPs, Load Balancers and Port Forwarding are persisted. In case one of the routers crash or loses networking connection, the traffic will be automatically forwarded to the backup router, which in that case will have its status changed to master.

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