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New Member

Lightweight access point

Hello, I heard when an 3600 access point register for the first time to 5500 wireless controller it first get a dhcp IP address and then sends lwapp broadcast across the same subnet to where the wlc is located and the registers, however is it possible for access point to find its way to the wlc when both devices our on different vlans. On our network I have access point on one vlan and wlc on another vlan and it able register. We have layer 3 switches. So does both devices need to be on the same vlan to send lwapp broadcast or it just gets routed from one vlan to the wireless vlan? Thanks,
7 REPLIES
Cisco Employee

Hi,Looks like you heard this

Hi,

Looks like you heard this from someone who is still in stone age :D

 

Lwapp was the protocol used long back now it is capwap. Anything after 4.x code will use capwap protocol for the communication between AP and WLC.

 

AP and WLC can be in different VLANs. As long as there is network connectivity between these two VLANs AP will have no issue registering to the WLC.

 

HTH.

 

Thanks & Regards,

Ishant

 

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Hall of Fame Super Gold

I heard when an 3600 access

I heard when an 3600 access point register for the first time to 5500 wireless controller it first get a dhcp IP address and then sends lwapp broadcast across the same subnet to where the wlc is located and the registers, 

If your WLC and your AP are in the same subnet, yes, this is one mechanism. 

however is it possible for access point to find its way to the wlc when both devices our on different vlans.

Configure DHCP Option 43 and configure DNS settings for "CISCO-CAPWAP-CONTROLLER" or "CISCO-LWAPP-CONTROLLER".

 

Read this:  Lightweight AP (LAP) Registration to a Wireless LAN Controller (WLC)

New Member

We don't have option 43 and

We don't have option 43 and is still works with two vlans how is that possible?

Hall of Fame Super Gold

We don't have option 43 and

We don't have option 43 and is still works with two vlans how is that possible?

Try deleting the entire configuration of the AP (Command:  clear capwap private) and reboot the AP.  Make sure the AP is in a different subnet as the WLC and see if the AP can join the AP.  

 

Maybe the AP can join the controller even in a separate VLAN because you've already "primed" the AP.  The AP now has the details (like the IP Address of the WLC Management Interface) it doesn't need DHCP Option 43 to begin with.

I am guessing Leo meant

I am guessing Leo meant "Configure DHCP Option 43 OR configure DNS settings for..."


We've recently deployed another couple of dozen APs and, as expected, with new out of the box APs it works with the DNS entry in place even if DHCP Option 43 is not set.

New Member

Hi Horacio, It depends on the

Hi Horacio,

 

It depends on the method we are using for the AP joining the and the code on the WLC.

If the WLC is at 4.x code it would only support LWAPP.

If the WLC is at 5.x or above it will support CAPWAP in which layer 3 is supported.

 

Now for the AP and the WLC in different vlan/subnet it depends for the APs using the joining process.The common AP joining process used are:

1. DHCP Option 43

2. DNS

3. Priming

We need to to which of the joining process is used in your network. In case you are not using any specafic joining process, the entire process would be based on the broadcast sent by AP and then the Unicast sent by the WLC.

 

Thanks and regards,

Manas Pratap Singh

No, it is not necessary that

No, it is not necessary that both devices need to be on the same vlan to send lwapp broadcast or it just gets routed from one vlan to the wireless vlan

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