Controller Based WLANs

Answer

Environment: Aruba os 6.4 and above

This is a new feature introduced only from 6.4 code version.
 
How it works.
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Load balancing of authentication servers ensures that the authentication load is split across multiple authentication servers, thus avoiding any one particular authentication server from being overloaded.
This prevents any one authentication server from having to handle the full load during heavy authentication periods.
Earlier, the controller used the first authentication server in the server group list. The remaining servers in that server group will be used in sequential order only when an authentication server is down.
The load balancing algorithm computes the expected time taken to authenticate a new client for each authentication server and chooses that authentication server for which the expected authentication time is least.
The load balancing algorithm maintains re-authentication stickiness i.e. at the time of re-authentication the request will be forwarded to the same server where it was authenticated earlier.
 
 
How to Enable the Load balancing from CLI/WEBUI
========================================
(kuv_sek_7210_master) # show aaa authentication-server radius.
 
RADIUS Server List
------------------
Name       References Profile Status
----       ----------  --------------
KT_CPPM_1  5
KT_CPPM_2  4
win_rad    0
 
Total:3
 
 
(kuv_sek_7210_master) # show aaa server-group Guest25
 
Fail Through:No
Load Balance:No
 
Auth Servers
------------
Name       Server-Type  trim-FQDN  Match-Type  Match-Op  Match-Str
----       -----------  ---------  ----------  --------  ---------
KT_CPPM_1  Radius       No
KT_CPPM_2  Radius       No
 
Role/VLAN derivation rules
---------------------------
Priority  Attribute  Operation  Operand  Type  Action  Value  Validated
--------  ---------  ---------  -------  ----  ------  -----  ---------
 
(kuv_sek_7210_master) #configure terminal
(kuv_sek_7210_master) (config) # aaa server-group Guest25
(kuv_sek_7210_master) (Server Group "Guest25") #load-balance
 (kuv_sek_7210_master) # show aaa server-group Guest25
 
Fail Through:No
Load Balance:Yes
 
Auth Servers
------------
Name       Server-Type  trim-FQDN  Match-Type  Match-Op  Match-Str
----       -----------  ---------  ----------  --------  ---------
KT_CPPM_1  Radius       No
KT_CPPM_2  Radius       No
 
Role/VLAN derivation rules
---------------------------
Priority  Attribute  Operation  Operand  Type  Action  Value  ValidatedYou can use the following command to disable load balancing:
aaa server-group<sg_name>
no load-balance
 
Use the following command to disable it.
===============================
(kuv_sek_7210_master) (config) # aaa server-group Guest25
(kuv_sek_7210_master) (Server Group "Guest25") #no load-balance
 
NOTE:
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If you configure internal server in the server group, load balancing is not applicable to the internal server. Internal
Server will be used as fall back when all the other servers in the server group are down.

From Webui
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