redundancy RPR+ mode

[sarahr202]

Hi everybody

I have a very silly question.

"My book says in RPR+ mode, the redundant supervisor is booted,allowing the supervisor and route engine to initialize.No layer 2 or layer 3 functions are started,however.When the active module fails,the standby module finishes initializing without reloading other switch modules."

If supervisor engine does not reload modules then how how does it communicates with them? 

Does it mean  the supervisor engines in RPR+ mode,  load modules but when active supervisor engine fails, it does not reload them.?

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By default ,the active supervisor synchronizes its startup-config nd config register.  We can also specify other information that should be synchronized using this command:

router(config) redundancy

router(config-red)main-cpu

router(config-r-mc)auto-sync{ startup-config| config-register| bootvar}

what is bootvar?

thanks and have a great weekend

[Ivan Shirshin · Accepted solution]

Hi,

Yes, you are right  - the benefit of RPR+ is that there is no need to reload the modules on failover.

In RPR+ active is booted along with modules and comunicates with them, building l2 and l2 tables. Standby boots too but does not have l2/l3 tables maintained - this functions are not started on standby.  At this time active is responsible for managing all switch/router functions.

In RPR+ the configuration that runs is synchronized between the  active and the standby supervisors. All synchronization activities  inherited from RPR are also performed. The synchronization is done  before the switchover, and the information synchronized to the standby  is used when the standby becomes active to minimize the downtime - thus the line cards do not reload upon  switchover.

However, no  link layer or control-plane information is synchronized between the  active and the standby supervisors. Interfaces can bounce after  switchover, and the hardware contents need to be reprogrammed. So the RPR+  switchover time is 30 or more seconds, dependent on the size and complexity of the configuration.

Kind Regards,
Ivan

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[Ivan Shirshin · Accepted solution]

Hi,

BOOTVAR is a boot variable is used to specifiy the IOS file used from flash.  If you want to change it to a specific IOS image, use a command  "boot system flash sup-bootdisk:".

http://www.cisco.com/en/US/docs/ios/12_1/configfun/command/reference/frd2005.html#wp1018233

http://www.cisco.com/en/US/docs/ios/12_1/configfun/command/reference/frd2005.html#wp1018233

You can see current boot settings using "show bootvar".

Kind Regards,
Ivan

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