Roaming mulitple VLANs using a 4400?

[professorguy]

I have 4 different subnets where our couple dozen lightweight WAPs (cisco 1242s) live. They all connect to a CIsco 4400 wireless controller. However, when I define each of the four WLANs (each connects to a different logical interface) I want to use the same SSID so users can roam. No, says my controller, WLANs must have either different SSIDs or different authorization methods.

OK, so say they are different. How do I configure a client so it can roam? I obviously have to set it to connect to a particular SSID. I could put in 4 different wireless connections on the client which will work correctly to get them on the network in each location. But how will they roam?

I was assured that having the controller was going to allow roaming across vlans. But how is such a scheme set up?

[And before you mention having the same vlan all over campus, we route (Layer 3) between closets so no vlan can span everywhere.]

 

[Packet7]

Hi,

I have never configured this, but I think you need to use mobility groups with Layer 3 LWAPP. The link below explains the approach in more detail. It covers inter controller and across subnet roaming. I hope this helps.

http://cisco.com/en/US/products/ps6305/products_configuration_guide_chapter09186a008063ede0.html

Rgds,

John

 

[professorguy]

I have a single mobility group defined for all 4 WLANs. However, the client sees only the SSIDs which must be different for each subnet. So what must the *CLIENT* settings be? Do I have to set up the client to automatically connect to all 4 SSIDs and just let the it figure it out as it roams the campus? That seems pretty weak since it means four times the client setup and administration. And what happens when we grow to 14 subnets with WAPs? Every client will need an additional 14 different setups? Not good....

 

[Packet7]

Hi,

We utilize two SSIDs for our entire region. One for employees and one for guest access. We don't have mobility configured across offices because of the geographic boundaries, but we are using the same SSID. Do all your AP's hang off the same WLC? We also use the WCS w/ Templates to simplify administration. Let me know.

Rgds,

John

 

[professorguy]

All the APs report to our one and only WLC. We don't use WCS.

Ideally I'd like a data SSID and a voice SSID on each and every AP. The 4 different subnets (with 3 or 4 APs per) must have different SSIDs (so it seems from the WLC configuration) so that means 8 different SSIDs? And how would our phones which cannot be configured to pick up 4 different SSIDs (unlike a laptop which can) still roam between subnets?

And yet I was told, "Layer 3 roaming? No problem!" OK, so how's it actually done?

 

[professorguy]

OK, I see how it is supposed to work:

You create the interfaces for the vlans. Then you make only ONE wlan with ONE SSID. Then you go to "WLANS > AP Groups VLAN" and make 4 different AP Groups. Each of these groups can be set (use "Detail" link) to use the ONE SSID and use the correct interface. Do this 4 times, using the same WLAN SSID but a different interface each time.

Now the part that caused me to spend an hour with the TAC: After you have done this, go to the WIRELESS page, go to 802.11b/g > Network and turn "802.11b/g Network Status" to Enabled. For some reason, setting ap group vlans turns off the radio. Turn it back on and you should be all set.

Now a client can be set to connect to the ONE SSID and it can roam around vlans!

Thanks everyone.

 

[Packet7]

Excellent! Thanks for sharing. I'm glad you are all set.

Rgds,

John