Networking vendors love promoting novel overly complex technologies instead of solving their customers’ challenges with good network design. High-availability switching (the ability to continue packet forwarding during a control plane failure) is no exception.

Mechanisms

• Non-Stop Forwarding (NSF)
• Stateful Switchover (SSO)
• Graceful Restart (GR)
• Non-Stop Routing (NSR)

Interaction With Other Control-Plane Protocols

• Graceful Restart and Other Control Plane Protocols
• Graceful Restart and Routing Protocol Convergence
• Graceful Restart and BFD

Other Considerations

• Should We Use Redundant Supervisors?
• So You Need ISSU on Your ToR switch? Really?
• Interactions Between BFD and Graceful Restart
• Big Picture: BFD, Non-Stop Forwarding, and Graceful Restart