ignoring discovery request - AP on dynamic client interface

[Simon Fahrnbauer]

Hi All,

I have a questing regarding the AP Management Port on the 5508.
At our customers side there are some FAT-APs and we want to migrate them to the controller.
There is no DHCP Service active on the network (security-restriction by our customer) and the FAT-APs and Clients are configured with a static IP.
There is no LAG active everything is on Port 1.

Now after upgrading one AP to lightwight-mode,... he cannot discover his WLC (thats ok, because the Manament Interface is in a different subnet)
So I configured a IP-Helper and the neccesary udp-Port to get the AP joined on the WLC.

But on the Controller I get the following message:

%CAPWAP-3-DISC_INTF_ERR2: Ignoring discovery request received on a 
wrong VLAN ([dec]) on interface ([int]) from AP 
[hex]:[hex]:[hex]:[hex]:[hex]:[hex]

The wrong VLAN in the message is a dynamic Interface on the Controller for client and the AP is in that Subnet.
It its created as an Dynamic Interface on the WLC (without "Enable Dynamic AP Management")

I hope you can give me a hint. I'm not sure if I should enable "Dynamic AP Management" on that Client Interface.
By the way, the AP can join when i configure the Controller IP via console on it. But that should not be the solution 

Thanks & 
Best regards,

Simon

[Nicolas Darchis]

Putting APs in the subnet of a dynamic interface and relying on broadcast discovery (although with the help of an ip-helper) is the wrong part ...

Dynamic interfaces on WLC are supposed to be clients subnets. Why do you have APs in there ?

What destination ip did you configure in your ip-helper btw ?

[Simon Fahrnbauer]

Hi Nicolas,

thanks for your reply.

I know, that this design is not "best practice".

Our customer has a LAN which has to be completly redesigned.

They use very huge subnets for their different production segments (255.255.240.0) and everything is in there.

The Autonomous AP Installation is in one of these huge network segments where the APs and the clients are in the same subnet..

Thats the background why this szenario is created.

I know that this design is absolutly unsatisfactory.
But thats the fact and I have to deal with this.

The helper is the WLCs Management Adress.

So what about the "ignoring discovery request" message.

Is there some possibility to get it work this way or is the only way to upgrade the APs via Console to get them to the controller.

I know the best way would be to get the APs in a new different subnet,...

regards,

Simon

[weterry · Accepted solution]

You are always going to see that error about discovery on the wrong interface as long as your AP's Broadcast discovery request flows into the WLC.  That request is on a client vlan so that WLC is telling you it is ignoring the request.

So if you have IP helper and the port forwarding, then your broadcast should also be relayed from the gateway to the WLC MGMT and I think everything should work.....      so maybe your ip helper isn't working correctly?

Exactly what port forwarding do you have enabled?

Maybe you only setup 5246 and 5247    but the AP is running an LWAPP Recovery image, meaning it discovers with port 12222 and 12223?

Either way, I think you can ignore the error, since you won't get rid of it (unless you can find a way to prevent the broadcasts from going into the WLC on that vlan)......   focus instead should be on making sure a discovery request gets to the WLC MGMT IP via the MGMT vlan....

[Simon Fahrnbauer]

Hi weterry,

thanks for your reply!

Yes, that what I thougt about it!

So you think, that the discovery messages which is the cause for the log message is not the one which is sent over the ip-helper?

I'm going to check the forwarding ports with our customer tomorow. I told him to enter only the LWAP-Ports (12222 and 12223)

Thanks for the hint!

I let you know if that is the solution!

Bye

Simon

[Simon Fahrnbauer]

Hi weterry,

so you are right, the log message wasn't caused be the discovery request with the helper.

I dnot know why the helper (or here on Nortel "Relay-Agents") havent worked.

So I now configure the DNS Server within the upgrade-tool and it works quite well!

Thanks a lot and good bye!