AP2802 cannot join WLC

[Rps-Cheers]

Hi everyone,

i have met a issue that is AP2802 cannot join WLC.

AP model:AIR-AP2802I-H-K9

software:8.3.143.0

WLC release:8.3.143.0

AP get the ip address by DHCP. the log as below:

ethernet_port wired0, ip 10.1.1.30, netmask 255.255.255.0, gw 10.1.1.254, mtu 1500, bcast 10.1.1.255, dns1 10.1.2.11, dns2 192.168.3.11, domain cn.daliang.comDOT11_DRV[1]: set_channel Channel set to 36

There are some abnormal message:

[*12/06/2018 22:00:40.8805] CAPWAP State: Discovery
[*12/06/2018 22:00:40.8854] Discovery Request sent to 255.255.255.255, discovery type UNKNOWN(0)

after i config the WLC sysname and ip address,also have these abnormal message：

[*12/06/2018 22:03:17.8061] Discovery Request sent to 192.168.2.100, discovery type STATIC_CONFIG(1)
[*12/06/2018 22:03:17.8070] Discovery Request sent to 192.168.2.101, discovery type STATIC_CONFIG(1)
[*12/06/2018 22:03:17.8071] Got WLC address 192.168.2.101 from DHCP.
[*12/06/2018 22:03:17.8104] Discovery Request sent to 192.168.2.100, discovery type STATIC_CONFIG(1)
[*12/06/2018 22:03:17.8112] Discovery Request sent to 192.168.2.101, discovery type STATIC_CONFIG(1)
[*12/06/2018 22:03:17.8121] Discovery Request sent to 255.255.255.255, discovery type UNKNOWN(0)

Could you help me to reslove this issue.

Thanks.

[patoberli]

DHCP Option 43 should also work.

Make sure you also have set the correct primary gateway in the DHCP options. Do you have set any other options?

There is a possibility with another option to limit the Option 43 for only certain models of APs, I currently don't remember which option that was, but it's only a problem if it's configured.

[cmarva]

it depends on what you are using for a dhcp server. But you have to define the VCI for the 2800, I think it is CiscoAP2800 or something like that, just search for dhcp option 43 on CCO and you can find the doc that explains this and also lists the VCI for the different models of APs.

[patoberli]

I don't use the VCI with my 2800 and have no problem. My APs are in the same VLAN as the AP Manager interface though and for backup reasons I've also added the DNS entry :)

[Rps-Cheers]

There are some logs from ap:
Username: [*11/03/2019 20:01:03.5505] WTP IP address changed from 0.0.0.0 to 192.168.4.100, restart CAPWAP.
[*11/03/2019 20:01:03.5505]
[*11/03/2019 20:01:03.5505]
[*11/03/2019 20:01:03.5505] Lost connection to the controller, going to restart CAPWAP...
[*11/03/2019 20:01:03.5505]
[*11/03/2019 20:01:03.5505] Restarting CAPWAP State Machine.
[*11/03/2019 20:01:03.5506] Discarding msg CAPWAP_WTP_EVENT_REQUEST(type 9) in CAPWAP state: Discovery(2).
[*11/03/2019 20:01:03.5512]
[*11/03/2019 20:01:03.5512] CAPWAP State: DTLS Teardown
[*11/03/2019 20:01:07.3025]
[*11/03/2019 20:01:07.3025] CAPWAP State: Discovery
[*11/03/2019 20:01:07.3037] Discovery Request sent to 192.168.2.55, discovery type STATIC_CONFIG(1)
[*11/03/2019 20:01:07.3070] Discovery Request sent to 192.168.2.56, discovery type STATIC_CONFIG(1)
[*11/03/2019 20:01:07.3071] Got WLC address 192.168.2.56 from DHCP.
[*11/03/2019 20:01:07.3104] Discovery Request sent to 192.168.2.55, discovery type STATIC_CONFIG(1)
[*11/03/2019 20:01:07.3113] Discovery Request sent to 192.168.2.56, discovery type STATIC_CONFIG(1)
[*11/03/2019 20:01:07.3129] Discovery Request sent to 255.255.255.255, discovery type UNKNOWN(0)
[*11/03/2019 20:01:16.8048]
[*11/03/2019 20:01:16.8048] CAPWAP State: Discovery
[*11/03/2019 20:01:16.8061] Discovery Request sent to 192.168.2.55, discovery type STATIC_CONFIG(1)
[*11/03/2019 20:01:16.8070] Discovery Request sent to 192.168.2.56, discovery type STATIC_CONFIG(1)
[*11/03/2019 20:01:16.8071] Got WLC address 192.168.2.56 from DHCP.
[*11/03/2019 20:01:16.8104] Discovery Request sent to 192.168.2.55, discovery type STATIC_CONFIG(1)
[*11/03/2019 20:01:16.8112] Discovery Request sent to 192.168.2.56, discovery type STATIC_CONFIG(1)
[*11/03/2019 20:01:16.8121] Discovery Request sent to 255.255.255.255, discovery type UNKNOWN(0)

[patoberli]

It sees two WLC:
[*11/03/2019 20:01:07.3104] Discovery Request sent to 192.168.2.55, discovery type STATIC_CONFIG(1)
[*11/03/2019 20:01:07.3113] Discovery Request sent to 192.168.2.56, discovery type STATIC_CONFIG(1)



Also the date/time is wrong (or the output is very old), make sure the WLC is synchronized by NTP!



Can you output a show version from this AP?

[Leo Laohoo]

Time & date is wrong.

[Rps-Cheers]

i don't think so,i have checked the time of wlc and ap...but i didn't find abnormal about this.and some many aps are working well..

[patoberli]

The correct time is critical if an AP needs to associate to the WLC. Once it's attached, it doesn't really matter if the time is correct, but for association (join) it's needed to be correct.
On your log output, the date is from March or November (depending on the date format), but not May.

[Leo Laohoo]

Enable NTP or else the AP won't join. 

The correct (and accurate) time and date may not seem important but it is vital to a WLC.  

[Rps-Cheers]

I am sorry,what's is VCI,is it DHCP Option 43 Vendor Class Identifier (VCI) ? If so,i configure dhcp server by cisco document as below:https://www.cisco.com/c/en/us/support/docs/wireless-mobility/wireless-lan-wlan/97066-dhcp-option-43-00.html

[Rps-Cheers]

I don't have any other config of dhcp,at the beginning,i don't config the dhcp option43,other aps can work noraml after obtain ip address from dhcp server,only ap2802 need configure wlc's ip address by "capwap ap ..." command,then,it can be work.So,i doubt whether ap16 & ap27 discovery process difference with ap2800.But i didn't find any reason to explain this symptom,because i didn't face this issue before.