In a network routing system,a control blade provides for redundancy and
failover of virtual routers (VRs) instantiated by objects running on
processing engines of the several virtual routing engines (VREs). When
the control blade detects a failure of one processing engines, it may
identify the virtual private networks (VPNs) and/or VRs operating on the
failed processing engine. The control blade identifies a set of command
lines corresponding with the identified VPNs and VRs, and replays the set
of command lines with an identity of a new processing engine to recreate
the identified VPNs and VRs on the new processing engine.