Two SSID's for same VLAN - problems?

  • I want to test 802.1x on a test SSID. Wasn't sure if making a test SSID associated to a VLAN that already has another SSID associated with it would cause a problem with the customer facing SSID.

    Ex. SSID 1 = VLAN 1 SSID 2 = VLAN 1 - has 802.1x specific configurations

    what vendors and firmware versions are you trying it on? what are you using for auth server?

    Vendors - Cisco 1142 AP's (autonomous) - for authentication - plan to use a Windows DC, running IAS!

    What value does the 802.1X test have with the *same* SSID?

  • Cisco won't allow more than one SSID per VLAN per Interface using Autonomous APs. Can't answer for WLCs, but I would assume the same thing.

    If you have a single radio AP, I recommend having a test VLAN to go with the test SSID and then have your router route between the VLANs.

    AP Message When Attempting:

    #conf t
    Enter configuration commands, one per line.  End with CNTL/Z.
    (config)#dot11 ssid Example
    (config-ssid)#vlan 21
    Warning: Vlan 21 already mapped to SSID Guest. SSIDs with same vlan association cannot be attached to the same interface.
    
    (config-ssid)#
    

    Originally I took this as one to one but when I tried it on a dual radio AP I was able to replace the Guest SSID on the 5Ghz radio:

    (config-ssid)#int D1
    (config-if)#no ssid Guest
    (config-if)#ssid Example
    (config-if)#exit
    (config)#exit
    
    #sh dot11 bssid
    Interface      BSSID         Guest  SSID
    Dot11Radio0   0026.0bXX.XXXX  Yes  Guest
    Dot11Radio1   0007.7dXX.XXXX  No   Example
    
    #
    

    EDIT: Corrected myself, it does work on a dual radio AP, but not single radio

    FYI on a WLC you can assign multiple SSIDs to a single VLAN. However, on a WLC - you're not really assigning the SSID to VLAN, but instead assigning it to an interface group which then, assigns itself to the appropriate vlan via tagging or native....you can also specify backup ports too!

    Thanks for the info hestonk! I haven't had the opportunity to use a WLC yet. Hopefully soon! The experience would be a nice addition.

    so I've actually just come across this exact issue on a dual-band AP - You can have 2 different SSIDs running on the same vlan HOWEVER that is because they're running on different radios. I still have the same issue as the OP where you can't run different SSIDs on the same VLANs....annoying!

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Content dated before 7/24/2021 11:53 AM

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