CAPWAP timers

[janesh_abey]

Hi all,

We are looking at options in the design stage  to increase the AP timers so that HREAP APs will not go standalone  due to bad WAN links.

One possible way to achieve this is to disable heartbeat  which is is the default setting.

The other  option that I could see to acheive this is by tuning CAPWAP timers.

Not too sure whether tuning CAPWAP timers is the best approach.

Having said that, Table 8-17 of Cisco WLC config guide pg 505 implies that  we could adjust CAPWAP timers.

However I cannot see this option under the  AP advanced tab on  the WLC. WLC is running 7.0.98.

Any advice is much appreciated.

cheers,

janesh

[Scott Fella]

You can adjust some timers, but from the CLI:

http://www.cisco.com/en/US/products/ps6366/products_tech_note09186a00809a3f5d.shtml#backinfo

[janesh_abey]

Hi Scott,

Thanks  for taking time to reply.The link only provides details on fast-ap-configuration timers.

My query was in relation to CAPWAP timers.

On the same topic, HREAP deployment guide states that "Roundtrip latency must not exceed 300 milliseconds (ms) for data and 100 ms for voice and data between the access point and the controller"

The doco (hreap deployment guide, Cisco WLC 7.0 config guide and networkers slides) does not indicate what are the consequences if we exceed the recommended RTT values.Put it differently whats the exact impact on data and voice?

Also what is the consequence of disabling hearbeat for H-REAP WAP? If the WAN link fails I beleive the CAPWAP timers come into play to enforce standalone mode of operation.

Thanks,

Janesh

[Scott Fella · Accepted solution]

Well basically if your latency is greater than the requirement, there is no guarantee it will work. You can't guarantee voice calls at all and for data, you also risk AP's going to stand alone mode. You might want to deploy those AP's in autonomous mode if you have issues with the AP join. This will not help though if you are running voice. Like the guide mentions, you would have to priorities the capwap traffic.

Here is a doc on lwapp traffic study

http://www.cisco.com/en/US/tech/tk722/tk809/technologies_white_paper09186a0080901caa.shtml

Sent from my iPhone

[janesh_abey]

Hi Scott,

Many thanks  for the reply.That is exactly waht I was after.

cheers,

Janesh