Router Processor Redundancy (RPR)
Redundant Supervisor Engines – Handy having two brains!
When implemented back in the day in IOS 12.1(13)F it was a great technology. Over time NSR and SSO have addressed the shortcomings with better failover times. RPR on the 6500 series is around 2-4 minutes and on the 4500 series less than 60 seconds. RPR+ only available on the 6500 series comes in at around 30-60 seconds. In this day and age that is a noticeable downtime and isn’t transparent to the end user.
Supervisor engine that forwards all the L2/L3 traffic is the active supervisor engine. The other supervisor engine waits in standby. Both supervisor engines talk to each other.
| Trigger | Event |
| Routing/Switching processor crash | Switching modules power cycled |
| Manual | Subsystems on standby are activated |
| Removal | ACLs reprogrammed into Supervisor engine. |
RPR+
Improved switch over times and Reduced to around 30-60 seconds with no reloading of modules required.
Easy configuration makes RPR (when it was used) too good to not configure!
sw(config)# redundancy sw(config-red)# mode rpr-plus
Simple as that.
Verify with the following
sw# show redundancy states