Access controller Topology question.

[Gerson Acevedo]

Hi.

I have a question regarding a basic access controller  and the AP topology.

Look the attached image.

My question is. I really need a cable connected to my switch for each SSID in the AP. Since each SSID= VLAN.

Or can I configure a trunk in the AP side to avoid a lot of cables?

Thank you.

[Moin Ilyas]

Please refer to the following links:

http://www.cisco.com/c/en/us/td/docs/wireless/controller/8-0/configuration-guide/b_cg80/b_cg80_chapter_01011100.html#ID2612

http://www.cisco.com/c/en/us/support/docs/wireless-mobility/wireless-vlan/71477-ap-group-vlans-wlc.html

[RockstarWiFi · Accepted solution]

So from WLC Ports (Physical Interfaces) to the Switch is almost always an 802.1Q trunk. You create WLC dynamic interfaces to distribute traffic on the LAN, but these are essentially VLAN dot1q tagged interfaces (logical interfaces) to allow wireless traffic to distribute to the appropriate wired VLAN. Most deployments I do typically configure link aggregation between the WLC and the switch which would be trunked, any load balancing must happen on the switch as the WLC doesn't support LB schemes. Essentially the connectivity is Physical WLC port(s), to Physical Switch Port(s) dot1Q is configured on the switch ports. Dynamic interfaces (logical) identify where to distribute WLAN traffic to the wired network. Long story short you map WLAN's to VLAN's.

This is a great community with lots of experts willing to assist, so welcome.

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[Gerson Acevedo]

That part make sense to me. From WLC to Switch we have a trunk. But what if an AP have 5 SSID it means 5 vlans. So I have to connect the AP to the switch. Since I have several SSID in the same AP. I should have a trunk between the AP and the switch right? Or an access port is used?

[RockstarWiFi]

No, the AP is connected to an Access interface should be the same VLAN as your WLC management interface or AP manager interface (these two could be the same, they are on newer controllers). Multiple wireless networks are encapsulated at the AP into CAPWAP which sends all that data to the controller to sort out (distribute to the appropriate VLAN). You just ensure your WLAN's are mapped to the correct dynamic interfaces which are mapped to VLAN's). 

The only time an AP needs to be connected to a trunk interface is if it's operating in a special mode like Flex Connect, Rouge Detector, or Autonomous, etc. As long as its centrally managed any WLAN traffic is put into CAPWAP and sent to the controller to distribute. Make sense?

Good luck, and ask questions. I have to hit the bed for tonight though:)

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[Gerson Acevedo]

I think I have it. So basically all my SSID traffic is send it to the WLC and then the WLC distribute the traffic to the correct VLAN using a TRUNK between the WLC and the switch. So basically works like this.