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Explorer

Mixing AP models - DHCP vs. DNS for Controller Discovery

Hello,

I'm adding some additional AP's (3502s) to an environment that is all 1131AG AP's.  The DHCP is configured for DHCP option 43 for remote sites for layer 3 discovery.  Since only one AP mode can use option 43, I've added a DNS entry for cisco-lwapp-controller in my local domain.


My assumption here is that the new 3502's will be able to use DNS for discovery, while any additional 1131AG would continue to use DHCP option 43.

Will this work in a mixed environment?

The new AP briefly showed up on my controller, but then disappeared.  The LED is cycling red, green, off - indicating it is still in the discovery process.

Could I effectively remove the option 43 in DHCP and have all AP's use DNS?  Is this as reliable as option 43?  What is the best practice for discovery?

Thanks,

Rob

6 REPLIES 6
Cisco Employee

Re: Mixing AP models - DHCP vs. DNS for Controller Discovery

Hi Rob,

Yes there is no problem in mixing the APs..  however, if we are using the dedicated DHCP server instead os running on  the IOS, then we can do it.. else as well most of the time this works  fine on IOS as well.. here is the another option as wll... if we are  running 12.4.11T or higher..

ip dhcp class aironet-1130
    option 60 ....<- VCI from 1130 AP

ip dhcp class aironet-3500
    option 60 ....

ip dhcp pool all-ap-models
    network 10.1.2.0
    class aironet-1130
        option 43 ...
    class airespace
        option 43 ... <- 3500


Here is the link to do it on the server

http://www.cisco.com/en/US/tech/tk722/tk809/technologies_configuration_example09186a00808714fe.shtml#t1

I guess mixing the DNS and the option 43 works as well..

lemme know if this answered your question..

Regards
Surendra
====
Please dont forget to rate the posts which answered your question and mark it as answered or was helpfull

Regards
Surendra BG
Explorer

Re: Mixing AP models - DHCP vs. DNS for Controller Discovery

Finally found a serial cable and the answer became very clear.  The 3502 was looking for cisco-CAPWAP-controller not cisco-LWAPP-controller.

Changed the DNS record and everything is rocking.

Thanks for the help!

Mixing AP models - DHCP vs. DNS for Controller Discovery

Hi rcoote5902

I'm in the same boat now as the 3502i AP is not associating with the controller...all the option 43 and DHCP are correct. Can you please advise how you did the DNS record change for CAPWAP

Thanks

Explorer

Re: Mixing AP models - DHCP vs. DNS for Controller Discovery

Hi Chandra,

Switching to using DNS for discovery became a much better solution for us overall as we have now also mixed in some AP's from another vendor (Ruckus) and they also use a DNS discovery.

From this guide:

http://www.cisco.com/en/US/docs/wireless/controller/5.2/configuration/guide/Controller52CG.html

"DNS discovery—The access point can discover controllers through your domain name server (DNS). For the access point to do so, you must configure your DNS to return controller IP addresses in response to CISCO-LWAPP-CONTROLLER.localdomain, where localdomain is the access point

domain name. When an access point receives an IP address and DNS information from a DHCP server, it contacts the DNS to resolve CISCO-LWAPP-CONTROLLER.localdomain. When the DNS sends a list of controller IP addresses, the access point sends discovery requests to the controllers. "

This example uses LWAPP but it's the same for CAPWAP.  All you need to do is add an A record to your domain DNS server for "cisco-capwap-controller.localdomain" (using whatever your local domain actually is) and the AP's will use this for discovery.

We also added an A record for "zonedirector.localdomain" which the Ruckus AP's use for discovery so regardless of which AP's we use where, they always contact the correct controller.

I hope this helps!

Rob

Mixing AP models - DHCP vs. DNS for Controller Discovery

Thanks Rob...I think the DNS/DCHP stuff working OK but still have the same problem...here are the logs

Mar  1 00:11:04.709: %LINK-3-UPDOWN: Interface Dot11Radio1, changed state to up
*Mar  1 00:11:04.803: %LINK-3-UPDOWN: Interface Dot11Radio0, changed state to up
*Mar  1 00:11:05.630: %LINEPROTO-5-UPDOWN: Line protocol on Interface Dot11Radio1, changed state to up
*Mar  1 00:11:05.630: %SYS-6-LOGGINGHOST_STARTSTOP: Logging to host 255.255.255.255 started - CLI initiated
*Mar  1 00:11:05.721: %LINEPROTO-5-UPDOWN: Line protocol on Interface Dot11Radio0, changed state to up
Translating "CISCO-CAPWAP-CONTROLLER.xxx.xxx"...domain server (x.x.x.x) [OK]

*Mar  1 00:11:12.022: %CAPWAP-5-DHCP_OPTION_43: Controller address x.x.x.x obtained through DHCP
*Aug  9 05:10:08.000: %CAPWAP-5-DTLSREQSEND: DTLS connection request sent peer_ip: x.x.x.x peer_port: 5246
*Aug  9 05:10:08.000: %CAPWAP-5-CHANGED: CAPWAP changed state to 
*Aug  9 05:10:08.427: %CAPWAP-5-DTLSREQSUCC: DTLS connection created sucessfully peer_ip: x.x.x.x peer_port: 5246
*Aug  9 05:10:08.427: %CAPWAP-5-SENDJOIN: sending Join Request to x.x.x.x

*Aug  9 05:10:08.430: %CAPWAP-5-CHANGED: CAPWAP changed state to JOIN
*Aug  9 05:10:08.616: %CAPWAP-5-CHANGED: CAPWAP changed state to CFG
*Aug  9 05:10:08.622: %DTLS-5-ALERT: Received WARNING : Close notify alert from x.x.x.x

*Aug  9 05:10:08.622: %DTLS-5-PEER_DISCONNECT: Peer x.x.x.x has closed connection.
*Aug  9 05:10:08.622: %DTLS-5-SEND_ALERT: Send FATAL : Close notify Alert to x.x.x.x:5246
*Aug  9 05:10:08.682: %CAPWAP-5-CHANGED: CAPWAP changed state to DISCOVERY
*Aug  9 05:10:08.682: %CAPWAP-5-CHANGED: CAPWAP changed state to DISCOVERY
*Aug  9 05:10:08.767:  status of voice_diag_test from WLC is false
*Aug  9 05:10:19.000: %CAPWAP-5-DTLSREQSEND: DTLS connection request sent peer_ip: x.x.x.x peer_port: 5246
*Aug  9 05:10:19.000: %CAPWAP-5-CHANGED: CAPWAP changed state to 
*Aug  9 05:10:19.427: %CAPWAP-5-DTLSREQSUCC: DTLS connection created sucessfully peer_ip: x.x.x.x peer_port: 5246
*Aug  9 05:10:19.427: %CAPWAP-5-SENDJOIN: sending Join Request to x.x.x.x

*Aug  9 05:10:19.427: %CAPWAP-5-CHANGED: CAPWAP changed state to JOIN
*Aug  9 05:10:19.607: %CAPWAP-5-CHANGED: CAPWAP changed state to CFG
*Aug  9 05:10:19.613: %DTLS-5-ALERT: Received WARNING : Close notify alert from x.x.x.x

*Aug  9 05:10:19.613: %DTLS-5-PEER_DISCONNECT: Peer x.x.x.x has closed connection.

Highlighted
Explorer

Re: Mixing AP models - DHCP vs. DNS for Controller Discovery

It looks like DHCP is working for controller discovery but the controller or AP is failing the config process. There should be a log on the controller as well, does it provide any more details?

Sent from Cisco Technical Support iPhone App

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