fault tolerance between Cisco

Hi Experts,

Does anyone have a solution on how to create a fault tolerance between two cisco wireless controllers. I have two in production and i want to make sure they can backup each other in case of an issue.

Thank you.
SR ZakNetwork Solutions Asked:
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Ken BooneNetwork ConsultantCommented:
So if you want them to back each other up, you can look at this doc.  This is an older doc but it explains the process.


Basically you configure the AP with a primary and secondary controller.  This way if it can't connect the primary it will attempt to connect to the secondary.  Now the key here is that if you have say 50 APs on each controller and you want them to handle the load if the other one dies, you need to make sure each controller is licensed for 100 APs.

Here is a much more recent document to look at as well on backup controllers:

Craig BeckCommented:
Ken's solution is spot on, however you could configure them in HA SSO mode too if you want a truly seamless redundant setup.
SR ZakNetwork Solutions Author Commented:
The configuration of primary and secondary controller is already completed and the licenses are uploaded on both the controllers. 50 license on each controller.

I am looking to implement the HA SSO mode. CAn you please assist.

The 2 controllers are very far from each other in different buildings but I do have a fiber running accross. I just need some documentation to read and understand it.

Thank you.
Craig BeckCommented:
True HA SSO is only available with software v7.4>.  You could do it with v7.3 but it was rubbish.

You need a physical cable between the RP port on each WLC (ideally) although you can do it over a L2 VLAN if geographically separate.  The redundancy-port interface must be on the same subnet on each WLC and this also means that your management interfaces must be on the same subnet as the redundancy-port.  Basically all L2 VLANs that you have on the Primary WLC will need to be available at the second location.

You need to ensure that you have the same version of code on each WLC, then:

1] Connect the RP ports together.  (In your case I would recommend using a dedicated fiber-pair and media converters).
2] Configure the redundancy-management interfaces on the same subnet as the management interfaces.
3] Configure the peer redundancy-management IP address (the other WLC's redundancy-management IP on each WLC).
4] Configure one WLC as the secondary unit using the redundancy unit secondary command.
5] Issue the config redundancy mode sso command at each WLC.

Check this document for reference...


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