LAP not retaining configuration

[rahul nair]

Hello all ,

This is the second time in a couple of weeks i am facing the same issue.

I have some 1142-lap that i have to deploy in my office.

I have successfully deployed 5 out of 8 LAPs .

Actually the LAPs was not discovering the controller automatically.

So i had to configure the Controller ip adress through the console in tha AP using the CAPWAP command.

Then the AP promptly associates with the controller.

Later on i configure the AP name - Primary , Secondary , Tertiary Controllers and everything else and saved it on the controller.

This worked out well for the 5 LAPs that i had.

But started facing a peculiar problem with the rest three

As soon as i disconnect the AP from my desk and have it mounted on the celing , to my surprise if find that the LAP doesnt retain its configuration and also doesnt associate with the Controller.

Cant imagine what could be the issue.

I have been told that one CANT wite/save any configuration manually on tha LAP using the console, except by associating it with the controller.

Is it a fault with the AP ( as the other APs are working absolutely fine)

Pls help

Thanks in advance.

[rahul nair]

Some new things i noticed..

When i dismount the LAP and bring it on my desk , and then manually configure the Controller ip using the CAPWAP controller ip command...

1.It manages to connect to the controller.

2. But still ALL the LAP information such as the Hostname , Location , Pri/Sec/Ter controller information has disapperared again.

[Scott Fella]

Interesting. When you configure the APs, they are in the run state and not in a downloading state correct? Is it possible to mount it in the ceiling and configure the switchport to be on the same vlan as the wlc management port. Make sure there is dhcp. The ap should boot and obtain an ip address and then join the wlc. When it dies and it is in the run state on the wlc, can you then change the vlan to what you wanted the ap to be on.

Can you also console into the ap and post the output when it's on the same vlan and when it's not.

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[fbarboza]

Hi,

The LWAPP APs once we configure the static IP address, host name, etc it should retain the information.

Since it is LWAPP units they do not have the option of write mem.

If once the access point is mounted in the celling it is not able to join the WLC, then the issue could be configuration between the devices all the way from the AP to the WLC.

In this case the best option would be to get console access to the AP once it is connected to the port on the celling and enable debugs on the AP and WLC to see what the AP is doing and what the WLC is getting.

[Leo Laohoo]

Interesting indeed.

It sounds like the "private" config file is corrupt or something.

Can you run the following commands on the WAP?

1.  clear capwap private

2.  clear capwap ap ip address

3.  clear capwap ap hostname

REBOOT

[rahul nair]

thank you for replying guys.

@flar i ll capture the debug and paste it over here ,as soon as i visit the customer the next time.

BTW Update ......

We have managed a temporary workaround for this issue by assigning a static ip address IN THE SAMD SUBNET as the controller , and the ap does seem to reboot even afer a hadware restart.!!!

@scot...i ll do that too...but,

is it mandatory thay the ap and the controller needs to be in the same subnet/vlan.

please corrrect me if i am wrong.

[fbarboza]

Hi,

No you can have the access points either on the same subnet as the WLC or on a different subnet than the WLC.

If the access points are on the same subnet as the WLC, the AP once it gets an IP address from the DHCP server it will send a braodcast join request on the same subnet as the WLC and the WLC would reply back allowing the AP to join the WLC.

If the access point is on a different subnet then the WLC, than we will need to use a layer 3 discovery method so that once the access point gets and IP address it also knows the IP address of the WLC and instead of sending a broadcast request it will send a join request to the specifc WLC IP address to join.

You can use option 43 or DNS lookup

The last option we can use would be to configure a static IP address on the AP using the console port with the IP address of the default gateway and the WLC IP address to join.

Also if the APs are on a different subnet we need to make sure that either the LWAPP or CAPWAP ports are not blocked between the AP subnet and the WLC subnet by an ALC or firewall.

A. Follow these guidelines when you use CAPWAP:

• If your firewall is currently configured to allow traffic only from  access points that use LWAPP, you must change the rules of the firewall  to allow traffic from access points that use CAPWAP.

• Make sure that the CAPWAP UDP ports 5246 and 5247 (similar to the  LWAPP UDP ports 12222 and 12223) are enabled and are not blocked by an  intermediate device that could prevent an access point from joining the  controller.

• If access control lists (ACLs) are in the control path between the  controller and its access points, you need to open new protocol ports to  prevent access points from being stranded.

The access points use a random UDP source port to reach these  destination ports on the controller. In controller software release 5.2,  LWAPP was removed and replaced by CAPWAP, but if you have a new  out-of-the-box access point, it could try to use...

[Scott Fella]

No it's not mandatory it's just an easy way to get the APs to join.

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[George Stefanick]

Interesting post. I have a team member mention the same thing happen to her last week. I blew it off... Maybe I need to take a peek at this ..

[fbarboza]

Hi,

As mention the configuration file on the AP that stores the static information you set could be damaged.

here are the steps to reset the AP to defaults using the console port:

1.Desconect the AP from the network. 
2.Do a power cycle. 
3. When the access points loads the soiftweare log in (default password: Cisco)

4. Run the command: Show flash


    14  drwx 320   Mar 2 2002 03:14:32 +00:00 c1130-rcvk9w8-tar.123-11JX1
     4  drwx 256   Jan 20 2006 20:38:02 +00:00  c1130-k9w8-mx.123-7.JX2
    12  -rwx 525184   Mar 1 2002 00:00:32 +00:00  r1.rcore
     9  -rw    5777   Mar 7 2002 17:51:52 +00:00  login.html
    10  -rwx   1784   Mar 1 2002 23:21:56 +00:00  config.txt
    13  -rwx      5   Mar 1 2002 23:21:56 +00:00  private-config


If you see 2 images one is the recovery and looks like: 

c1130-rcvk9w8-tar.123-11JX1

There could be another image that is the image downloaded from the WLC and this one is 
the one we need to remove:

For erasing this image we use the command:


delete /recursive flash:

Example:

delete /recursive flash: c1130-k9w8-mx.123-7.JX2


This way the access point will reboot with the only available image in this case
c1130-rcvk9w8-tar.123-11JX1


But the private-config has not been erased (Here is where the AP IP and WLC IP is saved),
for erasing this we use the following command:


AP1240#clear lwapp private-config

After this we are able to reconfigure the AP with the correct information:


AP1240#lwapp ap hostname AP1240
AP1240#lwapp ap ip address 10.77.244.199  255.255.255.224
AP1240#lwapp ap ip default-gateway 10.77.244.220
AP1240#lwapp ap controller ip address 172.16.1.50