CAP3502E not joining WLC 5508

[mcaoile]

Hi,

I am wondering why the APs don't join the controller even though the APs and WLC are in the same subnet (VLAN245).  I consoled to the AP and there was a message   '%CAPWAP-3-ERRORLOG: Not sending discovery request AP does not have an Ip'.  I connected my laptop to the port where the AP is connected and I get an IP (see attached).  If I put a static IP, the AP will join the WLC.  I am attaching some capture hoping it can be of help.

Regards,             

[Scott Fella]

A couple things... You posted a dhcp scope on the WLC. The WLC will not hand out IP address to wired clients. So if your laptop got an IP address, it must be from an external dhcp.

Is it a problem with one AP? Do you have other APs that have joined. What is the configuration for the switch port the WLC is connected to and what is the configuration that the ap is connected to.

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[mcaoile]

Hi Scott,

It's a problem on some APs.  Some APs got an IP from the WLC.  I checked the DHCP lease and it shows the mac address of the laptop with the leased IP address.

For AP port: 

            interface GigabitEthernet1/0/45

              switchport access vlan 245

              switchport mode access

              mls qos trust dscp

              spanning-tree portfast

For WLC port:

interface Ethernet2/16
  switchport mode trunk
  switchport trunk allowed vlan 231-237,244-245
  speed 1000
  channel-group 100

The Access switch is a 3750 and the core switch is a Nexus 5K (were WLC is connected)

Regards,

[Scott Fella]

Here is a doc to help troubleshoot

http://www.cisco.com/en/US/products/ps6366/products_tech_note09186a00808f8599.shtml

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[mcaoile]

Hi Scott,

What is the meaning of this message in the debug client?

%CAPWAP-3-EVENTLOG: Could not discover any MWAR

Regards,

[Scott Fella]

Don't really know the meaning of that error. Can you post the whole boot up process.

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[mcaoile]

Hi Scott,

Please see attached bootup capture.

Regards,

[Leo Laohoo]

AP is not getting an IP Address.

You can assign an IP address (temporarily) to be able to join the controller using the command "capwap ap ip address ".

Again, you need to figure out why the AP is not getting a DHCP lease in the first place.  Because once the AP joins, it will download the software and configuration and possibly reboot after that.

[mcaoile]

Hi Leo,

I did assign a static IP and the AP joined the controller.  When I removed the static IP in the AP properties, the AP rebooted and can't get an IP.  That's what I can'y figure out why some APs don't get an IP and some are getting an IP. As an example, in 1 switch I have 3 APs connected, 2 are getting an IP and the other is not getting an IP.  I tried to put the AP in the port that an AP is getting an IP and it is not getting the IP.

Regards,

[Leo Laohoo]

What appliance is doing your DHCP?

Can you get your core switch to host the DHCP scope for the AP using Option 43?

Can you also configure the CISCO-CAPWAP-CONTROLLER DNS values?

[mcaoile]

Hi Leo,

I set the WLC as the DHCP server since the AP and the WLC are in the same subnet.  I have attached in the original post the DHCP pool config in the WLC.  The core switch is a Nexus 5K and according to the network engineer who configured the Nexus 5K, it does not support DHCP pool, that is why I configured the WLC as the DHCP server.  Is there any missing configuration in the way I have setup the pool in the WLC?

Regards,

[Leo Laohoo]

I set the WLC as the DHCP server since the AP and the WLC are in the same subnet.

Ummmm ... That ain't going to work.  For two reasons:

1.  WLC's DHCP function is very, very simple.  It's mainly used to provide DHCP scope for WLAN users and not for AP.

2.  You need to set DHCP Option 43, which the WLC's DHCP won't be able to support either.

The core switch is a Nexus 5K and according to the network engineer who configured the Nexus 5K, it does not support DHCP pool, that is why I configured the WLC as the DHCP server.  Is there any missing configuration in the way I have setup the pool in the WLC?

Use one of your switches as a DHCP server and configure "IP helper address" of the VLANs where the APs are on to the IP address of that switch.

[Scott Fella]

Leo... The WLC can provide dhcp to access points:) You just need a dynamic interface on that vlan that the AP's are connected to and you also need dhcp proxy enabled for the WLC to be able to be a dhcp server.

I would usually test by placing the AP's in the same subnet as the WLC management and have a dhcp scope on that subnet configured on the WLC. This eliminates any issue with an external dhcp server for my test. I would also try an external dhcp server to test with also. This test if there is an issue with the WLC dhcp.

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[Leo Laohoo]

Cool!  Thanks Scott.

[Scott Fella]

Non problem Leo... I learned this because a client wanted to have this design that the WLC handed out the IPs to all access points. Well I was surprised it worked:)

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