The following diagram shows the NSP ecosystem and provisioning of redundancy within a dual-site deployment.
Both local and remote redundancy are deployed. The remote redundancy, sometimes referred to as Disaster Recovery (DR) or geo redundancy, consists of a primary site and a secondary backup site each with an NSP VM cluster and a single VSR-NRC VM.
A heartbeat protocol runs between the NSP clusters in the primary site and the standby backup sites.
The VSR-NRC connects to both the NRC-P within its own site and to the NRC-P in the remote site. A failover to the remote VSR-NRC occurs when the primary site fails entirely, when the primary NRC-P fails, and when the VSR-NRC only fails.
TE-DB and LSP-DB full and partial synchronization among the cluster of two VSR-NRCs improves the coverage of remote redundancy. In addition, the VSR-NRC 1+1 redundancy scheme is extended to the remote site. The details of the VSR-NRC 1+1 dual site redundancy are provided in VSR-NRC dual-site redundancy.