Methods and systems are provided for provisioning and managing network-based virtual private networks (VPNs). According to one embodiment, virtual routers (VRs) distributed among service processing switches are provisioned by a service management system (SMS) to support network-based customer virtual private networks (VPNs) by generating a routing configuration based on (i) site reachability information for the service processing switches and (ii) a global customer routing profile for at least one customer. A custom routing profile is received by the SMS from a customer network management system (CNMS), the custom routing profile identifies one or more routing protocols to be used for one or more segments of a network-based customer VPN. The network-based customer VPN is reconfigured by the SMS generating appropriate routing configurations for VRs partitioned to the customer based on a subset of the site reachability information associated with sites of the customer and the custom routing profile.