H-REAP AP keeps associating/disassociating from WLC

Inayat Bunglawala · ‎06-19-2012

Hi everyone,

I have an H-REAP AP based in Singapore but in central authentication and central switching mode and connected to a Wireless LAN Controller in London. Unfortunately, the AP keeps associating and then disassociating from the WLC, sometimes every 10 minutes or so and sometimes it remains connected for a couple of hours without disconnecting.

I have enabled the Link Latency on the WLC for this AP and it shows that the usual ping time is around 210-220ms (so within the 300ms limit as I understand it for H-REAP APs) but the maximum latency does exceed this and can be 800ms-1300ms. Unfortunately, the Link Latency values are not time stamped so I have not correlated whether the disconnections are happening when the latency is exceeding the Cisco recommended value.

The WLC logs do not seem to provide any clue as to why the AP is misbehaving. I have noticed that each time a disconnection occurs the WLC reports a message similar to the following:

*spamReceiveTask: Jun 19 12:06:49.880: %LOG-3-Q_IND: capwap_ac_sm.c:5947 Invalid AP event (7) and state (4) combination
*spamReceiveTask: Jun 19 12:06:49.880: %CAPWAP-3-INVALID_STATE_EVENT: capwap_ac_sm.c:5947 Invalid AP event (7) and state (4) combination

We are intending to put rules in place to prioritise CAPWAP traffic across the MPLS to Singapore as Cisco recommend.

Does anyone have experience of a similar issue and whether prioritising the CAPWAP traffic will solve the issue I am seeing. I am a bit doubtful because my understanding is that prioritising the CAPWAP traffic will only make any difference if there is congestion on the MPLS link.

Thank you.

rgrds,

inayat

maldehne · ‎06-19-2012

It is very good practice to prioritize CAPWAP traffic while travelling from the AP to the central controller site.

One more thing , make sure about the other requirements for HREAP which are mentionend int the following link:

http://www.cisco.com/en/US/partner/products/ps10315/products_tech_note09186a0080736123.shtml#WAN

You can run the following debugs to figure out what is happenning :

on AP:

debug capwap client event

debug capwap client error

on controller

debug capwap event enable

debug capwap error enable

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Inayat Bunglawala · ‎06-19-2012

Thanks, maldehne. Do you have example configuration that should be applied to mark the CAPWAP traffic at the exit router? I looked at the Cisco website for examples and could only find the document below and the example it lists seems quite old (it refers to LWAPP). Thanks for any help in advance.

rgrds,

inayat

http://www.cisco.com/en/US/docs/solutions/Enterprise/Mobility/emob41dg/ch5_QoS.html#wp1022491

Example Router Configurations

This section contains router configuration examples to be used as guides when addressing CS6 remarking or LWAPP control traffic load.

This example uses LWAPP APs on the 192.168.101.0/24 subnet, and two WLCs with ap-managers at 192.168.60.11, and 192.168.62.11.

Remarking Client Generated CS6 Packets

The following shows a sample configuration for remarking LWAPP data packets marked as CS6 to a more appropriate value of CS3. This moves the traffic to a more suitable classification, at the level of call control, rather than at the level of network control.

class-map match-all LWAPPDATACS6

 match access-group 110

 match  dscp cs6

policy-map LWAPPDATACS6

 class LWAPPDATACS6

  set dscp cs3

interface FastEthernet0

 ip address 192.168.203.1 255.255.255.252

service-policy input LWAPPDATACS6

access-list 110 remark LWAPP Data

access-list 110 permit udp 192.168.101.0 0.0.0.255 host 192.168.60.11 eq 12222

access-list 110 permit udp 192.168.101.0 0.0.0.255 host 192.168.62.11 eq 12222

access-list 111 remark LWAPP Control

access-list 111 permit udp 192.168.101.0 0.0.0.255 host 192.168.60.11 eq 12223

access-list 111 permit udp 192.168.101.0 0.0.0.255 host 192.168.62.11 eq 12223

maldehne · ‎06-19-2012

You can use similar syntax to remark the CAPWAP traffic , all you need to do is change the port numbers to 5246 for CAPWAP control and 5247 for CAPWAP DATA.

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