Switch Redundancy Modes (RPR, RPR+, SSO)

[danielseijas3010]

HI Everyone, 

I am currently studying for CCNP Switching 300-115 and there is a topic I can't fully understand. Please let me know if anything mentioned below is correct:

1.- Catalyst 4500R, 6500 and 6800 can accept two supervisor modules installed in a single chassis

2.- The Redundancy Modes in the title above dictate how the active and standby supervisor module will synchronize information like Routing Updates and Configurations in the SAME CHASSIS. This being said, these modes are for redundancy within the same physical switch AND NOT within two or more switches configured as logical switches? Please let me know if this is correct

3.- To configure redundancy, the book says that you have to apply the commands on BOTH supervisors as they are not yet synchronizing everything. However, it does not mention what command or HOW we switch among supervisors when we are in front of the CLI. Can you shed some light on this???

Thanks in Advance

Daniel Seijas

CCNA

[InayathUlla Sharieff]

Hi Daniel,

1.- Catalyst 4500R, 6500 and 6800 can accept two supervisor modules installed in a single chassis

Answer:- Yes thats true. Each chasis can have max of 2 Supervisor modules . There are different types of Supervisor modules.
6800 can only accept Sup-2T.

2.- The Redundancy Modes in the title above dictate how the active and standby supervisor module will synchronize information like Routing Updates and Configurations in the SAME CHASSIS. This being said, these modes are for redundancy within the same physical switch AND NOT within two or more switches configured as logical switches? Please let me know if this is correct

Answer:- Yes.

3.- To configure redundancy, the book says that you have to apply the commands on BOTH supervisors as they are not yet synchronizing everything. However, it does not mention what command or HOW we switch among supervisors when we are in front of the CLI. Can you shed some light on this???

Answer: In software, supervisor engine redundancy is enabled by running the redundant supervisor engine in route processor redundancy (RPR) or stateful switchover (SSO) operating mode.

Commands:-
Switch> enable 
 Switch# configure terminal 
 Enter configuration commands, one per line. End with CNTL/Z.
 Switch(config)# redundancy 
 Switch(config-red)# mode sso  or rpr
 Switch(config-red)# end 

show redundancy >>>>>> check here for mode you have configured.

b-

This example shows how to reenable the default automatic synchronization feature using the auto-sync standard command to synchronize the startup-config and config-register configuration of the active supervisor engine with the redundant supervisor engine. Updates for the boot variables are automatic and cannot be disabled.
 Switch(config)# redundancy
 Switch(config-red)# main-cpu
 Switch(config-r-mc)# auto-sync standard
 Switch(config-r-mc)# end
 Switch# copy running-config startup-config

c-

If you want to do the Sup failover(From Active to standby and standby to take over the active role):-

Switch# redundancy force-switchover

HTH
Regards
Inayath
*********Please do not forget to rate the post if helpfull**

[danielseijas3010]

Thanks!, however I am still confused with question #3. In order to RPR+ or any other mode to work, we need to apply the commands above on both supervisors. Before I can even think about failover, I need the commands to be applied on both supervisors so I assume the following command won't work when this configuration is being applied the first time:
 

Switch# redundancy force-switchover

So, what commands would you apply to enable RPR+ redundancy mode on an out-of-the-box 6500 chassis that has two supervisors installed?

[InayathUlla Sharieff]

Hi Daniel,

Here is the thing:-

As you know when you have two supervisor modules installed one will be active and other wil be standby. There is no way you can configure anything on the standby when one of the sup is active.(Only one control plane will  be active at any given point of time).

So what ever you have configured on the Active will get synchronized automatically to the standby sup module when it gets detected.

{

PR+ Supervisor Engine Configuration Synchronization

With RPR+ mode, the following operations trigger configuration synchronization:

• When a redundant supervisor engine first comes online, the startup-config file is copied from the active supervisor engine to the redundant supervisor engine. This synchronization overwrites any existing startup configuration file on the redundant supervisor engine.
• When configuration changes occur during normal operation, redundancy performs an incremental synchronization from the active supervisor engine to the redundant supervisor engine. Redundancy synchronizes user-entered CLI commands incrementally line-by-line from the active supervisor engine to the redundant supervisor engine.
• }

HTH

Regards

Inayath

***please do not forget to rate all usefull posts***

[kakatiya]

Dont VSS setup on say for example 6509 -E series chasis with sup 720 -10GE supervisor support SSO mode between two multiple chasis operating as one ?