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Occasional Contributor II
Posts: 87
Registered: ‎11-27-2014

AP join query

[ Edited ]

Hi all,

 

I've been performing some low level testing of the AP join process to improve my understanding of the process involved. Whilst it is well documented in these forums in existing posts, I have come across a rather stange scenario that I'm struggling to understand.

 

The scenario I have created is this:

 

I have a single controller configured with a single Vlan172. This Vlan is defined as my controller-ip, has a layer 2 interface defined, 172.31.248.2. I have also defined a DHCP scope that does not have any DHCP options configured, it is just providing an IP address for the AP. On the controller I have also disabled ADP discovery and ADP igmp-join. The issue I have is when consoled into the AP I see the AP correctly obtain an IP address, and it states that it is running ADP and finds the master? In Wireshark I see the AP using ICMPv6, and still issuing multicast requests, what I don't see is anything coming back from the AMC. The AP is then able to join the controller. It is obviously layer 2 adjacenet to the AMC, but I can't figure out how it has joined?

 

Can somebody please explain? I know this is very basic, I'df just like a full understanding :)

 

Thanks

Guru Elite
Posts: 21,274
Registered: ‎03-29-2007

Re: AP join query

Do you have a DNS server configured with an "Aruba-Master" A-record?

 



Colin Joseph
Aruba Customer Engineering

Looking for an Answer? Search the Community Knowledge Base Here: Community Knowledge Base

Guru Elite
Posts: 21,274
Registered: ‎03-29-2007

Re: AP join query

Secondly, console into the AP and stop it at the apboot> prompt.  Type DHCP and press enter.  Please post the output.



Colin Joseph
Aruba Customer Engineering

Looking for an Answer? Search the Community Knowledge Base Here: Community Knowledge Base

Occasional Contributor II
Posts: 87
Registered: ‎11-27-2014

Re: AP join query

Hi,

 

No, all I have in my lab is my 3600 and a Cisco switch. No DNS. I had an old version of code on it originally so upgraded to 6.4.2.13 but get the same result. It is odd as in my production networks I don't see this.

 

Going back to it tonight so can post the output from the AP and packet capture from port and to the controller.

 

I wasn't sure if when the AP suggested it had run ADP that this was what it had actually used to find the AMC, and there wasn't another process running in the background. If there is, I didn't see this in the capture. I also reset the AP back to factory defaults (AP225) to rule this out. But got the same.

Occasional Contributor II
Posts: 87
Registered: ‎11-27-2014

Re: AP join query

Sure, will do

Guru Elite
Posts: 21,274
Registered: ‎03-29-2007

Re: AP join query

Also, on the controller, what is the output of "show adp config"?

 



Colin Joseph
Aruba Customer Engineering

Looking for an Answer? Search the Community Knowledge Base Here: Community Knowledge Base

Occasional Contributor II
Posts: 87
Registered: ‎11-27-2014

Re: AP join query

Hi,

 

Output as requested...

Guru Elite
Posts: 21,274
Registered: ‎03-29-2007

Re: AP join query

If you are supplying Dhcp with the controller it automatically inserts the dhcp option.


Colin Joseph
Aruba Customer Engineering

Looking for an Answer? Search the Community Knowledge Base Here: Community Knowledge Base

Occasional Contributor II
Posts: 87
Registered: ‎11-27-2014

Re: AP join query

Right, ok.

 

So in the attached I have provided my DHCP config on the controller and the output of the DHCP DORA between the AP and the AMC. I can see option 60 being returned by the controller, but not option 43, I thought it was option 43 that defined the IP for the AP use to terminate the tunnel on? Is there a different option included in the offer that it uses? The only one I can see is option 54 which I don't have configured in my scope.

 

Can you please elaborate on how this works just to clear it up in my mind?

Guru Elite
Posts: 21,274
Registered: ‎03-29-2007

Re: AP join query

[ Edited ]

DHCP option 43 and 60 are both in the capture.  Please look at the option 43 field in ASCII.  That is hardcoded into the background of every dhcp lease on the controller

http://www.arubanetworks.com/techdocs/ArubaOS_64x_WebHelp/Web_Help_Index.htm#ArubaFrameStyles/DHCP_Option_43/Windows_Based_DHCP_Serve.htm?Highlight=dhcp option



Colin Joseph
Aruba Customer Engineering

Looking for an Answer? Search the Community Knowledge Base Here: Community Knowledge Base

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