Hello Ravi, that link is for the new WLC with IOS-XE, not for 2504 WLC. To respond the original question, you can't use multiple radius servers at once with WLC 2504. As a workaround you could use one ACS as your only radius server. Then you configure this ACS with proxy radius, so ACS could ask NPS1 and NPS2. However I would recommend to change your NPS1 and NPS2 with two ACS in a distributed deployment. That way you have the same configuration for the two ACS.
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