Cisco 3825 with Integrated WLC

Unanswered Question

Hi All,

I am having cisco3825 with integrated WLC. I have successfully registered LAP with the WLC and its working.

Now I am making slight change in the connectivity between router and LAP, I am installing a L3 switch (with multiple L3VLANs) between router and the LAP.

Earlier I was having a L2 switch and AP was also in the L2 VLAN.

I want to know:

1) Will it make any difference if the AP is conected to L3 Vlan instead of L2.

2)Is it important to have sub-interface Integrated service-engine 0/0.40 (where 40 is the VLAN id of the AP.

Can I have different Vlan id for sub-interface service-engine as against L3 Vlan id.

In brief I am not able to understand the traffic flow between AP and the WLC when L3 switch will come in between router and AP.

Thnx n Rgds,


I have this problem too.
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I feel that the moment AP gets registered with the WLC an tunnel gets prepared and all the wireless clients than reach the WLC through this tunnel only and they by pass router's Ethernet interface connected with the AP. Kindly let me know of this understanding is incorrect.

If I am correct, kindly let me know:

What is this tunnel? L2 or L3? And elaborate pls.

Would be delighted if you could add more to my knowledge.

Thnx n Rgds,


Scott Fella Mon, 04/20/2009 - 04:14

There is an LWAPP tunnel (UDP 12222 or 12223) that gets created from the AP to the WLC. Since the AP has an ip address, it doesn't matter if the ap is on the same subnet or a diffrent subnet, since it communicates through ip (L3). The WLC must be configured for L3 and not L2 which is only supported by the original Airspace 1000 series ap's.

If you already had the ap's join the wlc, then moving them to a different subnet should not be an issue. As long as the ap's can get an ip address and has a route back to the wlc, they should join right up. Since the ap has already joined the wlc, it knows of that wlc ip address and wil contact the wlc through its default gateway. Hope this helps clarify things.

Scott Fella Sun, 04/19/2009 - 17:01

AP's can be in a different subnet than the WLC. Are you making the switch do all the internal routing and then have a L3 connection from the switch to the router? As long as the AP has an IP and a route back to the WLC, everything should work.


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