Wednesday, November 10, 2021

Non-Stop Routing (NSR) 101

After Non-Stop Forwarding, Stateful Switchover and Graceful Restart, it’s time for the pinnacle of high-availability switching: Non-Stop Routing (NSR)1.

The PowerPoint-level description of this idea sounds fantastic:

  • A device runs two active copies of its control plane.
  • There is no cold/warm start of the backup control plane. The failover is almost instantaneous.
  • The state of all control plane protocols is continuously synchronized between the two control plane instances. If one of them fails, the other one continues running.
  • A failure of a control plane instance is thus invisible from the outside.

If this sounds an awful lot like VMware Fault Tolerance, you’re not too far off the mark.



source https://blog.ipspace.net/2021/11/non-stop-routing.html?utm_source=atom_feed

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