A network engineer needs to configure a high availability feature for a data center that uses a Cisco Nexus 7700 Series Switch that is configured…

Non-Stop Routing (NSR) is a high-availability feature designed for systems with dual supervisors, like the Cisco Nexus 7700. NSR synchronizes routing protocol state information between the active and standby supervisors. During a supervisor switchover, the standby seamlessly takes over without resetting neighbor adjacencies. This meets all requirements: it ensures resilience, prevents routing flaps (reducing instability), does not require neighbors to be notified of a restart (as sessions are maintained), and allows continuous traffic forwarding (Non-Stop Forwarding is inherent). Graceful Restart (GR) depends on neighbor cooperation, whereas NSR is self-contained within the device.

A. Graceful restart requires neighbor routers to support the GR capability, making it an externally dependent solution, unlike the self-contained NSR.
B. NSF (Non-Stop Forwarding) is a component that separates the control and data planes but relies on a mechanism like GR or NSR to rebuild control plane state.
D. BFD is a fast failure detection protocol. It can trigger an HA event like a switchover but is not the mechanism that provides the stateful failover itself.

1. Cisco, "Cisco Nexus 7000 Series NX-OS High Availability and Redundancy Guide," Chapter: "Configuring Redundancy". This guide explicitly states, "Nonstop routing (NSR) allows the device to perform a stateful switchover (SSO) of the active supervisor module to the standby supervisor module without the assistance of the neighboring devices." This directly aligns with the question's requirements.

2. Cisco, "Cisco Nexus 7000 Series NX-OS Unicast Routing Configuration Guide, Release 8.x," Chapter: "Implementing BGP". The chapter on BGP discusses both Graceful Restart and NSR, highlighting that NSR provides a more resilient solution for dual-supervisor platforms by maintaining state and not relying on peers.