SSID dynamic interface mappings in AP groups

[vinibrunelli]

Hi everyone,

I would like to know how wlc works at a given situation:

We have the ap-group ¨ Students¨, and we want to use a /23 prefix divided into two /24 networks.

So we have created two interfaces mapping (vlan1 - 10.10.0.0/24 and vlan2 -10.10.1.0/24), then we put these interface-map on the ap-group Students, so we assined the AP at this ap-group.

When the first client connects on a SSID attached to this ap-group, witch one of this networks will be used firsrt?

So how the WLC will balance the clients on these two vlans? It will fullfield the vlan1 then start to use vlan2 or WLC will put one client on each vlan at each connection?

Thanks very much,

Best regards,

Vinicius Brunelli

[Rasika Nayanajith · Accepted solution]

Hi Vinicius,

If you use interface group (to map multiple vlans to single wlan), then it will use round-robin mechanism. That mean first clinet goes to vlan 1 & then next client go to vlan 2, and 3rd to vlan 1 & so on. Refer this document

https://www.cisco.com/c/en/us/support/docs/wireless/5500-series-wireless-controllers/113465-vlan-select-dg-00.html

Here is some other useful blog post on this feature

https://www.iptel.com.au/vlan-select-calculator-tool/

https://mrncciew.com/2013/01/27/understanding-vlan-select-feature/

HTH

Rasika

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[vinibrunelli]

Hi Rasika!
I was suspecting that the wlc works this way, but I didn't found any articles abot it, now it is, now it is clear to me.
Thank You very much!
Best regards,

[balaji.bandi]

First of all it not make any sense to split the network in to 2 /24 subnets, if they are 1 SSID and for same user groups, Until you have any specific use case, if so explain ?

[Leo Laohoo]

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@vinibrunelli wrote:

We have the ap-group ¨ Students¨, and we want to use a /23 prefix divided into two /24 networks.

So we have created two interfaces mapping (vlan1 - 10.10.0.0/24 and vlan2 -10.10.1.0/24), then we put these interface-map on the ap-group Students, so we assined the AP at this ap-group.

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STOP.  RIGHT.  THERE.  

Create two subnets.  Create two dynamic interfaces.  Bundle them together using interface groups.  

Create an AP group.  Choose the SSID and then assign the SSID to the AP Group.

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@balaji.bandi wrote:

First of all it not make any sense to split the network in to 2 /24 subnets, if they are 1 SSID and for same user groups, Until you have any specific use case, if so explain ? 

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 It doesn't make sense to me until we ran into trouble.  We're lucky for Interface Group feature because now we've been using it intensively.  One of the benefits about using this is we can "grow" the subnet as we like.  If the subnet gets full, no problem-o, just tack the new dynamic interface and add it to the interface group.  Viola!  

[balaji.bandi]

@Leo Laohoo

 It doesn't make sense to me until we ran into trouble.  We're lucky for Interface Group feature because now we've been using it intensively.  One of the benefits about using this is we can "grow" the subnet as we like.  If the subnet gets full, no problem-o, just tack the new dynamic interface and add it to the interface group.  Viola!  

Sure Agreed in broad point of view.