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DHCP through a Cisco 4400 interface / AP group

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Jan 17, 2007
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I have 4 dynamic interfaces on my Cisco 4400 controller. Each interface IP address is on a different subnet. For example:

interface one (Int1) on VLAN 201 at 10.10.201.200
interface two (Int2) on VLAN 202 at 10.10.202.200
interface three (Int3) on VLAN 203 at 10.10.203.200
interface four (Int4) on VLAN 204 at 10.10.204.200

I then have a single WLAN defined:

Profile name = MY_SSID
WLAN SSID = MY_SSID

(Note: if the name and SSID do not match, there's a bug that prevents the SSID's from broadcasting when the WLAN override is enabled. Let's not use the override for this example.)

I then have 4 AP Groups defined and on each one the WLAN SSID assigned is MY_SSID (it's the only one). I then put some radios in one AP Group, some in another AP Group, etc until all 4 Groups have a few radios. (Do this by WIRELESS > All APs > Pick a radio's "Detail" link and use the AP Group dropdown box.)

So here's the theory: I go near a radio in Group 1 and fire it up. It hits interface Int1 and pulls an IP for that subnet/vlan. I can then roam to other subnets using that IP.

This works great. I boot near one group, I can roam all over the campus with my initial IP. I boot near another group, I pull a different IP and can roam with that one.

But near 2 of the groups I can't pull an IP. I can roam to these groups with IPs pulled from the other working groups, but I can't get an initial IP through them. So it can't be a networking issue since the roaming works.

Obviously I looked closely at the differences between the groups that work and those that don't both on the controller and on our domain controller (which supplies DHCP). None that I could see.

Any clues or pointers would be appreciated.

 
SOLVED!

I had trunked only 2 of the vlans from the core to the controller. I added the other 2 vlans to the trunk (actually I use LAG to run 2 etherchannel trunks from different switches in the core stack so I actually added them to the port-channel which added them to the trunks).

I can now pull an appropriate IP depending on which radio I start at, then I can roam with that IP everywhere.

OK, I admit it. That was stupid.

Now to shoot another SSID on only SOME radios. That will use WLAN override.

Remember, Cisco bug report (I mean caveat) says to make the SSID must match the WLAN name or override doesn't work (which I can confirm).
 
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