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Cisco Aironet 1231 AP load balancing issues

Last Modified: 2013-11-12
I have a small office with about 40 wireless laptop users.  We have three Cisco Aironet 1231 Access Points setup for signal distribution and load balancing.

To help properly distribute coverage we have placed two AP's on the 2nd floor and one AP on the 1st floor.  They are all geographically separated from each other.  All have the same IOS and a uniform SSID.  Each is configured to use a specific channel that we selected based off the results of our site survey.  Each is configured as a stand alone access point (no repeaters or bridging)

The problem is, most users will connect to an AP and stay connected to it no matter what.  As they travel through the office (1st floor, 2nd floor, conference rooms etc) they maintain a persistant connection to their original AP (which is by design, I understand)  I need to figure out a way for them to be handed off to an AP that is closer by and will most likely have a lighter load.

I know that the 802.11 specification does not include anything about load balancing.  I understand that when a new client comes up and attempts to connect to the wireless network it will select the AP with the strongest signal (regardless of the user load on that AP)

My strategy up to this point has been to adjust configuration options such as: Max Clients, Transmit Power, Client Power, Beacon Period, Max Data Retries and Client Timeout.  I have not found a comfortable configuration for my users that will allow them to stay connected (other than running an occasional repair on their adapter)  We have a number of applications that require persistent connections.  Running a repair breaks these connections and is causing productivity issues.

To add complexity, we are in a heavily populated office environment.  There are dozens of nearby Access Points and other devices that cause RF interference.  We run a site survey at least once a month to discover additional access points being brought on by other folks in the nearby area and usually end up adjuting ours (channels etc) to compensate.

Has anyone had any success in deploying multiple AP's in close proximity in an attempt to properly load balance a few dozen clients?

Oh - and having the Aironets select the least congested frequency isn't something we're interested in going back to.  That was a complete nightmare a few months ago ;)

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Thanks for the replies guys.  I will split points so:
btassure: Thanks for your reply.  I actually had to drop the transmit power down to its lowest setting for the two 2nd floor APs.  1st to 2nd floor traversal is still a slight problem, but only with one or two users.

pulkit1982:  I had already disabled the 802.11b settings, but failed to mention it in the original post.  We had also disabled Aironet Extensions on all three APs.  I just did a bit of reading here: http://www.cisco.com/en/US/docs/wireless/access_point/12.3_8_JA/configuration/guide/s38rf.html#wp1135928 about what the Aironet Extensions do and I think you've pointed me in the right direction.  We're currently testing the adjustments that limit client power.  I am unable to find any additional commands for load balancing so I'm assuming this is automatically handled through discovery.  Since we've turned down the transmit power of the APs they no longer show up on the Adjacent AP list and I'm a bit concerned about cranking them all the way back up (especially since I think we originally had Aironet Extensions turned on)

Anyways - sorry I left this question open for so long.  I figured it would be best to close it now and split points.  I'll continue to work on the problem as we have time with your suggestions.

- Matt

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