WLC and LWAP initial setup

[bevans]

I am having some issues with the initial setup of a 4402 WLC and 35 Cisco Aironet LWAPPs. The WLC and the LWAPPs are configured in the same VLAN and a DHCP server is setup to serve the VLAN. The WLC is configured for LAYER2. The LWAPPs show link light on the switches they are plugged in to... but I cannot see them from the WLC. Any thoughts?

[ericgarnel]

Put the controller in Layer3 mode & reboot and they should start getting ips. I did this back in 3.2x code, maybe it has changed in 4.1.x, but that was how I was able to get ip addrs assigned to the APs.

[steve.busby]

In your original post you stated "...a DHCP server is setup to serve the VLAN...". Is the DHCP server actually in VLAN 203? If not, then you will need an IP helper address on your Layer 3 interface for VLAN203 which points to the DHCP IP address.

Provided your LWAPPs and WLC are both in the same VLAN, you shouldn't need to use DHCP Option 43. But it won't hurt to include it for some extra insurance.

HTH

Steve

[bevans]

Thanks for your post.

The DHCP server is not in the same VLAN. The ip-helper is configured. When I reset one of the APs I see it come up (in show cdp neighbors) and then disappear after a short time. It never recevies an IP. However, a laptop/PC will. Any thoughts?

[jwadleigh]

Hi!

You shouldn't need either option 43 or 60 for DHCP, given your configuration. Also, you won't need to convert to L3 operation.

It sounds like the real problem here is with your AP's not receiving a DHCP response. Of course, IP connectivity is a prerequisite for LWAPP Discovery.

Here are a few things to look at:

1.) Is the DHCP server in the same network (VLAN203)? If not, is the appropriate helper address provided on the gateway?

2.) Is there a DHCP scope established for VLAN203? Confirm that the addresses are in the right network, that the subnet mask is correct, and that the default gateway also corresponds to the subnet.

3.) Is the DHCP server receiving the request? Maybe a trace would shed some light.

Hope this helps! Good luck, and let us know how you did!

[bevans]

Thank you... I found a silly error on my part. However, the APs are still not registering. I have reset the APs and the WLC and the APs now have IP addresses but will not register. I can ping the APs but that is it. Any thoughts?

[jwadleigh]

We can assume from past posts that you have the AP-Manager and Management interfaces on the same network (VLAN203) as the access port for your AP.

Have you tried to console into the AP directly (via the console port)? If you do this on startup you can confirm whether you have an IOS or LWAPP AP. (I know, it seems silly; but let's eliminate the obvious.)

Okay, assuming the above, let's go through the LWAPP process and see if we can figure it out...

1.) BROADCAST: This will work if the AP-Switch port is on the same subnet as the WLC Management interface.

2.) CONFIGURED: Not applicable because this AP has never been registered to this controller.

3.) OTAP: Not an option for us until we get at least one AP registered.

4.) DHCP: If you enable option 43, it will provide a unicast address for your WLC.

5.) DNS: I'm assuming that this lab environment does not have DNS available, so creating an entry for cisco-lwapp-controller.localdomain is not an option.

So, we're left with the dynamic LWAPP discovery process.

Unplug your AP from its power source (or switch port if PoE is enabled). Console into your controller (telnet, SSH, service port, etc.). Type the following:

debug lwapp events enable

Now power up the AP. Did anything come up on the controller console indicating that an LWAPP DISCOVERY REQUEST was detected? If not, then we still have a connectivity issue. I hate to beat a dead horse; but I'd take a fresh look at your switch port configs.

If you did see the LWAPP Discovery request, it should be followed by an LWAPP DISCOVERY RESPONSE. Type the following:

debug lwapp packet enable

Toward the bottom of the packet you should see info regarding the IE. The line after the 'Decode routine' line has a number. The last two digits indicate which LWAPP discovery mechanism is being used per the following list:

00: Broadcast

01: Configured

02: OTAP

03: DHCP

04: DNS

Does this shed any light at all? Don't worry; we'll get there. 🙂

[bevans]

Thank you for your thorough and detailed post!

I tried the "debug lwapp events enable" and nothing appeared on the WLC console. To confirm my network config....

WLC port connection config (CAT OS):

set trunk 3/4 on dot1q 1-1005,1025-4094

AP port connection config:

interface FastEthernet0/9

description Cisco LWAPP

switchport access vlan 203

spanning-tree portfast

Any thoughts? Thanks!

[jwadleigh]

Do you have physical access to the AP? If so, use a console cable to term into the CLI. (If you do this before power cycling the AP, you can watch the boot sequence to confirm that LWAPP is loading properly.)

I'm still concerned about the AP network connectivity. It could be that there's some sort of problem with the DHCP response or the response is not in the correct subnet for vlan203.

You said that you can ping the IP address of the AP. Just to rule something else out; try manually configuring IP info on the AP.

Via the console port of the AP:

lwapp ap ip address

lwapp ip default-gateway

lwapp controller ip address

Once these are set, save the config and power cycle the AP.

Also, do you have the AP-Manager interface in vlan203 with IP information which matches that subnet?

Is vlan203 the native vlan of the trunk?

Do you have the Management interface and AP_Manager interface tagging traffic for vlan 203?