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.